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04 University of Plymouth Research Theses 01 Research Theses Main Collection
1973 FORMATION AND REACTIVITY OF SOME METAL BORIDES AND CARBIDES
CHAUDRY, ASGHAR ALI http://hdl.handle.net/10026.1/1855
University of Plymouth
All content in PEARL is protected by copyright law. Author manuscripts are made available in accordance with publisher policies. Please cite only the published version using the details provided on the item record or document. In the absence of an open licence (e.g. Creative Commons), permissions for further reuse of content should be sought from the publisher or author. FORl-lATION AND REACTIVITY OF SOI^ METAL BORiDES AND CARBIDES
A Thesis presented for the Research Degree of
DOCTOR OF PHILOSOPHY
of the
COUNCIL FOR NATIOMAL ACADEMIC AV/ARDS
LONDON
by
ASGHAR ALI CHAUDHRY
John Graymore Cheinistry Laboratories, Department of 14athematical and Physical Sciences, Plymouth Polytechnic, PLH^OUTH, Vlh 8AA, Devon. November 1973 55u0248 ABSTRACT
Most recent developments in the production, properties and applications of borides and carbides are revie'v-red.
The reactivity and sintering of finely-divided boron carbide with metal additives has been investigated. The additives (Fe, Ti,
Zr, V, Nb, Ta, Mo, W and Al) generally promote sintering of the boron
carbide. Their effectiveness is reduced occasionally when there is
some surface activation caused by the metals reacting vjith the boron
carbide to form metal borides and carbides of different, crystal
lattice type and molecular volume. The more metallic character of
the bonding in the metal borides and carbides enhances surface and
crystal lattioidiffusion at the grain boundaries of the more covalent
boron carbide. Iron is much more effective than the other metal
additives tested in promoting sintering of the boron carbide at 1300°C
since it forms the lowest-melting borides. It also enhances sintering
during hot pressing of boron carbide at this temperature, but even —2 7 -2 with pressures up to one ton in (1.5U x IO'NIIK ) the densification
does not exceedof theoretical. Further research on hot pressing
of more ionic borides such as CaB^ indicates that for most borides
and carbides, including boron carbide, final consolidation of the
material is not achieved imtil a temperatxire of about 90% of the
melting point (in K) is reached.
Various metal foils e.g. Fe, Ti, Zr, V, Nb, Ta, Cr, Mo and V/
were coated with a dispersion of boron carbide and heated under argon
at fixed temperatures for S hours. This produced mixed phases of
borides and carbides which varied in their composition and pene-
11 tration according to the metal substrate. Microhardness measxirements showed that the coatings were harder than the surfaces of the original metals.
Factors influencing the oxidation of the metals, metal borides and carbides and unreacted boron carbide in the above metal coatings have been investigated. The oxidations are often controlled by- solid-state diffusion processes, giving parabolic kinetics ^ich become linear if the material sinters extensively. The Tammann
temperatures of the reactants and products are significant in the
sintering and agglomeration of the oxidised material.
iii ACKNQWLEDGEt-ENTS
The author wishes to express his sincere thanks to
t
Dr. D,R. Glasson and Dr. J.A. Jones for their helpful advice,
guidance and constant supervision throughout the course of this work. He is grateful also to Dr. S.A.A. Jayax-reera for his advice,
co-roperation and valuable discussions.
He is gratefultoMr. K.J, Matterson, Borax Consolidated Ltd.,
Chessington, for industrial supervision and Dr. R.H. Biddulph and
Dr. C. Brown for their constructive and valuable suggestions; also
to Mr. L. Bullock, Diamond Products Research Laboratories, Torpoint,
Cornwall, and to Mr. Matterson, for hot pressing facilities; to
Mr. D. Short for assistance with the metallographic examinations and
to Mr. D. Sargent and Dr. B.J. Brockington for assistance in the use
of the scanning electron microscope at the Royal Naval Engineering
College, Manadon, Plymouth.
He would like to thank the Governors of the Polytechnic for
granting him a research assistantship.
He is grateful to Dr. A.B. Meggy and Dr. CM. Gillett for
allowing the use of research facilities. His thanks are also due to
the Polytechnic Library staff for their assistance and the Computer
staff for programming facilities.
He is thankful to Mrs. A. Harman for her special care in typing
the manuscript.
IV CONTENTS
Chapter Section Page
1 GENERAL INTRODUCTION 1 - li
Aims of the present work 3
The structure of the work h
PART I DISSERTATION 5-90
2 ' REVIEVJ OF BORIDES * 6-63
2.1 Introduction 6
2.2 Production techniques 6
2.3 Thermodynamics of borides and carbides 11 formation
2.3.1 Ellingham diagrams ; 11
2.3.2 Application to production processes 1h
2.U The structure of boron carbide in 21 relation to its reaction with metals
2.5 Bonding and crystal structure of .. 23 borides and carbides
2.6 Properties of borides and carbides 25
2.7 Sintering of borides and carbides 25
2.7.1 General principles of the mechanism 30 of sintering and hot pressing .
2.7.2 Role of voluire, grain boundary and 32 surface diffusion
2.7.3 Role of dislocations 136
2.7.ii Role of atmospheric effects .... 37
2.7.5 Computer-simulated models of sintering iiO
2.7.6 Reaction pressing and pressiire ill sintering
2.7.7 Effect of wetting on sintering 1x3
2.7.7.1 General principles i;3
V Chapter Section Page
2.7.7.2 Wetting problems in the sintering of U6 borides and carbides vrlth metals
2.8 Industrial applications of borides 5l and carbides
2.9 The present research 62
3 EXPERIMENTAL TECHNIQUES 611-90
3.1 X-ray diffraction 6h
3.1.1 X-ray generators 6U
3.1.2 The counter diffractonmeter 61;
3-1.3 X-ray line- (or peak )broadening ... 65
3.2 Theory of electron microscopy .- 67
3.2,1 Apparatus 69
3.2,2 Preparation of samples 70
3-2.3 . The replica techniques and shadow ,. 71 casting "
3.3 Scanning electron microscopy .. ,. 72
3.U Thermoanalytical techniques .- .. 75
3-5 Surface area measurement by gas ... 76 sorption
3.5.1 The apparatus 78
3.5.2 Measurement of sorption isotherms .. 79
3.6 Sintering of materials 80
3.6.1 Construction of high temperature .. 81 furnace
3.7 Reaction sintering of boron carbide . Qh with metals by hot pressing
vx :hapter Section Page
3.7.1 Laboratory hot pressing system .. 8^
3.7.2 Industrial hot pressing systems .. 86
3.8 Hardness testing of coatings .. ., 88
3.8.1 Mounting of samples 88
3.8.2 Polishing 88
3.8.3 Projection microscope and microhardness 89 testing equipment
3.8.3.1 Microhardness Tester ...... 89
3-9 Computer programming 90
PART n THESIS 91 - I8O
U REACTIVITY AND SINTERING OF BORON
CARBIDE mUti I4ETAL POVJDER ADDITIVES 92 - iWi
11.1 Introduction " .. 92
11.2 Experimental 92
U.2.1 Materials 92
U.2,2 Procedure '.. 93
li.2,3 Results 93
U.3 Discussion 9U
U.3.1 Iron additive 91;
ii.3.2 Titanium and zirconium additives . ., 99
U.3-3 Vanadium, niobium and tantalxim ,. .. lOU additives
U.3.U Molybdenum and tungsten additives .. 109
li,3.5 Aluminium additive II6
U.U. Electron microscopy data ' ,ll8
• U-U.l Iron additive II8
U.U.2 Titanium and zirconim additives . 121
vii Chapter Section Page
k*h'3 Vanadium additive 121
h'h'h Niobium and tantalum additives ' 128
U-U-5 Molybdenum and tungsten additives .. 128
ii'.ii.6 Aluminium additive 126
Conclusions r- ••. Iii2
5 EFFECT OF ADDITIVES ON THE HOT PRESSING '
OF BORON CARBIDE ~
5.1 Introduction . Iit5
5.2 Experimental Iii5
5.2.1 Materials IIAS
5.2.2 Procedure - Ik6
5-3 Results 1U6
5. U Discussion Ili8
6 THE FORMATION AND MICROSTRUCTURE OF BORIDE AND CARBIDE COATINGS ON METAL lb? - l6U SURFACES
6.1 Introduction Ii49
6.2 Experimental 11^9
6.2.1 Materials m9
6.2.2 Procedures l5l
6.3 Res\ilts • 151
6. U DiscTission l5l
6.11.1 Iron 162"
6.21.2 Titaniiam and zirconium 162
6.U.3 Vanadium, niobium and tantalum .. 163
6M*h Chromium, molybdenum and tungsten l6ii
6.5 Conclusions : I6i4
vili Chapter Section Pa^e OXIDATION OF BORON CARBIDE. METALS 7 AND METAL BORIDES AND CARBIDES - 176
7.1 Introduction 165
7:2 Experimental I66
7.2.1 Materials 166
7.2.2 Procedxire 166
7.2.3 Results * 167
7.3 Discussion I67
7.3.1 Oxidation of boron carbide ...... 167
7.3.2 Oxidation of boron sub-oxide 173
7.3.3 Oxidation of titanium, titanium hydride 173 and titanium + boron carbide
CONCLUDING SUMMARY I77 . 180
8.1 Pressureless sintering of boron carbide 177 with additives :.
8.2 Hot pressing of boron carbide with , . 177 additives
8.3 Microstructure of borides and"carbides 178 formed on metal surfaces
8.1; Oxidation of boron carbide and some 179 metal borides and carbides
8.5 Future developments • ^ ^ ^ ^ 180
REFERENCES xi - xxiv
APPENDICES Appendix-I; xxv - xxxv Particle size measurement by X-ray xxvi method, computer programme and table values of particle size
Appendix H; Computer programme for calculation of xxx thermodynamics functions and tables of thermodynamic data for borides and carbides •
ix Appendix III; Computer programme for graph plotting xxxii
Appendix IV: Computer programme for calculation of xxxiii fractional volxime change for conversion of metals to borides and carbides and their subsequent conversion to oxides.- Fractional volume change tables for borides and carbides CHAPTER 1
GENERAL INTRODUCTION
During the last fifteen years an increasing industrial demand for refractory hard materials, especially in the fields of Aviation,
Space and Nuclear Industries, has intensified the research on borides and carbides. Among the most desirable properties of these materials are their high melting point and thermal stability, hardness, as well
as specific electrical and magnetic properties. In addition to their
very high melting point, modern refractories are recognised by a
combination of other important properties such as hot hardness
(hardness at high temperatures), resistivity to highly reactive agents,
low vapour pressure and evaporation rates. Dependence of these
properties of refractory borides and carbides on their electronic
structure is explained (Qiaffer & Samsonov, 196iia).
The refractory borides and carbides that have attracted
extensive research studies are those of transition metals, lanthanides,
actinides, and aluminium (Schwarzkopf & Kieffer, 1953, Samsonov, 196Ua)..
The electrons of the incomplete d- and f- levels of the transition
metals take part in the formation of chemical bonds in the crystal
lattices of these compounds (Samsonov, 1967). The refractory metal
borides and carbides possess most of the properties of metals and
alloys and they exhibit heterodesmic chemical bonding, properties of
each type being characterised by their crystal structure. Binder
metals such as chromium, cobalt and nickel are used in the formation
of 'hard metals', i.e. cemented carbides and borides (Schwarzkopf fic
Kieffer, 1960). Some of the borides and carbides exhibit metalloid properties, e.g. they are semiconductors and have high electrical resistance. These are compounds of boron and carbon with each other and with other non-metals such as N, S, P and Si. These compounds are characterised also by the heterodesmic chemical bonding in their
ciystal lattices, but vrLth covalent bonding predominating. This
contributes semiconductor properties and high electrical resistance
at room temperature. They exhibit layer, chain or skeletal structure
patterns and they decompose either at their melting points or slightly
higher temperature.
Nevertheless^some borides and carbides are intermediate between
the above-mentioned metallic and non-metallic groups as regards their
refractory properties. Aims of the present work
Although other workers have prepared borides and carbides for
use as refractories, their investigations have been mainly empirical
and viewed from a commercial angle. Their aim has been to form
products vjith improved properties, e.g. with higher microhardness
values. Systematic investigations correlating crystallographic
properties with time and temperature of formation have not been
carried out before.
One of the aims of the i)resent work has been to produce metal
borides/carbides starting from boron carbide + matal, attempting to
improve the properties of the finished product. Thus, the production
of boride/carbide surfaces of metal foils with superior microhardness
values was one of the objectives. Also the densification of boron
carbide by pressureless sintering and hot-pressing with powdered
metal additives vjas attempted. Densification \isually leads to the
improvement of mechanical properties.
In the reaction of borohcarbide with metals, change: in
crystallographic properties v/ith temperature, reaction time and nature
and arnoxmt of metal additive was investigated, attempting to optimise
the reaction condtions. Previous workers have worked mostly with a
single metal in each case- In the present V7ork,the sintering behaviour
of the products has been studied systematically over a wide range of
metals.
The stability of the products was assessed by comparing their
behaviour on oxidation vjith that of the original materials, viz.
boron carbide and. the metals. The oxidation of boron carbide of
submicron size has been studied previously in these. laboratories,
In the present work^the investigation has been extended to the material above this range. Oxidation studies were also carried out on titanium metal and some related products.
The struct lire of the work
The work is presented in two parts - dissertation (Part l) and thesis (Part II).
Part I gives the general backgroiind to the work. This includes a review of studies carried out by previous vforkers on the formation and reactivity of borides and the theoretical background related to certain aspects of the v;ork. In Chapter 3 the experimental techniques are summarised and a brief description of the underlying theoretical principles is given.
In Part II, the results of the present vrork are described and discussed in relation to the theoretical principles and the results of previous workers. PART I
DISSERTATION
Chapter 2 Review of borides and carbides
Chapter 3 Experimental techniques CHAPTER 2
REViro OF BORIDES
2.1 Introduction The formation and reactivity of borides was the subject of
several reviews, e.g. Aronsson (1960), Thompson & Wood (1963),
Thompson (1965, 1970a, 1970b, 1970c, 1971), Nowotny (1972). A
comprehensive account of the subject was also given by Glasson and
Jones (1969a), In this chapter the review has been updated.
Ifethods of production of borides are tabulated in the following
section- The references include phase-diagram studies on metal-boron
systems as well as patents on methods of producing borides, vrLth
ijnproved properties. Thermodynamic data for the formation of borides are presented
in Section 2.3, and compared with that of other refractories. This
is followed by discussion of the relationship between bonding and
crystal structure of borides (Section 2.U)- Studies on the properties
of borides and carbides are tabulated in Section 2.5.
A comprehensive reviev; of the theories of sintering is given
in Section 2-6- This brings up-to-date an earlier review (Jones, 1970).
The industrial applications of borides and carbides are classified and
tabulated (Section 2.7).
• 2,2 Production techniques
Methods of production of borides and carbides were discussed
by Schwarzkopf & Kieffer (1953), Sauisonov (1956, 1959), Aronsson (1960),
Thompson & Vfood (1963), Thompson (1965, 1970a, 1970b, 1970c), Glasson &
Jones (1969a), Nowotny (1972a), Storms (1967, 1972), Toth (1971) and
Kosolapova (1971). Table 2.1 summarises studies carried out in recent
years on various aspects of the production of borides. Table 2.1 Borides
Boride Nature of publication Reference
Lithium boride Magnesium boride + lithium Maron & Germaide 1970 fluoride
BaB^ Mechanism of formation Torker et al 1971 Ba, Ca, Sr (MB^) Me + B Blizhakov & Peshev 1970
Aluminium and magnesium Mixed ores Vekshina et al 1971 boride s Aluminothermic process Samsonov & Neronov 1970
TB2 Y + B Markovski et al 1969 Y + B 0> Dinstov St Paderno ^12 1971
TiBg Single crystals in Al Higashi fit Atoda 1970 TiB2 BCl^ + TiCl2^+5H2 Takahashi et al 1971
ZrBg Zr + B Voroshilov & Kuz'ma 1969
Cr^B, Cr^, CrB, Cr^B^, Cr + B Serebryakova & Samsonov 1967 CrBg NbB, Nb^B, NbB, Ta^B^, Nb20^ - NbB2 Marek et al 1971 TaB, Ta2B, Cr^B, CrB Ta2C^ - TaB2 Cr20^ - CrB2
Molybdenum boride . Coatings Karev et al 1967
Zirconium, Chromium, Carbothermic process Meerson fitGorbuno v molybdenum borides 1969
Tungsten boride Phase diagram up to 2370?C Kuz'ma et al 1967
CaB^, S^B^' BaB^, CeB^, Borothermic reduction Blizhakov fit Peshev 1970 PrBg, NdB^, TiB2, ZrB2, ' HfB2, VB2, NdB2, TaB2,
CrB2, M02Bg, V72B^ •
AIB2; TiB2 VapoTir deposition Blizhakov fit Peshev 1970 Table 2.1 (cont'd)
Boride Nature of publication Reference
Niobium, tantalum, Me + B Samsonov et al 1970b molybdeniim and tungsten borides
TiB2, ZrB^y U£B^y VB^, Borides + C 2O0O-3000°C Levinskii et al 1968 NbBg, TaB2, CrB2, MoB, M02B5
TiB2, ^2^S* chromium Me + B Oreshkin 1971 boride Borides of metal group In powder form from Gurin et al 1971 IVA - VIA solution in molten zinc
Mn^B, Mn2B, MnB, Mn^B^, Mn + B, phase diagram Markovskii & Bezriik 1967 MnB2, MnB^ Re^B, Re^B^, Re2B Re + B Portnoi & Romashov 1968
FegB, FeB Fe + B Deger et al 1972 FOgB, FeB Fe + B^C + 1^ NH^Cl Minkevich et al 1967 also Fe + B^^C + Na2Bj^0^
FeB Boronizing by B^C - . Muta et al 1968 alkali' metal carbonate
FeB Boronizing by boron Protasevich et al 1972 Fe2B, FeB Composition of hot bath Hosokawa & Kogakubu „^ for boronizing iron 197^: C02B, Co^B Cobalt boride s ^ Markovskii et al 1971 Nickel borides Nickel borides + C ) Vanadium, iron, cobalt BCl. + + Mea. ) Cueilleron et al 1971 Nickel Borides, CrB^ „ „ „ 700-1000°C \ TiB2, VB2, CrB2 B + MeS^^^ — ^ ) I^Bg La20^ Meerson et al 1970 LaB^ Production of complex Medvedev et al 1971 shape s Ta2B2, TaB, Ta^B^, LaB, + Ta ) Gert et al 1969 ^ ) TaB2, M02B, -Mog LaB^ + Mo ^ Table 2.1 (cont'd)
Boride Nature of pi±>lication Reference
LaB^, CeB^, PrB^, LuB^ Metal flux + B Fisk et al 1972 Me + B or MeO + B^O^ + C Etourneau et al 1970 SrBg, LaB^, ^^6' "^^6 X 2 3 SmB^ 2Sm20^ + (6+lx) B Niihara 1971
'SmB^, NiB, Ni2B, Ni^B^ SmB^ + Ni, phase diagram Romashov et al 1970 Borides: general review B.C. plasma De Vynck 1970, 1971 of methods
Boron carbide briquette Hot pressing Maire et al 1969 patent Boron and boron carbide Vapoiir deposition Cochran & Stephenson coatings on objects 1970
Boronizing of forging Article + B Vincze 1969 dies
Mixed borides
Borides Natiire of publication Reference
Aluminitim, magnesium Metals + B Vekshina et al 1971 boride
MoBC Mo + B + C Salibekov et al 1970 SrBg LaB^ Borothermic process Blizhakov & Peshev 1970 BaB^ LaB^ W-Cr-B, VJ-Mo-B Phase diagrams Telegus & Kuz'ma 1968
(Ti, Cr) borides Alloy + B Oreshkin et al 1971
Fe-Fe^B-Fe^C Equilibriiam phase diagram Fomichev et al 1971
Co^B^C Co+B+C or Co^B+Co^C+Co Markovskii et al 1971
B^QB^C Pyrolysis of BBr^-CH^- Ploog et al 1972 H2 on tantalum substrate
-do- - N2-H2 on BN Ploog et al 1972 substrate
C - B2^C -.X B^C + C + oxide Srbobran 1969 X = fluorides, V^O^
MgO, Al20^, SiO^ Table 2.1 (cont'd) Carbides
Carbides Nature of publication Reference
Titanium, zirconium Me -i- C Davydov et al 1970 carbides
IVA - VIA group metals In powder form from Gurin et al 1971 carbides solution in molten zinc
General review of B.C. plasma De Vynck 1970, 1971 methods of production
Preparation of boron By using a radio-frequency MacKinnon & Wickens carbide plasma 1973
10 2.3 Thermodynamics of boride and carbide formation 2.3.1 Ellingham diagrams
The variation of standard free energy of formation A and the production and stability of the various borides and carbides were correlated over wide ranges of temperature (Shaffer & Samsonov, 196ii, JAN/lF tables 60-72). The temperature variation of-^G°^ per g-atom of boron and carbon is compared for the formation of borides and carbides, figs. 2,1-2.3. The temperature variation of standard free
energy is best represented by Ellingham diagrams {19hh). Fig. 2.1 represents the free energy of formation of the boride, carbide and oxide of titanium. Plots for other metals give similar results. Fig- 2.2 compares the standard free energies of formation of different methods of formation of boron carbide. Fig. 2.3 compares the thermo- dynandc data for various methods of formation of titanium diboride.
Equilibrivun compositions of the systems represented on
Ellingham diagrams are readily readable over the desired temperature
range by the Richardson fit Grants (199i) nomographic scale. High temperature materials such as borides, carbides and other refractory materials have signif icantli^arge vapour pressures at moderate temper- • ature, limiting their practical applications at higher temperatures.
The Ellingham diagrams for these compounds are usually linear. Their
slope depends upon whether thermodynamically the reaction proceeds in
the forward or reverse direction as the temperature is increased and o/v.
volume changes accompan[ying the reaction- Other factors as the
temperature-sensitivity of the extensive properties are approximately
interbalanced:
AG°^ = AH° - TAS°
A plot of the free energies of formation of boride, carbide
11 and oxide, fig. 2.1, of titanitmi compares its relative affinities for boron, carbon and oxygen and gives important information about the co-existence of these compounds. The points of intersection of the cTirves show the equilibrium co-existence of each pair of compounds.
At all other temperatures, the compound with the more negative free energy will be the more stable. This will determine the direction of the interconversion of the compounds at different temperatures.
Analysis of free energy data (Schwarzkopf & Glaser, 1953) shows that diborides of the fourth and fifth odd (A) metal subgroup have higher thermodynamic stability than of other metals. Diborides of other groups, e.g. MgB2 and CrB2, show a decreasing trend in stability as compared with group IV. Diborides of group IV transition metals and monoborides of group VI transition metals (Schwarzkopf & Glaser,
1953) are the most stable of all the borides. In group V different borides of the same transition metals have similar thermodynamic stability. For group IV, V and VI, the M-B bond strength, as deduced from a comparison of m.p. of borides, increases with the atomic weight of the metals in each period and decreases with atomic weight within each group.
Despite their usefulness, Ellingham diagrams have some inadequacies, viz.
(i) The distribution of the reactants and products between
the different phases is not taken into account.
(ii) The formation of intermetallic compoxmds and other mixed
phases between products and reactants is possible.
(iii) The compounds are assumed to be of definite composition,
although in practice this may not be so for many
refractories.
. - 12 Fig. 2.1 Ellingham diagram for TiC, TiB^, Ti02
-56,0
-97.0
u -138.0
179.0
-220.0 4000 0 800 1600 2400 3200
Temperature K
13
(After Schick, 1966) (iv) They indicate only whether a process is thermodyanically
feasible, but not whether it is kinetically favourable.
In particular, solid-state reactions which are thermo-
dynamically feasible are often kinetically unfavourable;
this might apply to reactions involving borides and
carbides.
(v) The free energy changes refer to standard states only,
conditions never realised in dynamic systems.
However, these inadequacies do not diminish the value of the diagrams in terms of their ready evaluation and ease of interpretation. Sources for reliable thermodynamic information are the. U-S. Bureau of Standards
(Publication 1952, etc), JAMF Thermochemical tables and Supplement
(1960-71), Schick (1966) and Wicks & Block (1965)- The second most important thermodynamic fxinction is the enthalpy change of the reaction. It shows the endothermicity or exothermicity of the process.
It is applicable to open and closed .processes, i.e. those involving
formation of gaseous products from solids and condensation of initial
gaseous reactants to form solids.
2.3.2 Application to production processes
Free energy changes have been plotted against temperature for
six methods of production of- boron carbide as shoim in fig. 2.2. A
brief discussion of this information for each reaction is given below:
(i) 2B2O3+ 7C = B^C+6C0(g)
Thermodynamically feasible at temperatures y 2320K. The
operating free energy
AG^ = AG*^^+RTlnp(CO)
shows that an 'open' system would be favo\irable. However,
if the volatile natiire of B20^ is taken into consideration,
the equation becomes:
• lit Fig. 2.2 Ellingham Diagrams for Boron Carbide.Formation
460
316
as o M Q)" 'O 172 •H J3 U to o c o o ja u 26 0) a *. Eh o
116
260
600 1200 1800 2400 3000 Temperature K Numbers refer to reactions in table 2.2
(After Wicks & Block, 1965)
15 TABLE 2.2
BORON CARBIDE
Feasibility Heat of Reaction Range Reaction Eq. Constant K kcal mol O...I1OOOK O-.-lOCOK
1. 2B2O2+7C = B^O • 6Co >2300 U48.a.-22 . 0...1X10^ OS 2. 2B202+6Mg+C = B^C+6MgO O...2li00 -252...-7li5 10^^...0
3. liBCl^+lH^+CH^ = B^C+12HC1 >1700 123...80 0.,.1X10^
ii. UBC1^+8H2+CC1J^ = B|^C+16HC1 >300 5ii...-56 O.a.lO-^-^
5. IIBC1^+6H2+C = B|^C+12HC1 >3300 106...50 0.. .3
6. liB+C = Bj^C O...3IOO -lOa..-75 10^^..0 Fig. 2.3 Ellingham Diagrams for Titanium Diboride
170
o B U a
-H u o (0 o O f-i -H M
800 1600 2 400 3200
Temperature K
Numbers refer to reactions in table 2-3
(After Schick, 1966) 17^-_ TABLE 2.3 TITANIUM DIBORIDE
Heat of Feasibility Eqm. Constant Reaction Range Reaction
k cal mol 0 O...UOOOK ...iAOOQK
1. Ti + 2B = TiB2 0... -66...-U03 10^*^... 10^
2 Ti02 + 2B + 20 = TiBg + 2C0 >1300 10I1...62 oo TiCl^ + 2BC1^ + SHg TiB2 + lOHCl > 1200 99...ai 0...3X10^
TiOg + 620^ + 5C = TiB2 + 5C0 >1$00 327...120 0...10^^
2Ti02 + B^^C + 30 = 2TiB2 + iiCO >1200 217...383 o...io^-^ io39...ioi7 3Ti + B^C 2TiB2 + TiC 0 -155... Ill io^^..ioi6 2Ti + B^C 2TiB2 + C 0-...- -120,..52
8. 3Ti02 + 3B20^ + lOAl - 3TiB2 + SAlgO^ 0...3200 -56...-659 10^^...0
9. Ti02 + BgO^ + 5Mg = TiBg + 5MgO 0... -2li3....232 10^^...lo' AG^ = AG^^-RTlnp(B20^)+RTlnp(C0)
Hence, an 'open' system may not be favourable, particularly
• at higher temperatures,
(ii) 2B20^+6Mg+C = B^C+6MgO
The reaction is thermodynamically feasible over the
temperatxire range 0-2500°C (Glasson & Jones, 1969). The
optimxim operating temperature must be determined by the
kinetics involved. The reaction is exothermic (i.e. ^ H^
is negative) and the operating free energy change is given by:
AG^ = /:^G°^-RTlnp(E20^)-RTlnp(Mg)
This suggests that a 'closed' system is preferable; this
is likely to favour the kinetics of the process.
(iii) i4BCl^+iiH2+CH|^ = B^C+12HC1
This reaction is thermodynamically feasible above 1700K.
The optimum operating- temperature must be determined
from the kinetics involved.
(iv) hBCl^+8H2+CGl|^ = B^C+16HC1
The reaction is thermodynamically feasible at all ten^er-
atures greater than 300K-
(v) iiBCl^+6H2+C = B^C+12HC1
The reaction is thermodynamically feasible at temper•
atures greater than 3100K.
(vi) liB+C = B^C
The reaction of elemental^.- rhombohedral boron with
graphite is thermo(^niamically feasible over the
temperature range 0-3100K.
19 ThermodynajTri-C functions for the metal borides of group IVA-VA have been computed over the temperature range O-iiOOOK. Free energy
change values have been plotted to compare the various methods of
formation for TiB2. A table of free energy change, heat of reaction
and equilibrium constants at different temperatures for one of these
reactions is given in Appendix II. Complete tables are available for
all methods of boride production for the metals titanium, zirconium,
hafnixim, niobium, tantaliim and magnesium.
Fourth and fifth odd (A) subgroups metal carbides are of the
highest stability, e.g. SiC and TiC. This systematically drops for
carbides of lower groups, e.g. CUC2 and AlC^, and transition metal
carbides in groups VI to VIII, e.g. WC.
A comparison of the relative reactivity of metals towards boron
and carbon shoves that borides are comparatively more stable than
carbides and easily formed. This behaviour is attributed to the
comparatively open structure of elemental boron compared with that
of carbon. Boron retains its elemental groupings, while carbon lattices
are disrupted during reaction. This makes ready ingress of the metal
component possible to form the binary boride, e.g. AIB-^^Q (but not A1B^2)
(Will, 1966); also ScB-j^2 ™12 "^^^^ B-j^-cubo-octahedra
(Matkovich et al, 1965)' The solubility of boron in transition metals
is relatively low except when it substitutes an atomic site in the
metal, thus causing shrinkage of the unit cell (Hansen fit Anderko, 1958;
Pearson, 1958; Aronsson, 1960) (e.g. with Mo- and W-B alloys). Any
increase in the cell dimensions of the transition metals is an
indication of the interstitial dissolution of boron except when such
increases are due to the uptake of nitrogen or oxygen. These elements
though more electronegative are small enough to be dissolved inter-
20 stitially. Homogeneity ranges of primary solid solutions are consider•
ably affected by the free energy of intermediate phases. The inter•
stitial solubility of non-metals in solid metals is controlled by
electronic factors also. This is discussed in the next section .
2,h The structure of boron carbide in relation to its reaction vo-th metals The crystallo-chemical structure of boron carbide and its reaction with titanium and chromium has been comprehensively reviewed by Jones (1970). A brief discussion of the structure of boron carbide and its relation to its properties and reaction with iron and other metals is presented below-
The structixre of boron carbide with composition of B^2^3 ideally represented by regular icosahedra where 12 boron atoms are situated at the vertices and has interstitial spaces to accommodate
up to 3 carbon atoms. The two end carbons in the -C-C-C- chain differ from the central carbon which may be replaced by boron atom giving the
compound of composition B-j^^C2* A homogeneous continuous mixture of these two compositions is considered to constitute the boron carbide
compound. According to Fourier synthesis of electron densities of 2+ 2- boron carbide two formulations are suggested: (i) Cj B^^ 5 (ii)
(CBC)*(B^C)~. Ordinarily a well-annealed boron carbide of B^^C
composition is structurally formulated as (CBC)''^(B-QC)~ to indicate
probable charge transfer and is considered to be energetically
preferred. The rhombohedral latticeconstants.of boron carbide are
a-« 5.167^0.0035 and o<= 65-68;o.05 and a = 5-?82 and c = 12.0o2 for K O O its hexagonal cell containing three rhombohedral unit structures. Properties of boron carbide such as very high wear-resistance, abrasion-resistance, heat resistance and microhardness are explained 21 in terms of its electronic configuration (Oreshkin et_al, 1970).
Modern theory attributes its high abrasiveness to the fact that boron and carbon^in its composition attain the electronic.configuration 2 having highest stability. Boron atoms having s p configuration in 2 the ground state undergo s ^p transition to acquire sp configur• ation. This tends to stabilize further to sp^ configuration due to 2 2 attraction of the electrons of carbon atoms with s p configuration of valency electrons. Carbon xindergoes s->p transition to acquire more stable configuration. Thus in the lattice of the boron carbide the boron atoms will have the stability of sp"^ configuration by exchange of electrons between boron atoms and due to breakdown of the sp^ config• uration of carbon atoms. As a result of shortage of electrons for transition to sp^ configuration a part of the boron atoms remains with 2
less stable sp configuration. Thus compared with diamond and the analogous cubic boron nitride ('borazon») which have all the atoms with
sp^ configuration and hence highest stability (with respect to energy),
boron carbide has higher \-iaar resistance index. Because of this unique 2 3
electronic structure (partial conversion of sp to sp configuration of boron) all the remaining compounds are inferior to boron carbide in
resistance to wear and other properties. i
Improvement in the properties of boron carbide sintered with different metal powders (Chapter U) will depend upon the stability of
electronic configizration of the final product. In its reaction-with
iron, partial transfer of electrons takes place towards boron carbide, 2 3 which increases its stability by transition of sp to sp-' configuration.
At the same time the strength i2n2 the transition is increased due to an increase in the stability of iron due to transition of d^—> d^ config- uration. Thus iron has been found to be most effective sintering
additive in the present work (Table U.IO). The effectiveness of
other metals will vary according to the ease of electron transfer
and the stability of the metal atom as a result of this interchange
of electrons. Metals used in this work possess partially filled diorbit-
als in their penultimate shell and show variability of oxidation states.
It can be assumed that a dominating role will be played either by sp-
hybrid states of boron carbide, or the d-state of the metal in the
interaction of valence electrons. The precise nature of this phenom•
enon is still not too clearly understood. However, it would be logical
to sxiggest that transfer of electrons is directed towards boron carbide
if they acquire relatively stable configuration as a result of this
exchange.
2.5 Bonding and crystal structure of borides and carbides
A comprehensive reviex-j discussing the relationship between the
bonding and crystal structure of borides and carbides is given by
Glasson & Jones (1969a). A summary of this is given below..
It was pointed out (Hagg, 1931) that transition metal binary •
refractory borides and carbides have simple 'normal* structures if
the radius ratio r : r of the non-metal and metal atoms is less than X m
0.59 (corresponding to a metal to non-metal radius ratio of over 1.70).
Greater non-metal radii cause the unit cell dimensions of the inter•
stitial phases to extend and reduce the radius ratio for normal struct-
\ires. Despite the fact that decreased metal atom size leads to complex
structures, most of these compounds are metallic in nature. Later this
limiting radius ratio rule was found to be applicable only to carbides
(Schwarzkopf & Kieffer, 1953). This behaviour of borides has been attributed (Kiessling, 1950)
23 to the tendency of boron atoms to form chains, sheets or three- dimensional networks. Hagg's rule appears to be confined to phases
not containing directly interconnected non-metal structure elements.
Accordingly, eight different types of boride crystal structures have
been described by Schwarakhopf and Kieffer (1953) for boride phases
in the composition range M^B to MB-j^2' .More variations have been
reviewed later (Kieffer and Benesovsky, 1963; Post, 196Uj Aronsson,
Lundstrom and Rundqvist, 1965) with composition ranges M^^B to MB-j^2*
extending to MB^Q.
Most of the refractories (Hagg, 1931) discovered earlier were
monocarbides with radius ratios in the range O.Ul-0.59. These were
characterised by rock-salt structures irrespective of the parent metal
structure, Rundle (19U8) assumed the presence of octahedral metal to
non-metal bonding, and developed Pauling's original concept of
resonance of the bonds of U- covalent C amongst the 6 positions (Paxiling
19U0, 19U7, 19U9). Most of the properties such as hardness, high m.p.
and electrical conductivity have been explained in terms of resonating
bond structiires and ionic structures involving homopolar and hetero-
polar forces. A different theory, introduced by Ubbelohde (1931, 1937)
and Umanskiy (19U3) (see also Samsonov & Umanskiy, 195?) have been
developed by Samsonov and Neshpor (1958, 1959) and reviewed recently
for nitrides (Glasson and Jayaweera, 1968). According to this theory,
the non-metal contidbutes bonding valence electrons to the total
system of electrons, at least partially filling the electron defect of
the metal atoms. Interatomic bonding is f\irther strengthened by the
donor-acceptor interaction forces. Therefore, heats of formation of
borides and carbides '.increase with 'acceptor ability' "^Nn' of the
2h atoms of the metallic components, where N is the principal quantiim
number of the partially filled d- (or f-) shell and n is the number of
electrons in this shell (Samsonov, 1956). A similar variation in the
lattice energy and the hardness with acceptor ability of metallic
compounds takes place. Also, the work function of the electrons in the
case of thermionic emission rises and electrical resistivity drops with
an increase in V^j^ (Samsonov and Neshpor, 1959). The electron density
of the bonds also varies vrlth the ionisation energies of the non-
metal atoms; their capacity to donate electrons rises in the direction
0,N,C,B,Si- This view is repudiated by Rundle (I9U8), but Schwarzkopf
. and Kieffer (1953) hold that vrith lighter atoms in refractory materials,
assuming metallic state, fairly strong metal to non-metal bonds can be
formed. The Ubbelohde-Samsonov theory leads to comprehensive and
quantitative explanation of physicsuL and chemical behaviour. Its scope
in rationalising the up-to-date information for borides and carbides is
illustrated now; types of experimental information leading to its
applicability are indicated.
2.6 Properties of borides and carbides
Properties of borides and carbides have been discussed by Shaffer
St Samsonov (I96ii), Campbell et al (I9h9), Samsonov & Golubeva (1956),
Munster (1959), McDonald & Ansley (1959), Webb et al (1956), Aronsson
(1960), Stewart & Cutler (1967), Thompson & Wood (1963), Thompson (1965,
1970a, 1970b, 1970c), Storms (1967, 1972), Toth (1971), Kosolapova (1971),
and Glasson it. Jones (1969a), Table 2.2^ summarises more recent invest•
igations on the various aspects of the properties of borides,
2.7 Sintering of borides and carbides
The duration of sintering in the formation of borides and carbides
and their subsequent calcination affects to a large extent their
• 25 Table 2.h
Boride Property Reference
General, reaction with Markovskii et al, 1969 HCl and HNO^
Scandixim and yttrium NMR spectrum Barnes et al, 1970 borides
ZrB2 Thermal conductivity Neshpor et al, 1970a
TiB2, ZrB^, HfB2 Thermal diffusivities Branscombe & Hunter, 1971
Nb^B2, NbB, Nb^B^^, Physical properties Kovenskaya & Serebryakova, 1970 NbBg
IVA-VA metal borides Thermal expansion Samsonov et at, 1971a
TiB2, ZrB2, HfB2, Thermal expansion Keihn & Keplin, 1967 NbB2,.TaB2
Transition metal Heat capacity Kuentzler, 1970a, 1971 borides
CrB2 Calorimetric and Castaing, 1972 resistive magnetic properties
HfB2 Chemical stability SavitskU et al, 1970a with HGl, H2S0^, HCIO^, HNO^, NH^Cl + HCl, CH^COOH, H2O2, My Air
TiB2, ZrB2, VB2, Chemical stability Kxzgai & Nazarchuck towards HCl, HCl + 1971a HfB2, NbB2, TaB2 H2O2, HCl + H2C20^, H2S0^ + H2O2, H2S0^ + H2C20^, HNO^, H2O2, H2O, H2C20^
Zr02 - ZrB2 Reactions at 1000 - Marek et al, 1971 2000°C Hf02 - HfB2 Nb20^ - NbB2 Ta20^ - TaB2 Cr20^ - CrB2
26 TABIE 2M (cont'd)
Boride Prope rty Reference
Borides of transition Reaction with BaCO^ Kugai & Nazarchuck, ' 1971b metals TiB2, ^rB^y or Ca CrB^, M0B2
Molybdenum and tungsten Stability, acid Kugai, 1971 borides
SrB^ - LaB^, Thermionic properties Bliznakov fic Peshev, 1970 BaB^'- LaB^
Niobium, tantalum, moly• Resistance against Samsonov et al, 1970a bdenum and tungsten carbonizing borides
TiB2, ZrB2, HfB2, VB2, Heat treatment with Levenskii et al, 1968 carbon NbBg, TaB2, CrB2, MoB, M02B^, Vm, W2B^
TiB2, V;2Bj, (Ti, Cr) V/ear resistance Oreshkin et al, 1971 boride
Cobalt and nickel Stability to carbon Markovskii et al, 1971 borides
LaB^ Interaction vrLth moly• Cert et al, 1969 bdenum, tantalum and graphite
LaB^, CeB^, PrB^ Resistance to H2O, Kosolapova & Domasevich, 1970 NdB^ alkalies and acids
IB^, SrB^, LaB^, Magnetic susceptib• Etourneau et al, 1970 ility thermoelectric ThB^ power, specific heat
LaB^, NdB^, SmB^, Oxidation in air Timofeeva & Timofeeva, 1971 DyB^
SmB^ Reaction with nickel • Romashov et al, 1970
Borides in general Systematic phase chem• Vekshina & Markovskii, ical analysis 1969
FeB, Fe2B Effect of temperature Kunitskii & Marek, 1971 on physical properties
27 TABLE 2.U (cont'd)
Boride Property Reference
FeB,.Fe2B Re sistivity, thermo-^ Kostetskii et al, 1971 emf, thermal conduct• ivity and expsinsion 70 - I3OOK
FeB, Fe^B Anisotropy of thermal Lyakhovich et al, 1971 expansion
(Fe-Co) boride, Heat capacity Kuentzler, 1970b CCo-Ni) boride
Rh^B^, RhB^ -j^ Hardness Kosenko et al, 1971
Borides in general Fusion and heat Pastor, 1969 compression
Boron-coated metal Mechanical properties Ducrot & Poulain, 1970 objects
AlB,o Crystal structure and Will, 1970 electron distribution
ZrBg - Mo Structural properties Kislyi ^ Kuzenkova, 1966
Nb^Bg, NbB, Nb-B^, Electrical resistance, Samsoriov- et al, 1971b thermo electric pot• NbB^, Cr^B, Cr-jB2, ential, A'l/ , Hall CrB, Cr^B^, CrB2 co-efficienx
IrB^ 35, IrB^ •Crystal structure Rogl et al, 1971 ^^^0.9 SmB^ Electronic configiir- R:/ne, 1970 ation, magnetic and Cohen et al, 1970 electric properties
General borides Role of valence Sleptsov fie Kosolapova, . electrons 1970
28 Tables 2.h (cont'd)
Carbides and mixed borides
Carbide Property Reference
ZrC Hot hardness Savitskii et al, 1970b
Transition metal Abrasive- wear Artamonov & Bovkun, 1970 .carbides
MeC and Me(C,N) of Systematic chemical and Georgieva et al, 1969 group IVA & VA electrochemical separ• ation
Carbides in general Systematic phase chem• Vekshina & Markovskii, ical analysis 1969
Interaction with C • X Srborbran, 1969 (fluorides, V20^, MgO, Al20^, SiO^)
Pyrolytic B^^C Electrical resistance, Neshpor et al, 1970b e,m.f., thermal con• ductivity and micro-• hardness
Optical properties Werheit et al, 1971
Cr^C2 - B^C, Interaction in weld• Oreshkin et al, 1970 ing B^C - SiC, Cr^C2 - SiC
Diboride-nitride Dry friction and wear Medvedev & Sin,kov, system 1971
Crystal structure and V/ill, 1970 * V^^2ii electron distribution
/ - VC, /-NbC, Crystal structure Yvon & Parthe, 1970 J - TaC
Carbides in general Properties of car• Samsonov, 1970 bides based on electronic config• uration
. 29 chemical reactivity. Extensive studies on the sintering of oxides and to a lesser extent of nitrides have been made (Glasson fit
Jayatieera, 1968). Theories of sintering have been established by
Huttig (19i4l), Kingery (1960), Coble (1961, 196U), Kuczynski (1961),
VJhite (1965) and Fedorchenko & Skorokhod (1967). The rate of
sintering is considerably increased by pressing the povfdered materials
before calcining in vacuo to stop hydrolysis and oxidation (Chiotti,
1952; Gegiizin fic Partskaya, 1967).
Materials (Schwarzkopf fic Kieffer, 1953) can be compacted and
pressed to almost theoretical densities by hot pressing them, e.g.
oxides such as MgO, CaO, Al20^ (Carruthers fic Wheat, 1965; V/heat fic
Carruthers, 1961). Small amounts of impurities, especially those
giving rise to gaseous products such as hydroxides and carbonates
hinder the sintering. In the presence of nitrogen, carbides are
converted to carbide-nitride solid solutions, e.g. TiC (Zelikman &
Loseva, 19U7; Zelikman fic Gorovits, 1950) and ZrC (Duwez £c Odell, 1950).
Hot pressing is often carried out in vacuum to avoid such contaminations
(Glasson, 1967). Small quantities of low-melting additives generally •
increase the rate of sintering (Glasson, 1967) iisually at the cost of
excellent optical and mechanical properties. Cermets (Schv^arzkopf &
Kieffer, 1960) or surface coatings having superior properties may be
obtained by sintering very brittle borides and carbides vri.th metals
such as cobalt (Povrell et al, 1966).
2,7.1 General principles of the mechanism of sintering
and hot pressing
The process of sintering is that by which povrders are consolid•
ated into strong, and usually dense polycrystalline aggregates by
30 heating. Systems undergoing sintering are of tvjo types, namely:
(i) Homogeneous systems consisting of a single component
•
or components T^ich give continuous series of solid
solutions,
(ii) Heterogeneous systems consisting of multiple component
systems.
In the homogeneous sintering of a poi-rder, distinction can be
made betx-reen tx^o overlapping stages of sintering. The first stage is
characterized by the formation and grovrth of bonds, i,e, the contact
areas betv/een adjacent powder particles- The growth of these contact
areas takes place during the early stages of sintering, v:hen the
material is densified and the pore volume decreased. Under favourable
conditions the pores are practically eliminated. The surface free
energy is considered to be the driving force in both stages of
sintering- The energy reqioired for sintering is supplied by the
decrease of surface areas or by the- replacement of high-energy inter•
facings by those of lovrer energy, e.g. grain boundaries- The surface
free energy is sufficient-to account for sintering, provided a suitable
mechanism is available for the transport of atoms involved in the
consolidation of powder compacts- The following five mechanisms are
possible in the case of homogeneous materials:
(i) Evaporation follovjed by condensation.
(ii) Siirface diffusion.
(ii±) Volume diffusion.
(iv) Viscous flow (Newtonian flow characterized by a linear
relationship between strain rate and stress),
(v) Plastic flow (Bingham flow characterized by the existence
of a yield stress).
31 Different theories of sintering and mechanisms of material and pore transport have attracted much attention of workers in the field of sintering, Alexander et al (I9ii5), Herring (1950), Kingeiy et al
(1955), Murray et al (195^1), Nabarro (I9ii8). The sintering of B^C and other refractory materials has been reviewed comprehensively by Jones
(1970). Points arising from this review and recent advances in the technology of sintering are presented here-
2.7.2 Role of volume. Grain boxindary and Surface diffusion
The role of volume, grain boiindary and surface diffusion during the initial, intermediate and final stages of sintering has been studied by Ristic (1969). Separate equations for all three mechanisms have been formulated. His model for the initial stages, of sintering, based on the shrinkage of a vdre on a plane, shows considerable
discrepancy from the solutions proposed by earlier authors- Accord•
ingly, a solution for an infinite line has been suggested.' Comparison
of results regarded in the context of some other indicators shovrs that
surface diffusion is responsible for the mechanism of the process in
both cases. The intermediate and final stages of sintering are often
directly responsible for the physical properties of a sintered body.
The equations for models vrhose systems are composed of units consisting
of either cubes, hexagonal prisms, dodecahedrons, or tetrakaidecahedron
are given as:-
(a) Bulk diffusion model
P. = K^D^o^^f-*) I l^kT •: .
(b) Boiindary diffusion model 2/3
11
32 where
p = the volume fraction of the pore c D = bulk diffusion coefficient
% = surface energy- 4 = vacancy volume t = time
time at v/hich the pore vanishes ^f = \ boundary diffusion coefficient 1 = edge of the polyhedron
w = boundary width
= constants
k Boltzmann constant
T thermodynamic temperature
A comparison of and v/ith Coble's model clearly shows the influence of the. geometry on densification during intermediate and final stages of sintering. Accordingly it is possible to determine the critical size of the specimen by means of the equation:
HI
- vacancy diffusion coefficient
t = time
The role of non-stoichiometry in the sintering of ionic solids has been studied by Reijnen (1969). This work deals only with the volume diffusion of vacancies and interstitials, specifically with the flux of vacancies emitted by spherical pores,
Johnson (1969a, 1969b, 1969c, 1970, 1971) has studied extensively the new methods of obtaining volume, grain-boundary and surface diffxision coefficients from sintering data, sintering kinetics for
33 con±»ined voliane, grain boundary and surface diffusions, the inter• mediate stage of sintering and the methods of determining sintering mechanisms. His model for the determination of sintering is given in Fig- 2.5. J-
Fig. 2.g Geometry and atom flux paths for initial
stage model. A, B and C are volume diffusion, D is
grain boundary diffusion, E is surface diffusion, and
F is vapor transport.
(After Johnson, 1971)
It is based on the assumption that all densif ication is produced by diffusion of atoms from the grain boundary between the particles to the neck surface, by volume or grain boixndary diffusion or by both processes acting simultaneously. It is assumed that vacancies are at equilibrium concentration everyivhere and that the surface and* grain boundary tensions are isotropic. The sintering equation is given by:-
y = 2y-a.D^ . _ + ht-^ hU^ IV X + R coso^ X kTa- kTa where
X = fractional neck radius
R = normalized minimum radius of curvature of neck surface
^ = as defined in Fig. 2.5
y = fractional shrinkage AI/L
3U y shrinkage rate surface tension
atomic volume
vol\ime diffusion constant
A normalized area of neck surface
b grain-boiindary width
boundary self-diffusion coefficient
a sphere radius
k . Boltzmann constant
T thermodynamic temperature
. If it is assumed that there is no mass transport from the particle surface to the neck surface, and li is zero, then all of the geometric parameters can be related to the shrinkage as follows:
2. 2.1i8}C-n- D__ + 0.78y-/l-bD^ y y KTa-' kTa'*
If it is assuned further that either grain-boundary diffusion or volume diffusion only occurs, then the folloijing simplifications of equation IV resiilt. For volume diffusion :-
1 - 2.ii8V-n-D VI V y kTa-
Tyy 2.ii8y-n-D
ka- and for grain boundary diffiision;
A - 0,78XA-bD^ \ ^ ^-i VH
Ty y = 0.78y-^bD, VIII ka-*
During the intermediate stage of sintering the individual
35 particles at the beginning have more or less lost their identity. The pores are interconnected by channels lying along three grain inter• sections- The densification mechanisms are the same as those that occiir during the initial stage but the geometry is more complex- Because of geometric complexities of the compact, a method of averaging 'the significant geometric parameters is employed, The resulting equation is
G dV = 32^-^ ^ S^ + 32<-^D^ ^ .dt HL^ V'"^ kT kT where
G = mean grain diameter
H =• average mean surface curvature
= length per unit volume of intersection between
grain boundaries and pores
S^ = pore surface area per unit volume
V = instantaneous volume of compact
Equation IX is an attempt to analyse sintering data when all changes in the mechanism of mass and pores transport and geometric factors occur. It has been modified further for various states of sintering and for isothermal and non-isothermal sintering,
2.7.3 Role of dislocations
Investigations of sintering processes have included occasionally efforts to observe dislocation motion during sintering- These efforts have been unsuccessful.' Hovrever, this does not mean that dislocation motion does not contribute to the sintering process* Due to the nature of dislocation slip, it is probable that actual observations of moving dislocations during sintering may be extremely difficult or impossible.
The reason is that dislocation generation and motion during sintering
36 occur most readily in very small particles or crystallites. In small crystals, dislocation generation a-Jill be at the grain boundary, leaving little opportunity for dislocations to be seen by transmission microscopy. The dislocation motion occurs in large particles, where
the stress to cause sintering is less only at very high temperatiires, irtiich are probably not avilable iinder the conditions when the microscope
is in use. Dislocations can remain in the. crystals under certain
conditions involving short heating periods. The role of dislocations
in the densification of CoO arid NiO vri.th a dispersion of MgO or'CaO
has been studied by Tikkanen and Ylasaari (1969). The dislocations
in high-temperatxire sintering have been observed by Morgan (1971)-
A comprehensive review based on theoretical and experimental invest•
igations on bubble raft sintering, dislocation nucleation in necks,
kinetics of sintering and distinction in the role of dislocations and
diffusion flov: during sintering has been given by Lenel et al (1971)
and Lenel (1972).
2.7.[i Role of atmospheric effects
The atmosphere has an effect on both surface tension and
diffusivities. Absorption of gas atoms on metal surfaces lowers the
surface tension, while the surface diffusivity is either increased or
decreased. The effect of dissolved gas atoms on the voliime seLf-
diffusivity is generally quite small. No direct information is avail•
able on the atmospheric effect on grain boundary diffusivity. Two
effects, which gases trapped at closed pores might exert on the course
of microstructure development, have been studied q\iantitatively (Coble,
1969). The first relates to a change in pore shape, the second to gas
solubility.
37 Becaxase there are few data for gas solubilities or diffusivities in metals or ceramics, there are only few instances for vriiich the final stage of densification can be modelled quantitatively. A comprehensive mathematical treatment of the atmospheric effect on the density decrease with pore coalescense, cylindrical pore equilibration and spheroidization, equilibrium of pore voliimes, break up of cylindrical pores to spherical pores ,and gas solubility, has been presented by Coble (1969).
An interesting problem is the interaction betvreen material trans-
port iTEchanisms that contribute to surface rounding only, and those
^ich cause densification. The effect of atmosphere on the interaction
of two opposing types of material transport mechanism has been studied
by Gessinger (1971) using Ag and Fe as model materials. The results
are given by tvjo eqiiations:- D X. 0.61 s ^ X s X V 6 V GB 6 ^
where x = rate of sxirface diffusion s
±^ = rate of volume diffusion
= rate of grain boundary diffusion
Xjj^ = rate of self-diffusivity
Dg = surface diffusivity
= volxame self-diffusivity
= grain boundary diffusivity
J' = surface tension
In Fig. 2.6 the neck profile reqiiired to allow distribution
of atoms coming from grain boundary sources is drawn. Only
a change in the sign of the curvature would permit such a
33 • Fig. 2.6
Neck profile with sign Neck profile viith same change in neck curvature sign of curvature
surface diffusion fliix
grain boundary flux GB outward surface diffusion flux
volume cUffusion flux 'DV (After Gessinger, 1971)
39 hypothetical case, in which surface diffusion could then be densific- ation rate controlling. Due to this convex neck area element, the driving force for shrinkage would, hoi-rever, be reduced to practically zero. In Fig. 2.6 material from the grain boundary is diffusing along the grain boundary in the direction of the neck surface, but is then
channelled through the volvmie near the surface. Siirface diffusion
can now proceed from the particle sxirface to the grain boundary groove
at the neck, since the gradient of chemical potential along the surface
is unidirectional. This model would predict that voliioie diffusion is
the rate-controlling step in densification and that the effect would be
most pronounced vjhen volume diffusion is very, slow as compared xriith
grain boundary diffusion.
A mathematical model of sintering has been developed by Tukamoto
et al (1970) in x-jhich considerations have been given to drying processes
of solids, the composition of limestone and the melting and solidifying
process of iron ore. Partial differential equations giving numerical
values of various parameters have been derived.
2.7.5 Computer-simulated models of sintering
A dynamic volxome diffusion model for sintering has been presented
using the Laplace equation by Easterling et al (1970). Computed
profiles and charts of chemical potential changes are printed out
directly. Assuming that there are no internal sources and sinks of
vacancies, the chemical potential,^ , of vacancy diffusion can be found by solving the Laplace equation:
+ ^Jl Xll —r "2 = ° ^y The only boundary values needed for the case of volume diffusion
are:
ho JUi ^ 'f Ua. at the neck P ^ P 1LQ_ elsewhere on the surface a where 5^ = surface tension
tLcC- atomic volume intermediate values can be found by the relaxation grid technique. It
can be shoi-m that:
U .
Initially, x-rith only boundary values to work on^ the process of
calculating the potential distribution is a procedure of iteration.
The changes in chemical potential and model profile have been calctilated
using an IBM 360 computer by this author.
The effects of operating-variables, i.e. temperatxire and oxygen '
concentration of gas in ignition furnace, time for ignition, mass
velocity of gas, diameter and temperature of solid particles to be fed,
on the temperature distribution in the sintering bed have been estimated
by Muchi and Higuchi (1970) using numerical techniques with the aid of
a computer.
2.7.6 Reaction pressing and pressiire sintering
Reaction pressing is based on the fact that many intermetallic
compounds can be formed from their constituent elements'* x^ith rapid
evolution of a substantial quantity of heat. This exotherm is often
sufficient to render the reaction change. The nascent compound has a
transient plasticity so that, provided pressure is applied through a
fast-acting system capable of keeping pace with rapid reaction-
contraction, a product can be synthesized and shaped quickly
and relatively easily at an initiating ten$)erature that is low in
relation to conventional fabrication temperatures. Stringer & V/illiams
hi (196?) have demonstrated the superiority of i*eaction pressing over other methods of fabrication. High melting materials, such as borides, cai'bides, nitrides and silicides as well as oxides and cermets, cannot be compacted to dense pore-free bodies by cold pressing and ordinary sintering. By pressure sintering, on the other hand, it is possible to produce bodies vri.th greater than 9^% theoretical densities. Janes Sc.
Nixdorf (1969) have compared the tv;o methods of compaction and have shown consolidation to be a fxinction of pressure, temperature and time.
A new predictive densification equation of pressure sintering during the final stage of sintering has been proposed by Shimohira (1971) -
It is based on polyhedral space-filling bodies. If the size of contact area can be expressed as a function of porosity, f (P) then the effective stress ( i ), i.e., the compressive stress, maybe formulated as: e
where = applied stress
f(P) = function of porosity
A general expression'for contact area per polyhedra from geometric considerations is:
A = S(l - k jP. ^) X7(a) irtiere s = constant equal to total area of polyhedra at zero porosity
k = constant
ip- = porosity
In a simplified form, - 3/2 A = (1 - P) when P less than 0,3 XVI 3/2
A linear relationship between A and (1 - P) therefore wo\ild be expected. The effective stress may be given as: ^e = <^a/ ® ^(1 - ?) XVll
U2 An isothermal densification equation, derived from a combination of Nabarro-Herring diffusion creep equation and the effective stress, is given as:-
dp/dt = 10 <^ ^-VR^kTpi mil or p ^ ^ ^0 i^^-n-/2R^kT + constant HX
An apparatus for the automatic measurement of shrinkage during sintering has been developed by Vydrevich (1970). It was used for shrinkage measurement dxiring the sintering kinetics of txingsten powders with small nickel additions. The following empirical formula has been obtained
^o where -^L/L^ = shrinkage
t = tijne
A,b& c = constant
Zaverukha (1970) has investigated the sintering process on the
basis of changes in the electrical properties of compacts on heating.
Lindroos (1971) has reported the annihilation of vacancies by
small angle grain boundaries during sintering. Pore shape changes
during the initial stages of sintering of copper powders has been
studied by scanning electron microscopy by Kellam et^al (1971)'
2.7.7 Effect of vretting on'sintering
2.7.7.1 General principles
V/etting is a phenomenon that arises whenever two different
phases come into contact. It depends on the contact angle betv/een
the phases. In sintering processes, the most common systems are
solid-solid, solid-gas, and solid-liquid. Only solid-liquid systems
h3 are dealt with in this section. VJetting is an extremely complex process at high temperatures, and a more comprehensive treatment would be too wide- The solid-liquid and solid-solid sj''stems are of most interest in powder metallurgy and sintering technology, as well as in producing fibre-reinforced materials.
Experience of the development of powdered metal substances based on hard metals, e.g. tungsten, tantalum, molybdenum, niobiiim, where an interesting combination of properties can be provided by using metals in the iron group as the cementing phase.
The sintering process is the principal technological oper• ation vjhich decides the properties of the finished product. It takes place, in this case, in the presence of a liquid phase which binds the grains of the high-melting compound and of the
cementing metal; the latter effectively wets the solid phase.
The bonding effect is much greater vAien there is limited mutual
solubility within the system consisting of the high-iralting
compound and the "cementing" metal (Kermety, 1962). A consider•
able amount of information has now been accumulated as to the wettability of hard high-melting compounds by molten metals
(Naidich,196U; Naidich & Lavrienko, 1965; Eremenko & Naidich,
1959).
This discussion deals vjith metal boride-metal and metal
carbide-nBtal systems. These classes represent systems used
extensively in the production of »hard metals' , which were
originally discovered and developed on purely en^irical grounds,
and whose theoretical principles are still not fully understood.
Multiphase materials of this type are produced throiigh
ill; powder-metallurgical techniques, because conventional methods would not give an equal distribution of the various phases.
The choice of system must take into account the properties required for the final product, e.g. density, wetting and non-porous homogeneous character.
A comprehensive treatment of wetting problems in connection with sintering is given by Tikkanen et al (1971)- They begin their discussion with the Young-Dopr^ eqxiation: ... V = Y ^ + dos e XXI fic^'s v °sl Iv where )f^^ = solid-vapour interfacial energy (surface tension)
= solid-liquid n • it ( u n )
V^^ = liquid-vapour " " ( " " )
0 = contact angle
The limitation of this equation and the definition of the
terms in it are discussed-
Q is a measure of the degree of wetting and is the only
characteristic quantity that can be measin*ed conveniently. The
effect on 5:;6f varying each value of ^ can be derived from
equation XXI, and is summarised by Tikkanen et al (1971)-
Since the surface tension of the metals concerned is
always appreciably higher than that of the chemically-stable
borides and carbides, it is impossible to have complete wetting
between these two important groups of materials if sintering is
carried out in a neutral atmosphere. Tikkanen et al (1971)
define also a term, the spreading co-efficient, S^^ in terms of
surface tension values. They also give equations to calculate
the binding force between two phases.. 2.7.7-2 Wetting problems in the sintering of borides
and carbides T-rLth metals
The refractory borides and carbides of the transition metals are used to make cermets. A metal or alloy which forms the plastic component is in the liquid state during fabrication so that the v/etting of a solid ceramic by this liquid is important in ensuring that the product has the required propert• ies.
The metal boride and carbide systems are' those v/ith the greatest practical significance. Recently research in this field has been intensified considerably. The effect is related to the larger numbers of free valency electrons in the solid metal surface and metal-boron bond strength.
In general,carbides-wet transition metals more than borides
According to Rang, the more stable the carbide the poorer the
wetting. The stoichiometric defect structure of carbides plays
an important role in this context. Hovrever, there is little •
quantitative information available.
The wetting between a metal and carbide can be altered by
making suitable additions. For exan^le, wetting between nickel •
and TiC is considerably improved by molybdenum; the latter -being
a povjerful carbide former, reacts with TiC and is dissolved in
the TiC phase (Tikkanen et al, 1971).
The sintering of ZrB2 with W has been studied by Kisliy
(1971). Shrinkage measurements with time show the formation of
solid solutions of W in ZrB2 as vjell as new phases, W^B,
(VJ,Zr)B,
The contact angles of molten metals with refractory borides
and carlDides are tabiilated in Table 2.5.
I16 - TABLE 2.5
COmCT ANGLES OF SOME MOLTEN METALS WITH REFRACTORY BORON CQt4P0UNDS
Phase Metal Temperature Reference
Zn ShO - 620. 121.5 - 119 Samsonov (1960)
Cu 995 - 1,090 130 - 17
Al 600 . 670 117 - 118
Al + 1.39 Mg 8U0 115 Manning et al (1969)
Al + 9.98 Mg 115 - llli
Al + 1.62 Cu 150
Al + 9.82 Cu 138
Al + 2.58 Si liiO
Al + 10.38 Si 120 - 121
Fb 225 - 395 121 - 113 Samsonov (I96O)
Brass 905 - 950 5U.5 - 30
Fe 1,780 strong Kami j an (1952) Reaction
Co n 90
Cr 1,820 - 1,830 0 Janes & Nijcdorf (1969)
n - Cr/Ni l,liOO - i,Uio 0
Ni 1,U70 hi
TiB, Cu 1,500 158 Eremenko (1959) 1,083 . (10" lO'^mm.Hg) 158 Tumanov et al (1970)
Ni 1,U8G 100 - 38.5 Eremenko (1959)
hi TABLE 2.5 (Cont'd)
Phase Metal Temperature 6 . Reference
TiB^ Ni i,U55 - (10'^ - 10"^mm.Hg) U6 Tumanov et at (1970)
II Al 9$0 - 1,000 Panasyuk et al (1971)
II ti 950 - 50 85 - 150 If
II It 1,250 90-32 It
II Ag 1,100 - 1,600 120 - 100 Vatolin et al (1969)
ZrB^ Cu 1,100 . 60 Panasyuk et al (1969)
II Ag 1,100 - 1,600 116 - 83 Vatolin et al (1969)
Cu 1,300 - 1,350 lii5 Panasjruk et al (1971)
11 Ag 1,100 - 1,600 109 - 87 Vatolin et al (1969)
NbB2 Cu i,U5o 125 Panasyuk et al (1971)
tt Ni Metal does melt at 1,550. The II surface of the boride under the nickel is corroded
TaB^ Cu 1,100 50 Panasyuk et al (1971)
ti Ni 1,U80 1x3 - 60 . II
CrB Cu 1,083 ko Tumanov et al (1970) (10"^ - 10"^mm.Hg)
11 Ni 1,U55 * 0 ti (10~^ - 10"^mm.Hg)
U8 TABLE 2.5 (Cont'd)
Phase Metal Temperatiire e Reference
CrB^ Cu 1,083 51 • Ttmianov et al (1970) (10"^ - 10"^mm.Hg)
tt Ni i,U55 • • 111 II (10"^ - 10"^mm.Hg)
II Cu - 115 Panasyuk et al (1971)
... M0B2 Cu 1,100*- 1,500 8 II
» Ni l,ii80 8 - 15 It
VfgB Ni 1,200 - 1,U00 25 -. 16.5 Kiparisov (1970)
Cu 1,083 21 Tumanov et al (1970)
n Ni i,a55 0 It
V/B2 Cu 1,083 1*0 Yasinskaya (I966)
Tie Bi 300 - 700 138 - 118 lavey 5c Mxirray (1956)
ft Pb iiOO - 1,000 152 - 90 II
ft Ag 980 108 II
ti Al 700 118 Belyaev & Zhemcluz- hina (1952)
ft Al 900 - 1,000 lli2 Panasyuk et al (1971)
II Al 1,250 85 - 20 II
n Zn 550 120 Belyaev & Zhemcluz- • hina (1952)
11 Cu 1,100 - 1,300 108 - 70 Livey & Murray (1956)
1x9 TABIE 2.5 (Cont'd)
Phase Metal Temperature ' Reference °C
ZrC Cu 1,100 - 1,500 lliO - 118 Livey & Murray (1956)
VC Na 200 - Uoo 160 - 9
ri Cu 1,100 Sh .
WC Bi 500 - 1,200 150 - 80
Sn 500. - 1,200 120 -•50
uc Na 200 - hOO 162 - 122
It Bi 300 - 1,700 lliO - 95
IT Cu 1,100 - 1,260 113 - 70
50 2.8 Industrial applications of borides and carbides
The applications of borides and carbides in industry have been
revievred by Aronsson (I96O), Thompson (1963, 1965), Storms (1967,
1972), Toth (1971) and Kosolapova (1971). Table 2.6 summarises more
recent references to such applications. These are tabulated under the
following headings:
1. Refractory materials. .
2. Corrosion-resistant materials as for the chemical industry,
3. Materials for nuclear energy production.
U. Manufacturing materials for aircraft and rockets.
5. Materials for the electronics industry.
6. Super-hard and vjear-resistant materials.
Biddulph, Matterson & Brox-m (1973) are working on commercial
scale applications of boronised objects. Boronised components can be
used to advantage in shot blasting equipment, in jigs for industrial
polishing, and in machines for handling abrasive dry materials in the
chemical industry. In hot dip galvanising and zinc-die-casting xise is
made of. the boronised layer?s resistance to attack by molten zinc.
Boronising increases life of WC/Co by 250?.
Potential applications for boronising, vrhere the advantage of
the wear resistance of the hard layer would be usefiil, are numerous-
For example, in dies and plungers for compacting abrasive powders such
as those used in the powder metallurgical industry, the ceramic
industry and in the manufactvire of pelletised catalysts. Other potential
applications are for chain conveyor parts v/hich are subjected to
abrasive dust, for bearing surfaces on shafts, especially those subjected
to abrasive wear, and for earth-moving equipment.
51 TABLE 2.6
Feature Phases Principal Properties Fields of Application Reference
Refractory TiB Oxidation reaistant, very hard For coating on graphite to pro• Burykina, 1970 materials TiBg + TiC and wear resistant tect against oxidation
TiC Extremely hard and wear resist• As neutron moderator for Whittemore, 1968 ant reactors
TiC Wear and abrasive resistant, Jet mill components Dan'kin, 1970 high microhardness
TiC Hot extruded (worked), high NASA Aerospace applications Gangler, 1971 hardness and hard strength
TiC (Cermet Resistant to molten Na and Parts of pumps for transferring Kosolapova, 1971 TiC-W) Na-K alloys at .high temperat• Na ures (l050^C)«and pressures up to 861 W-Ji (8.5 atm)
ZrBg Wear and abrasive resistant, Jet mill components Dan*kin, 1970 high microhardness
ZrC Resistance to molten metals ' Crucibles and boats for Kosolapova, 1971 melting metals, tubes for con• veying molten metals
ZrBg + ZrC Oxidation resistant, high For coating on graphite to pro• Burykina, 1970 hardness and wear resistant tect against oxidation
HfC High melting point, resistant In composition of special Kosolapova, 1971 to molten metals refractories for lining cruc• ibles for melting metals TABIE 2.6 (Cont'd)
Feature Phases Principal Properties Fields of App3-ication Reference
HfC Very high temperature melting As incandescent lamps for film Whittemore, 1968 point compound 7,100 F
NbC Resistant to molten metals Crucibles and boats for melting Kosolapova, 1971 metals, tubes for conveying molten metals
NbC Parts of plant for evaporating Al and Zn
NbC Hot extruded (worked), high NASA Aerospace applications Gangler, 1971 hardness and bend strength
TaC High melting point 7,100^ As incandescent lamps for film Whittemore, 1968
TaC Resistance to molten metals Parts of plant for evaporating Kosolapova, 1971 Al and Zn
TaC High melting point, resist• In composition of special Kosolapova, 1971 ance to molten metals refractories for lining cruc• ibles for. melting metals
WC Extremely hard and wear As component of cutting tools Kosolapova, 1971 resistant
Hardest and most abrasion Sand-blasting nozzle, for Whittemore, 1968 resistant material, high control and shielding in * neutron-capture cross-section. nuclear reactors, for the High strength and elasticity, formation, of personnel body low density armour TABLE 2.6 (Cont'd)
Feature Phases Princiffai Properties Fields of.Application Reference
As indenter for studying micro- Skuratovskii, V hardness of materials 1969
SiC Very hard, resistant to As heating element for furnaces Whittemore, 1968 oxidation (2800°F) (3P00?F) low thermal expansion Abrasive grinding and cutting • ti high thermal conductivity of wheels
SiC alloys Resistance to molten metals Parts of plant for conveying Kosolappva, 1971 molten Al, linings for baths for the production of Al by electrolysis of molten salts, crucibles for melting non- ferrous and rare metals, protective thermocouple sheaths
Corrosion- TiB^ Resistant to non-ferrous metals For handling molten Pb, Sn, Thompson & Wood, resistant ZrBp and chemical attack at high Zn, Mg, Al, Cu, pump impellers, 1963 materials CrBg temperatures, high electrical tyres, galvanizing bath com• for the conductivity, hardness, oxid• ponents, thermocouple sheaths, chemical ation resistant, high thermal troughs chutes, and level industry- conductivity indicators in non-ferrous metals, vaporising boats, crucibles for the vacuum eva• poration of thermal, electri• cal contacts, space technology, heat exchangers TABIE 2.6 (ContM)
Feature Phases Principal Properties Fields of Application Reference
High resistance to various chem• Filters in chemical industry Kosolapova, 1971 ical reagents and resistance to electrodes for use in electro• oxidation chemical processes, bearings and packing in pumps supply• ing salt water londer high pressure for washing out oil tanks of tanker vessels, parts of pumps for conveying acids, nozzles for corrosive liquids and gases
Cr.C2,Cr C Catalytic properties Catalysts for use in organic tr Mo^C"^ ' ^ synthesis VA SiC High resistance to chemical Parts of pumps for transferr• reagents ing acid solutions, lining of nozzles for spraying corrosive II liquids, condensers and scrubbers working in corrosive gas atmospheres
Materials Be^C High melting points, strength Constituent of structural Kosolapova, 1971 for nuclear at elevated temperatures, materials, material for energy specific nuclear properties. retarders and biological production Addition of BepC to metallic- protection Be increases its long-term strength at temperatures of 650-700°C
ZrC High melting point, low Coating for graphite materials neutron-capture cross-section containing UC and ThC used as tt fuel elements in the power reactors for closed-cycle gas turbines TABLE 2.6 (Cont'd)
Feature Phases Principal Properties Fields of Application Reference
NbC,TaC High melting point, chemical Coatings for dispersion fuel ele• Kosolapova, 1971 resistance ments vri-th graphite matrices to retain fission fragments.
UC High melting point and thermal Cores of fuel elements of nuclear conductivity, absence of phase reactors, fuel materials in transformations, specific reactors with sodium and organic nuclear properties heat carriers. UC-ThC alloys are used as fuel in gas-cooled reactors '
B-10 isotope forms 18.8? total Fast breeder reactor, the reactor Alliegro, 1970 VA B in B, C and has UOOO barn of 80»s contains the isotopicalOy ON cross-section enabling it to enriched boron-ten variety due to arrest themal neutrons this characteristic. Dosimeters for fast-breeder reactor and bomb tests. First commercial gas- cooled reactors powered in 1972 x-dth 330 megawatt has walls pro• duced from hot-pressed B, C or by carbon bonding a mixture of B^C and graphite.
Used for neutron reactor design tests, as powder in AlpO- pellets for poisons, widely used in nuclear field as a control poison or shielding element. Extremely stable ceramic material^ versatile for the demanding reactor applications TABLE 2.6 (Cont'd)
Feature Phases Principal Properties Fields of Application Reference
Large neutron capture cross- Absorbent material for regulating Kosolapova, 1971 section rods (BjC-Al, B, C-Al^O^, B. C- ZrB2, B||C-Zircoii alloy) ^
WC, TiC High melting point, hardness' Constituents of metallo-ceramic hard alloys ensuring higher and heat resistance, strength If at elevated temperatures, productivity in the metal-work• capacity for recrystallization ing, mining, coal, and petroleimi through molten metals industries, widely used hard alloys belong to the types KA, TK, WZ, FS and BK
Very hard, uniform, strength In the reactor, rocket nozzles, Cochran, 1970 'adherent coatings chemical reaction and process- vessels
Great hardness and abrasive Grinding and polishing hard Kosolapova, 1971 poire r materials, sharpening and fin• ishing of hard-metal tool blades, cutting elements of drilling bits and tools for machining .hard" materials, tools for turning up grinding x-xheels, sand spraying jets, gauges, dies for the rod drawing of abrasive materials
CrB, Cr^C Very hard and wear resistant Screw conveyor coatings Degtev, 1972 coatings TABIE 2.6 (Cont'd)
Feature Phases Principi^l Properties Fields of Application Reference
High melting point, hardness which Constituent of filler alloys Degtev, 1972 ^^3^2 is retained at elevated temperat• and also of hard alloys used ures, high chemical resistance- for nozzles, dies, high- temperature bearing, press dies for forming brass sections jets for sand spraying
CrC-Mo High threshhold of oxidation Coating on the piston rings Hyde, 1971 and wear-resistant at elevated used in internal combustion temperatures engines
Superhard and TiC Hard and'we ar-re s is tant Cutting tools Kieffer, 1970 wear-resist• ant materials ZrC High abrasive power Polishing materials Kosolapova, 1971
VC, NbC, TaC High melting point, hardness Alloying addition to hard alloys
and heat resistance based on TiC and WC addition of II VC increases tool life by 10- 210^, addition of 2% TaC to alloy BK6 increases the rate of machining cast-iron by 10$ TaC to TK-type alloys increases the rate of machining steel by 20$
NbC, TaC, Hard and wear-resistant Cutting tools Kieffer, 1970 WC-Co
TaC High emissive power High-intensity light source ti suitable for illumination for filming (Hi00 Im), coating on metallic tungsten and rhenium for special elements of rad• iation lamps. TABIE 2.6 (Cont'd)
Reference Principal Properties Fields of Application
1970 Component of standard low-ohmic Kieffer, ^^23^6 Metallic character of conduction, small temperature co-efficient of resistance working at 300- electrical resistivity ii00°C with nominal resistance values of 5-50
Nuclear rockets, space power Gangler, 1971 (80? ZrBp-SiC) Excellent oxidation resistance, strength,- and thermal shock systems, re-entry vehicles 56% ZrBp-lli? resistance in the temperature and aircraft engine components SiQ-C) i (a) carbon cloth range 1600-2 800''c as reinforcement; (b) nickel as • additive Clougherty, 1969 Improved fabricability and Nose caps, lifting re-entry ZrBp -f SiC leading edges, air breathing HfBg +'^SiC enhanced material properties, excellent thermal, physical engine components, rocket and mechanical properties- nozzle throats-
Constituent of electrodes for Kosolapova, 1971 Materials TiC High melting point and elect• rical conductivity, low the underwater oxy-electric for elect• cutting of steel, thermocouple evaporation rate rical and electrodes for measuring radio pur• temperatures up to 2000 C in poses reducing and neutral atmos• pheres and in vacuum TABIE 2.6 (Cont'd)
Fields of Application Reference Feat lire Phases Princip al Properties
Tests for use as electrodes for Whittemore> 1968 TiBg, ZrBg Electric resistance in the order of copper Al reduction. Intergranular corrosion and brittleness caused failure
Thermionic cathodes for electr• Kosolapova, 1971 ZrC High melting point, low evap• oration, high emission onic devices working in port• current density able eqiiipment under conditions of low vacuum and intensive ionic bomb^dment, constituent of cathodes (ZrC-UC) of thermi• onic converters of thermal energy into electrical energy
ON Cathode material that works It o ThC High emission current density, low work function of electrons stably at 1900°C for 900h
Heating elements of electric NbC, TaC High melting point, low vapour It tension at high temperatures, resistance furnaces working in metallic nature of conduction, reducing and neutral atmos• satisfactory mechancial pheres up to 3000°C strength
Structural materials used in Kosolapova, 1971 Materials BegC. Addition of Be^C to metallic aviation for manu• Be increases its long term facture of strength and fracture aircraft and resistance rockets TABIE 2.6 (Cont'd)
Fields of Application Reference Feature Phases Principal Properties
Constituent of cermets for use in TiC High melting point,-hardness and heat resistance, strength at gas-turbine blades, withstanding high temperatures very well the severe operating conditions experienced in air- • carft jet engines, components of friction disks for aircraft con• struction, protective coatings for rocket components. (ARB nozzles and leading parts.)
Nose caps and leading edges, to Kaufman, 1970 ZrBp + SiC Long time high temperature fabricate nuts and bolts ZrBg + SiC + C oxidation resistance, high strength, thermal conductivity
ON Bushings, rings and nozzles in Varzanov et al, SiC Highly resistant to abrasive, corrosive and erosive wear in machines and instruments 1969 aggressive media at normal and elevated temperatures
Grinding, polishing, and Kosolapova, 1971 SiC Great hardness and abrasive power abrasive parts 2.9 The present research
The relatively low thermodynamic stability of boron carbide and its ability to react with most metals or their oxides with or xri.thout the addition of B20^ make it a valxiable and most important source of boron in the formation of borides. Hovjever, although thermodynandcally feasible, these reactions may be kinetically unfavourable. Increased surface area in terms of decreased grain size and closer contact of particles brought about by pressing uniform mixtures has been found to promote the rate of solid state reactions as in reactive sintering. Thus, successful reactions of metal hydrides and carbides xjith boron (Glaser, 1952) for the formation of borides of Ti, 2r, Nb and Ta have been carried out by hot pressing the mixtures at temperatures 1500 - 2780^C. Similarly, borides of V, Cr, Mo and W have been produced by hot pressing at 1$00 - 3l80°C mixtures of boron and the respective metals or their hydrides or carbides. Likewise, hot pressing studies were later carried out for boron carbide with the respective metals or their hydrides and carbides. Cold pressing of B^C, some additives (Al, B, Si) and some binders (paraffin wax, evostick, stearic acid, cow-gum) followed by sintering at I8OO - 2200°C has been studied by James and Biddulph (1970). Biddulph (1970)has devised a system for hot pressing and hot pressed TiB^ at 2000^0 up to 97% theoretical .densities.
"^'In the present work, the formation of metal borides-and carbides
is studied at 1000 - 1800°C using very finely divided boron carbide and
metals in the form of powder and foil. The research consists initially
of a study of the chemical reactivity and subsequent sintering of finely-
divided boron carbide with powdered metal additives. Changes in phase
composition, surface area, average crystallite and aggregate sizes are to
be correlated with temperature and time of heating. Further information
62 on the sintering processes is obtained from the densification on hot pressing at 1000 - 2100*^C boron carbide and some metal borides and carbides.
This research is developed to study "the formation of metal boride and carbide coatings on metal surfaces, by reaction with finely- divided boron carbide at different temperatures (1000 - 1800°C). The micro structure of the coatings is examined to ascertain vrtiat changes have occurred in phase composition, crystallite and aggregate sizes * and microhardness compared with the initial metal surface.
It is hoped that optimum temperatures and times of heating can
be found vjhich produce coatings having good crystallinity and micro-
hardness, to prevent any possible galling of the metal surfaces.
Nevertheless, for many practical applications, the coatings must have
good resistance to oxidation at high temperatures. Thus, further
research must be- undertaken on the oxidation of boron carbide and some
metal borides and carbides, particularly with regard to the effects on
scaling resistance and the irdcrohardness of metal coatings containing
these materials.
63 CHAPTER 3
EXPERIMENTAL TECHNIQUES
This chapter contains an account of the experimental techniques
used in this research vxork. Included is a summary of the underlying
principles and procedures.
3.1 X-ray diffraction
Peiser et al (1960) have given a comprehensive summary of the
theory and practical applications of X-ray diffraction techniques.
3.1.1 X-ray generators
Diffraction studies in the present iiork were carried out on two
X-ray generators of different design, namely, (a) a Hilger & Watts unit
connected to a sealed tube containing the filament and target; and (b)
a Raymax 60 generator manufactured by Nevrton Victor Ltd. with the
facility that the target can be changed and the filament replaced, and
kept continuously pumped by an oil diffusion pump coupled to a rotary
vacuiun pump. The Hilger fit Watts generator has a stabilised X-ray output,
with the voltage and the filament current controlled to within 0.1^
for a copper target. The radiation used was copper , wavelength
1.5ii2£. V/here excessive fluorescence was caused by iron or chromium
in the test samples, molybdenum radiation (0-71lfi) with a zirconium
filter was used.
3.1.2 The Counter Diffractometer
The powder diffraction patterns were recorded to identify the
phase composition of crystalline substances, in two ways, (a) by a
photographic method; and (b) using an X-ray dif fractometer equipped
with counter and rate meter. For the photographic recording of
diffraction patterns, a Debye-Scherrer camera, of 9 cm diameter and
manufactured by Unicam Instruments Ltd., was used. A Solus-Schall
6U diffractometer (diameter 50 cm) vras fitted with a Berthold ionisation detector and connected to a Berthold disconnector ratemeter chart recorder. The procedures used are the ones established by other workers, e.g. Jayav/eera (1969).
The sample for diffractometer studies was suspended in acetone and the dispersion so formed transferred to a glass slide. The solvent v/as evaporated from suspension and the powder left behind usually adhered
to the slide. For non-adhesive specimens a paste of an adhesive in
acetone was used to set these properly on the glass slide.
The glass slide containing the sample vias mounted vertically at
the centre of the diffractometer and rotated at half the speed of the
detector. This arrangement kept the sample in a tangential position to
the circle defined by the collimator diaphragm, the centre of the sample
and the counter diaphragm. The angles of the diffracting positions were
indicated on the circular scale of the table as well as on the chart
recorder. The readings on the ratemeter and area surrounded by the
peaks on the chart varied according to the intensity of the diffracted
beams,
3,1.3 • X-ray line (or peak) broadening
Even with a perfect crystal some broadening of the reflections
occurs. This instrumental broadening is independent of pure diffraction
effects and arises from a variety of causes such as:-
(a) The diameter of the cylindrical specimen and the accuracy
of centering, if it is rotated.
(b) The diameter of the camera, and its distance from the X-ray
tube.
(c) The absorption of X-rays by the specimen.
65 (d) The pinhole size or slit system of the camera.
(e) The intensity distribution over the target of the X-ray
tube considered from the direction in which the X-rays
enter the camera.
Over and above all these instrumental broadenings, the width of X-ray lines may be increased by diffraction effects caused by small crystallite size, by lattice distortion and by structure faults, including inhomogeneities due to variable chemical composition. In order to account for broadening of X-ray reflections from small crystals^Bragg's law has to be extended to cover incomplete reinforce• ment of the waves scattered by successive lattice planes. For small crystals, especially below lOOoS edge length, the deviations from
Bragg's law may be quite large. For parallel monochromatic radiation and a point specimen the breadth of the line is given by
KTV t cos^ where /^e angular breadth of the line defined by half-peak vjidth
corrected to give the intrinsic broadening.
t = edge length of cubic crystal
7^ = wavelength of X-radiation
9 = the Bragg angle
K = a constant dependent on crystal symmetry
P» is estimated either from the recorder trace as the peak v/idth at half
the maximum after subtraction of the background radiation, or by using
the scaler and printout to give optimum statistical accuracy. This
formxila is valid experimentally only vrlth monochromatic radiation and
irtien there is no instrumental line broadening. In order to correct
for these factors the method due to Jones (1938) is used. In this
- 66 methodjthe X-ray diffraction lines of the structure under study (m-lines)
are compared with those produced by a standard (e.g. calcite) consisting
of larger perfect crystallites (s-lines). The observed integral
breadths of the lines are first corrected for the fact that they are
produced by the X |«X 2 CuKo( radiation, and then
corrected for instrumental broadening.. The broadening due to lattice
distortion is considered by Stokes & V\5.1son (I9UI1).
A general method independent of simplifying assumptions, for
correcting the above factors is given by Stokes (I9ii8), and described
in detail by Lipson & Steeple (1970).
A computer program was written to evaluate particle sizes from
X-ray line broadening data; details are given in Appendix II.
3-2 Theory of electron microscopy
A detailed account of the theory and practical applications of
electron microscopy and diffraction has been given by Zworykin et al
(19145), Kay (1965) and Hirsch et al (1965).
The wavelength of electron beam is given by:
h J"2meV
where h = Plank's constant
7^ = wavelength
m = electron mass
e = electron charge
V = accelerating voltage
The above equation is subject to a relativistic correction because of
the variation in the mass of the electron v/ith velocity, which in turn
depends on the voltage.
The- wavelength of the beam can be found from the diffraction
67 pattern of a substance with knovm unit cell dimensions and calciilating
a single factor, the camera constant, "A L, where L is the effective
camera length.
Electron microscopy is based essentially on the sana principle
as optical microscopy vrLth the difference that the lens system of the'
latter for the deflection of the beams is replaced by a combination of
magnetic or electric fields having different intensities and directions.
The magnifying power of the electron microscope is considerably enhanced
due to the far shorter wavelength of the electron beam compared with that
of the visible beam. The theoretical limit of resolution, given by half
the wavelength of the radiation used, is 0.022 for the electron micro•
scope and 2OO0S for the optical microscope.
A specimen is studied by transmission microscopy by putting it in the focal plane of the lens system and observing its enlarged image on a phosphor screen or by recording on a photographic film held in a cassette within the instrument. Usually, both facilities are employed,
one to align and select the image, the other to record it. As the high energy electrons collide with gas molecules, they are dispersed and their energy level is considerably lowered. To avoid such collisions
of electrons, the mean free path of the gas molecules is increased by decreasing the working pressure of the electron microscope to about 10
mm Hg. A special lens system is used, by interposing between
objector and projector, to.take diffraction patterns of samples being studied on the electron microscope. Diffraction micrographs are
obtainable only for very thin crystals and aggregates or elements of low mass number, oTrring to the high absorption of electron waves by matter, ©le single crystal diffraction pattern consists of reflections
68 from a plane of reciprocal lattice points, cf,X-rays. The diffraction pattern of a polycrystalline substance in random orientation consists of typical concentric rings.
3.2.1 Apparatus
Diffraction and direct transmission micrographs of powdered materials and transmission micrographs of surface replicas of sintered refractoiy materials for the present work were obtained using a
Philips EM 100 B model electron microscope (Van Dorsten, Nieui-jdorf &
Verhoeff, 1950). It has a reasonably good resolution of 25A. The pumping system of the microscope consists of a prevacuum rotary pump, a merciary diffusion and an oil-diffusion pump. Micrographs of the specimens are taken by means of a camera loaded vdth 35 mm film and fitted in the microscope. The magnification is controlled by varying the currents to the electro-lenses. Various parts of the grid can be observed by means of controls for fociissirig and for moving the sample holder. An image of the sample under observation is thrown on the fluorescent screen directly in front of the observer. In order to take a micrograph of the image on the screen, the camera is loi-zered into position and the shutter opened. The exposure depends upon the illiamination of the image and may be up to several seconds. The magnification is determined by reading a scale and then consulting standard tables, A suitable area of the sample for a diffraction micro• graph is chosen by means of a diffraction selection diaphragm; the diffraction lens is switched on and the intermediate lens switched off.
Longer exposures for diffraction micrographs are required because of their lower intensity. When the electron microscope has started working, samples can be readily changed by removing the grid holder and inserting
69 another one carrying a different sample. This operation tal:es a fraction of a minute. The-usual voltage of electron microscope was ' QOkV,
Carbon and metal films were prepared in a "Speedivac" High Vacuum
Coating Unit 12 E6, manufactured by Edwards High Vacuum Ltd. The main part of the unit is a glass work-chamber, evacuated by an oil diffusion pump backed by a rotary pump. Electric circuits, to strike an arc across carbon electrodes and for the vapour deposition of metal film from a filament, are fitted inside the chamber. Various gauges for readings of pressure inside the chamber and controls for the electricity supply to the circuits inside are fitted on the panel of the instrtiment.
3.2.2 Preparation of samples
Microscopic stiidies of samples were made by scattering the particles on a carbon film supported on a copper grid. The thickness of the carbon film x^as of the order of 2002. The copper grid was of 3.' mm diameter and had a square mesh. The length of the side of square was
100M m. A pair of forceps vjas used to handle the grid throughout the investigation of specimens.
An electric arc was struck betvjeen pure carbon electrodes in the high vacuum coating unit for depositing a carbon film on a mica stirface.
The arc voltage and current vrere lOV and 60A respectively. The arc was struck in about eight bursts, xvith an interval of approximately 3 seconds between successive bursts to cool the electrodes. The'pressure inside the chamber v/as kept below 10"^mm Hg-
* The mica plate was held in a slanting position at an angle of about 30° at the surface of a small trough of xiater and the carbon film floated off on the vjater surface, by gradually lowering the plate below the vjater level xmtil it sank. The carbon film is stripped off the surface of mica by water by virtue of its surface tension. It was
70 facilitated by cutting off the edges of the mica sheet after deposition of the film and contaminating the mica sheet by breathing onto it before deposition. The floating film was deposited on the copper :grid and the residual water absorbed by placing it on a filter paper. The grid so prepared was placed in a vertical cylindrical holder and locked in position I'Tlth a cylindrical cap. The grid was exposed through the open end of the cap. A dispersion of the microcrystalline powder was made in either water or acetone, by keeping it suspended in a liquid tank, vibrating at the extremely high frequency of an ultrosonic unit for about 20 minutes. A drop of the suspension was placed on the copper grid carrying the film and was evaporated to dryness under an infra•
red lamp. Then it was placed in a microscope grid holder, and inserted
in the electron microscope.
3-2.3 The replica technique and shadoi-f casting
The surface features of solids can be studied in minute details
by means of the replica technique. It involves the transfer of a
surface topography of a solid body to a tiiin film which can be examined
by transmission electron microscopy. The surface details may be
sharpened by shadowing with a heavy metal vjhich absorbs electrons
strongly. Carbon replicas with a shadow casting of palladium metal
were prepared as follows.
Polystyrene, grains were melted on a glass slide over a bunsen
biirner. The solid surface of the sintered sample v/as brought into close
contact with the melt and pressed "very gently onto it- It was then
allowed to cool and solidify. This solidified specimen, carrying the
surface impression of the sintered sample, was placed in the vacuum unit
and deposited with a carbon film as described above. It was then
71 3hadcfi-;ed, i,e. coated vjith a film of palladiizm metal as follows.
A thin palladium metal i^ire, placed in a tungsten, filament/-vjas
evaporated by passing through it a heavy current; the metal vxas alloi-red
to deposit on the film replica. The polymer was dissolved away in 1,2-
dichloroethylene. The remaining film was picked up on a copper grid,
dried lander an infra-red lamp and then observed in the electron micro•
scope. Before each evaporation operation, the filament was "flashed",
i.e. its temperature was raised to remove dirt etc. by passing a
slightly higher current through it than was subsequently used for metal-
evaporation .
After completion of a set of exposures, the film was removed from
the electron microscope camera and developed in a fine grain developer
to give optimum contrast. Enlarged prints were made from the "negative"
onto Kodak bromide paper. In this manner magnifications of over 70,000
times the original vrere obtained.
3.3 Scanning electron microscopy
Comprehensive accounts of the theory of SEI-I and its special
applications are given by Thornton (1968). A brief summary of its
featiures is given below.
SEM consists mainly of three types of components:
1. Electron-optical column including electronics
A schematic diagram of the instrument is shown in The column comprises an electron gun and two to four electron lenses. Tlie electron beam passing through the system of lenses is demagnified in diameter to-25o2 or less. The final lens assembly contains two sets of magnetic scanning coils. They are energized by a suitable scan generator to deflect the - 72 Scan E.H.T. generator •o • 2) Chopping coils" Magnification control p. (D o a Lens supplies r7^> Luminescent 2J Scanning coils Emissive Astigmai Specimen bias > Conductive Amplifiers Intensity- 'Linescan' Light modulated displays Vacuum sys Electron- CRT's collector detector beam on the specimen surface in a raster-like pattern- The electron coliunn contains three more items (i) A set of apertures for specifying the angular aperture subtended by the beam at the specimen surface- (ii) An 'astigmat', consisting of a set of coils of special design to overcome any astigmatism in the system, (iii) A set of »chopping' coils or plates for superimposing modulation on the electron beam. 2, Vacuum system, specimen chamber and stage Vacuum is maintained in the electron column and specimen chamber by a pumping system. The specimen stage in the chamber has the facility to move the specimen in the electron beam and examine at a desirable angle to the beam. The inter• action of the electron beam v/ith the specimen gives rise to effects like secondary electron emission, a reflected electron current^ be am-induced conduction and often cathodoluminescence. 3. Signal detection and display system The signals can be deduced and amplified to control the visibility of the bank of cathode-ray tube (CRT). The specification of spot position In CRT and the primary beam on the specimen surface is facilitated by the same scan generator. Usually the signal is fed to the brightness control of a cathode-ray txabe V7ith a long persistance phosphor for visual examination. Signal can fiirther be displayed on a tube with short-persistance phosphor for photographic records. The • synchronism of cathode-ray tubes with primary beam is mani• fested by the scan generator controlling the magnification. Its output is introduced to the deflection coils of the CRT to keep the raster size approximately 10 X 10 cm. The raster 7h • size on specimen is smaller than this. In general terms if the specimen raster is lOM J. WM in one case,-and IXlmm^in another with a certain voltage, then the magnification is XIO^ 2 in the first and XIO in the second case. Additional electronic eqiiipment consists of the high-stability supply for the electron gun, the high-stability current supplies for the magnetic lenses, the control systems for the cathode-ray tubes, the ancillary equipment associated vrLth the varioxis signal detection systems and monitoring systems. For SEM^ samples are simply mounted on the microscope stage and vacuum coated with aluminium to ensure good electrical conductivity and are then placed in the microscope. The Cambridge Stereoscan Si^-lO v/ith a resolution of better than 100 2 was used for study of metal foils (Chapter 6). The instrioment is sitxaated at The Royal Naval Engineering College, Manadon, Plymouth. 3.U Thermoanalytical techniques Of the various analytical techniques knovm as thermometric analysis, two are most commonly in use. First, thermogravimetry (TG) wherein the. weight change of the sample under investigation is followed over given periods of time and the temperature can be varied at any desirable rate. It is specifically useful for studying the reactions of solids involving a change of vreight. The atmosphere of the material under study may be controlled, e.g. an inert or reactive atmosphere may be used. The thermobalance used was a modified version of a double 'pan analytical balance (Gregg & Windsor, 19U5)- In the current research programme, a Stanton Model Ah9 balance x^as used, sensitive up to weight changes of 10~^g. One pan of the balance was furnished, on its underside, with a hook carrying a length of nichrome vnxe. The wire passed through a hole in the balance shelf and supported a silica sample bucket, which was suspended in an electric furnace controlled by a Stanton-Redcroft linear programmer. The measurement of temperature in the vicinity of the sanxple was made by means of a chromelalumel thermocouple placed close to the sample bucket and attached to a milli-voltmeter (Baird & Tatlock-Resilia)- Va27ying amounts of samples, 0.5 - 2-5 g^ vjere weighed accurately into an aluminium crucible (Thermal Syndicate Thermel Alumina). The vjeight change in the samples vj-ere folloT^ed at known intervals of time. In the present x-jork, kinetic and heat treatment studies were carried out with air as the reacting medium. The kinetic behaviour of the various reactions was followed by regression analysis (least square fit) over given periods of time. The second commonly used method for thermometric analysis is differential thermal analysis (DTA), first developed by Houldsworth & Cobb (1922). The test and inert materials had embedded in them separate thermocouples vjhich were connected at their opposite ends. This arrange• ment enables the measurement of emf produced during the transfer of heat during the reaction process, and temperatures at which such changes take place. Throughout the present research v/ork, apparatus based on the design described by Grimshaw, Heaton & Roberts (l9hS) was used. 0.5 - 1.5 g of the samples vjere placed alongside the reference material, recrystallized alumina in a ceramic block. This was heated in an electric furnace (Griffin and George) at a linearly-controlled rate of 10 to 20°/min. by means of a linear programmer (Stan^'on-Redcroft). An automatic recorder indicated the temperature of the block as well as the heat change over the temperature range of 250° to lOOO^C, in order to determine the temperature required for the onset of the reaction. 3-5 Surface, area measurement by gas sorption This method of surface area measurement depends on the fact that tb** 76 quantity of a gas adsorbed on the surface of a material-is a^function of the specific surface, i.e. the surface area per unit mass. From the specific surface, the average crystallite size may be estimated for powders having crystallites of approximately uniform shape and simple geometry. Glasson (1956 and 1958) and Gregg & Sing (1967) have given detailed descriptions of the method. To obtain the monolayer capacity, x^, from the adsorption isottierm, the most commonly used method is that given by Brxinauer, Emmett and Teller (1938). According to the B.E.T. equation:- P = c - 1 . _2_ + _1_ (i) x(p° - p) x^c p° x^c where: p = pressure of adsorbate vapour in equilibrium with absorbent. p^ = saturated vapour pressure of vapoiu? adsorbed. X = amount of vapour adsorbed, x^ = capacity of filled monolayer, c = constant- There are five main types of the adsorption isotherms as classified by Br\mauer, Demming, Demming & Teller {19hO) (commonly referred to as the B.E.T. classification). Types II and IV are in good agreement vjith the B.E.T- equation for determing the specific surface-of substances, while type IV is applicable for the determination of the pore size distribution, Hovrever, type II gives best agreement with the B.E.T. equation over limited ranges of relative vapour pressure (Gregg, 1961). A plot of p VS _g_ gives a straight line with c - 1 as slope and x(p° - p) p° x^c 1 as intercept. Values of c and x^ can be calculated from these two ^m^ 77 parameters. The linearity of the relationship between p/x(p^ - p) and p/p° applies only between values of p/p° from 0.05 to about 0.3. The amount of gas adsorbed can be determined either gravimetrically or volumetrically (Gregg & Sing, 196? p.310). The specific surface, S, varies vxith x^ according to the relation- ship S = x^ N. A m. m M where: M = molecular v/eight of adsorbate. N = Avogadro's number. A = Cross-sectional area of an adsorbate molecule in a m completed monolayer. From the specific surface (s) of a powder, the average crystallite size, 1, assuming that all the particles are spherical, can be determined easily. P= density of the solid (adsorbent). This relationship is applicable for particles of cubic shape also . Expressions for the other" shapes, (e.g. plate- and needle-shaped part• icles) can be derived easily. 3«5«1 The apparatus The sorption balance developed by Gregg (19ii6, 1955) has been used throughout in the present work. The glass beam of thp sorption balance is supported on saphire needles, which are put into a glass cradle. One arm' of the balance carries a bucket for the sample with counter-weights, and the other carries a solenoid or magnet enclosed in a glass envelope surrounded by an external solenoid. The whole balance is enclosed in a 78 glass case and other accessories like vacuum pumps, gauges, and gas reservoirs are connected to it. The glass case can be evacuated and filled \n,ih any desirable gas. Descriptions of the sorption balance and the low temperature nitrogen sorption method are given by Gregg (I9ii6) and Glasson (1956). The technique is now an established one for the determination of particle size (BSii359, part I 1969). 3.5.2 Measurement of sorption isotherms The samples for specific surface stxidies were outgassed in the specimen bucket to remove adsorbed vapours and moisture on their sxirfaces, The temperature of the specimen v/as maintained at 200° by surrounding the glass limb with furnace during this operation (Glasson, 196ii). Nitrogen is maintained by boiling liquid oxygen coolant contained in a Dewar flask The initial x^eight of samples was determined in vacuo, follovjd by additions ("dosing") of nitrogen into the apparatus. Observations of sample v/eight versus corresponding nitrogen gas pressures v/ere taken under conditions of eqioilibrium. To determine the desorption section of the isotherms, sample weights were recorded at decreasing equilibriiim nitrogen pressures, when instalments of nitrogen were pumped out of the balance. The weight corrections for buoyancy effects of the sample and container had to be applied to all weight changes. Such corrections were determined from experiments carried out under the same conditions with sairples of known X-ray density and negligible surface area. The quarter-milligramme sensitivity of the vacuum balance gave an acciiracy 2 1 of + 0-1 m g" on 10 g samples, leading to possible errors of over 3% 2 1 where the specific surface, S, technique are basically similar to those described in the original paper 79 involving use of a vacuum balance for low-ten5)3rature surface area determination (Glasson, 1956). Thus, the liquid oxygen bath remained constant within + 0.2° and at least Ih vjas allowed for the sample to attain a constant temperature. In practice, the sample is generally up to about 1° warmer than the liquid oxygen outside the balance limb (as indicated by internal and external thermocouples). The sample shows a temperature constancy similar to that of the bath(+ 0.2°), and dependent to some extent on the sizes of the sample containers and hangdown tubes (up to 30 mm diameter), depth of immersion in the liquid oxygen (over 15 cm) and possibly on the surroiinding nitrogen gas pressure. By standardising the equipment and improving the heat insulation at the top of the Dewar flask, the sample temperature was kept vjithin + 0.1°, thereby minimising the variation in the s.v.p. of the nitrogen to preserve an acciiracy of better than 3% in the surface area determination. The oxygen isotherms, v/hich extended to a relative pressure, p/p°, near unity, • exhibited little or no hysteresis at p/p°^ 0.3- From these and the nitrogen isotherms, S could be calculated by the B.E.T. procedure, using values of lU.l 2 ' and 17.0 for the cross-sectional areas, A , of oxygen and of nitrogen respectively; this gave agreement v/ithin ca * S% in the values of S obtained from both series of isotherms. The older graphical and nevjer computer (with line-plotter) methods"(b*Weill, 1969) agreed within + 1% for values of S from each individual isotherm (Glasson & Linstead-Smith, 1972). 3.6 Sintering of materials The sintering of boron carbide with and without different additives was carried out in argon as vrell as in vacuum. 80 Initially a high temperatvire furnace P.C.IO (Metals Research, Cambridge) was \ised for sintering finely-divided boron carbide with metal'additives. After some cycles of heating for the sintering of boron carbide with aluminium up to 1,800°C, the inner tube of the furnace failed. Investigation into the cause of failure led to the following explanation. Aluminium, being volatile at such high temper• atures (m.p. 6$9'7^C b.p. 2,057*^C), evaporates and reacts with the aliimina of the tube to give AlO. The latter is a much more volatile oxide and its formation and evaporation mechanically weakens the tube at high temperattires. After replacement of the tube and element in the P.C.IO furnace, a second start was made with iron as the additive to boron carbide. The furnace again failed, this time due to a technical fault in the manufacture of the element- A third start was made with iron as additive, but this was followed by a tube failure which led to complete closure'of this-furnace and never was it used again in this work. Investigation by Metals Research engineers suggested the incompat• ibility of boron carbide with alumina. Hovjever, boron carbide was heated with recrystallised alumina from crucibles at 2,000°C later in this work, but X-ray analysis shoxved no reaction between the components. This alumina was found to be in o( - and - forms, v/hich may account for its mechanical instability towards thermal shock. 3.6.1 Construction of High Temperature Furnace After these- mishaps, a vacuum furnace vjas constructed. Fig. 3-2. being pox-jered by a four kilwatt radiofrequency induction heater (Delap- ena E U kV/) with the wound coil external to a 1 in. diameter alumina tube. The tube was evacuated by a single stage rotary pump (Edwards Speedivac IS 150) backing a two stage oil diffusion pump'(Edwards Speedivac li03A), Vacua of between 10"^ to 10"^ mm Eg were achieved. 81 Fig. 3.2 High temperature vacuum furnace of sintering studies Optical pyrometer Silica sheath Crucible R.F. coil Vacuum gauge Diffusion pump Rotary vacuum pump Optional Gas inlet 82 After several failures, the alumina tubes were replaced by fused silica tubes (Thermal Syndicate) having better thermal shock resistance. Hoi-rever, the silica txibes can only be heated to betvxeen 1,000° and 1,1|00°C and for limited times to avoid extensive recrystallisation and cracking when cooled. Contact had to be avoided betvreen the silica tubes and the graphite crucibles for the induction heater. In order to work at temperatures between 1,000° and 2,000°C, alumina tubes were reintroduced in a modified form. Tv/o tubes were placed end to end in the hottest part of the induction-furnace, as shovm in Fig. 3.2. .This arrangement minimised mechanical strain caused by thermal shock, yet offered thermal resistance to heat rad• iated towards the x-jalls of the outer tube. The inner tubes were kept vertical by attaching their far ends to asbestos sheets, the top sheet also closing the end of the outer tube. The crucible was supported on an alumina pedestal standing on the bottom of "tJie outer tube. The height of the pedestal was approximately that of the length of the lovrer inner tube so that the crucible rested near the jiuiction of the tx^o inner tubes, surrounded by the copper coil for R.F. induction heating. The upper parts of the apparatus were sealed with Kos aluminous cement covered also by rubber seals to ensure air-tightness. Porosity'to argon was eliminated by coating the cement and asbestos with a uniform thick layer of aluminium paint. The reading of temperature by a disappearing filament optical pyrometer (Foster) x^as facilitated by having a glass window fastened by a rubber seal to ihe upper end of the inner tube. IJie main featiores of this furnace are:-' (a) Its design enables it to be resistant to thermal shock, poss• ibly tolerating lower grades of oC-Al20^.for the tubes. Samples 83 can be heated up to 1,800°C in 5 minutes and cooled back to, working temperatiire in 15 minutes; cf.the P-C-10 furnace which requires three hours for similar heating cycles. (b) The sample can be seen through a glass window at a distance of 6 ins. from it, and photographic methods could be used to follow the course of reactions. • (c) It is more economic to run and does not need a flow of 90^ nitrogen-10^ hydrogen, as required by the Molybdenum vjindings of the P.C.IO furnace- (d) It can be modified for sintering vjork at higher temperatures, up to 2,500*^C using magnesia thoria tubes 3.7 Reaction sintering of boron carbide with metals by hot pressing Three hot pressing facilities were used for this work. 3.7-1 Laboratory hot-pressing system i A small seals laboratory hot-pressing system (Fig. 3*3) was set up to investiage the pressure sintering, properties of small quantities (lOg) of pox-Kiers. The system is based upon a double-acting mechanical press, designed by Roeder and Scholz (1965), capable of working at temperatures up to 3,200°C and pressures up to 1,000 kg cm"^. The resistance-heated graphite die set is held between water-cooled copper electrodes, the power being supplied by a 60 MftT single phase transformer v^ich can deliver up to 3,000 A at 2OV5 the original design employed a smaller (2U,HV) transformer. Since the electrical resistance of-the die is inversely proportional to its cross-sectional area, the higher power available from the larger transformer vrLll enable different die ( and hence sanqile) geometries to be investigated. The povrer supplied to the transformer is regulated by means of a 8U Fig. 3.3 Laboratory hot pressing system Piston J^l Cooling water Piston UUUUU Transformer rrrrrinrnn Isolator itltO-V si-jitc^i Input I I I 5 Potentiometer T = Thyristor F = Firing.circuit V = Transient voltage protectors 85 thyristor control system designed Biddxilph (1972) and further developed during the present work. The basic circuit consists of two thyristors connected in inverse parallel, mounted on a water-cooled copper busl:^ is regulated by a firing circ^lit. The firing circuit incorporates a potentiometer, the adjustment of which provides a direct control of the pox^er supply. Thyristor control of resistance heating is preferred to the conventional saturation reactor type since a more precise regiilation of the sample temperatures can be achieved. 3.7-2 Industrial hot-pressing systems Samples of borides and carbides were hot-pressed at Bullock Diamond Products Laboratories, Torpoint, using a graphite mould set betvxeen hydraulic rams and heated to temperatures lower than the melting point of the respective samples, by a 36 kt/ R.F. induction heater (V/ild- Barfield), Fig. 3.U. The heat.of the die set was contained by carbon black powder (charcoal). The temperature and"pressure were increased continuously (up to approxijnately 100 - l50°C below the m.p. of the sample) until the ti-ro rams had moved closer to each other by a pre- calculated distance. This calculation v/as based on the theoretical dens• ities. Hot-pressed samples of up to 80^ theoretical density were prepared. A disappearing filament pyrometer (Foster Instrument) v/as used for temperatxire measurement-* After completion of hot pressing'the v;hole assembly was allowed to- cool, before being dismantled to remove the samples. These were tested for chemical composition, phase-compos• ition and mechanical properties. Samples of CaB^ were hot pressed at Borax Consolidated Research Centre (Chessington). Rams 35-5 - I4O.6 cm long and 2.5U cm in diameter were used to press the specimens in a spiral die. The progress of densification vras folloi-red by noting the moverrent of a plunger as the 86 Fig. 3.U Hotpressing set up for compaction of boron carbide H 0 (////. ///^ B f//^ ///////, ////// ////// n H Hydraulic ram R = R,F. coil G = Pressure gauge A = Asbestos shield I = Ram-travel indicator D = Graphitedie C = Carbon black P = Optical pyrometer B = Boron carbide S = Slighting tube 87 temperature and pressure were raised- 3.8 Hardness testing of coatings 3.8.1 Mounting of sample Hardness tests were performed on the siirfaces of metal foils reacted with boron carbide at temperatures 1,000^C - 1,800°C. Some of the specimens were mounted on synthetic resin in the sample mounting machine. The sample was placed at the centre of the bottom of mould and covered vrith approximately 30 cm"^ of Bakelite. Heating was sid-tched on to cure the Bakelite and pressure vzas exerted on it slowly and 6 -2 steadily up to 1.37 x 10 to" until it retained shape for a few minutes. 6 -2 The pressure was then raised to 2.75 x 10 Nm~ and kept constant for five minutes* The heater was sx^itched off, the sample cooled by a flow of water for five minutes and then taken out of the mould. Alternatively some samples x^re mounted on cold setting resin. Cold setting resin, 'metset resin >SW» > (Metalliirgical Services Ltd.) was mixed vjith 'metset hardner' in the ratio of 1 drop of hardner to 5 cm^ of resin in a plastic container and stirred to ensure' homogeneity. The samples vxere placed at the centre of the moiilds and filled with this setting mixture. They T^re left overnight for setting on-an even surface and taken out from the motilds the follovring morning. 3.8.2 Polishing Mounted specimens vrere polished by.grinding on different grades of silicon carbide paper, fixed on smooth doxraward slanting glass plates. A continuous flow of water was spread evenly on the • paper to ensure wetting during the grinding. Saii5>les vjere ground on varying grades of rough and smooth papers in the order "Roughes minor" No. 220, No. 320, No. hOO and finally No. 6OO (Strues Scientific Instruments). Alternatively some specimens were polished on an automatic or a hand polishing machine. The specimens, after polishing, were washed, 88 dried and tested on a Hardness Tester. 3.8.3 Projection microscope and microhardness testing eqiiipment • Detailed description of the equipment is given by Troughton & Simms (1956). A brief account of its important features is given belovj. The assembly consists of a projection microscope and is designed for microscopic examinations and photography of: 1- Opaque objects using (a) normal incident illximination with a plain glass reflector; (b) incident illumination with a metallic reflection; (c) dark field illiimination; (d) polar• ized light; (e) phase-contrast; and (f) normal incident and oblique illumination. 2. Translucent objects using (a) transmitted light; (b) polar• ized light; (c) phase-contrast; and (d) transmitted light Other facilities include Micro Hardness Tester, equipment for surface topography and ultra-violet light. Present work involves study of opaque surfaces and their hardness values. A brief description of Micro Haidneas Tester is given below. 3.8.3*1 Micro Hardness Tester A Vickers pyramid diamond whose faces have been vjorked to an angle of 136*^ is embedded in the outer optical surface of iiie microscope objective, thus the area to'be tested coiild be selected and the .indent made and evaluated without the interchange and exact registration of indenter and objective. The load may vary from 0.1 to 500 g depending on the specimen hardness. A load of 20 g was used throughout the present work. The specimen was secured to one end of an acciirately balanced lever and weight was applied to platform above the specimen. The combined objective and diamond indenter were advanced toi-zards the speci- 89 men by means of the slow motion focussing adjustment of the microscope and contact was indicated by the signal lamp. The measurement of the impression was made vrith the aid. of the Filar Eyepiece. Microhardness was read directly from standard tables. 3.9 Computer programming Computer programs v/ere x-jritten for various calculations carried out in the course of this work. One of these has been discussed already in connection vjith X-ray line broadening (Section 3.1»U and Appendix II). Thermodyr^amic parameters, i.e. free energy change, heat of reaction and eqiiilibrium constants for various methods of production of borides have been computed from the equations given by Schick (1965). Thermo• dynamic functions for reactions where the constants are not known, have been calculated from table values. A program for computing free energy change, heat of reaction and equilibrium constant at various temperatures is given in Appendix II, together with specimen output for the reaction: TiOg •+ 2B + 2C = TiB2 + 2C0 The computed values have been plotted as Ellingham diagrams using a graph plotter and a modified version of an existing program. This modified program is given in the Appendix. Fractional volume changes (Chapters 5 and 6) for conversion of metal to boride (and carbide) and then.to oxide have been computedLJfor all known borides and carbides. The program is given in Appendix XV, together with an output sample. Complete outputs and programs written for calculations during this work are available in a separate folder from Plymouth Polytechnic Library. 90 PART II T H E S I "S Chapter h Reactivity and sintering of boron carbide with metal powder additives Chapter $ Effect of additives on the hot pressing of boron carbide Chapter 6 The formation and microstructure of boride and carbide coatings on metal surfaces Chapter 7 Oxidation of boron carbide Chapter 8 Concluding summary 91 CHAPTER IV REACTIVITY AND SINTEKENG OF BORON CARBIDE WITH METAL POVJDER ADDITIVES ii.l Introduction Previous researchers (Jones, 1970) have described the production of boron carbide and shoi-7ed how the sintering was accelerated by chromium metal powder additive (Glasson Sc Jones, 1969)- The sintering was accelerated markedly only at higher temperatxire, ca. 1800?:. The metal completely wetted the boron carbide surface (Hamijan £c Lidman, 1952), Some graphitisation of carbon was noted at this temperature; this could have left some boron in solid solution with the remaining - boron carbide or chromium, but no zone of interaction producing crystal• line chromium boride or carbide was found. This behaviour of chromi\am contrasts with that of iron which forms zones of interaction when it accelerates the sintering of boron carbide. Other transition metals, e.g. Co and Ni, give similar zones, apparently consisting of boride and carbide alloys of the corresponding metals. In the present research the effects of iron and several other metal powders on the sintering of the boron carbide are examined and compared with one another. Possible compoxind formation-during the sintering processes is investigated at a series of temperatures between 1000° and 1800°C. U.2 Experimental li.2.1 Materials 2 -1 The boron carbide used had a specific surface of 20.6 m g* corresponding to an average crystallite size (eqiiivalent spherical 92 diameter) of 0.106// m. Portions of the material were mixsid with knoxm amounts of pov/dered metal additives of size generally l-M'm; occasionally metal hydride powders, e.g. titanium and zirconium^vxere used as additives. U.2.2 Procedure The samples v/ere calcined for fixed times usually 5 hours in vacuo at lOOO^C and argon at 1000°, 1200°, HiOO^, 1600° and 1800°C. The specific surfaces of the cooled samples vjere determined by the B.E.T. method (Brunauer, EmmettS: Teller.' , 1938) from nitrogen sorption isotherms recorded at -iSJc on an electrical sorption balance (Glasson, 1956 and 196U). The fiimounts of metal additive were normally 1% and 10^ by weight of boron carbide. Although these amounts often accelerated sintering considerably, they were insufficient to give complete X-ray patterns of any metal borides or carbides formed. Thus, it was necessary to compare separately heated mixtiires, containing larger amounts of metal additive, generally in stoichiometric amounts required for complete metal boride and/or metal carbide formation. These experiments were carried out and, the results are diicussed below. ii.2.3 Results The variations in specific surfaces of the sintered boron' carbide samples are shown in Figs, ii.l - ii.9, where they are compared with' the average crystallite sizes (equivalent spherical diamters) calciilated from the specific surfaces and the X-ray densities of the products. Tables U-1 - U.9 show the main metal boride and carbide phases formed at different temperatures. Decreases in the number of crystallites during the 5 hour sinterings 93 of boron carbide with different metal additives at 1800*^C in argon are compared in Table U.IO. The multiple changes are calculated from the ratio (S-^/S)"^ where S-j^ = specific surface of the initial boron carbide (or from the average crystallite size ratio), with allowances being made for up to 10^ of metal of comparatively low speicific sxirface and nximber of crystallites being present initially and for change in density during any chemical reaction between metal and boron carbide. Further information on the microstructure of the sintered samples is provided by electron-micrographs (Plates 3.1 - 3.22) which show the merging and rounding of the aggregates of crystallites as sintering proceeds at various temperatures (5 hour calcinations) in the presence of different metals. This is discussed in Section ii.li. U.3 Discussion As demonstrated earlier (Glasson & Jones, 1970; Jones, 1970), sintering of the boron carbide is enhanced by high temperatxires and times of heating. Metal additives are expected to accelerate the sintering . generally, by analogy with the previous findings for chromium. The effect of each additive v/ill depend on its ability to form solid solutions or . compoiuids with the boron carbide. The consequent changes in surface properties affect sintering by surface diffusion or crystal lattice diffusion according to temperature conditions. i;.3.1 Iron additive The extent to irtiich iron additives (1% or 10%) accelerate sintering of "boron carbide at different temperatures is illustrated in Fig. U.l- For more complete comparison, the broken-lined cujrve in Fig. ii.la represents the corresponding surface areas for Ig boron carbide samples containing the 10% metal additive of negligible surface area (less than 9U TABLE ii.lO MULTIPLE CHANGES IN THE NUHBER OF CRYSTALLITES DURING 5 .HR. SINTERINGS OF BORON CARBIDS VJITH METAL ADDITIVES AT iTSOO'^C IN ARGON Fractional change in- No. of initial Boron total no. of Crystallites Carbide Crystallites per Additive (10-2) Crystallite of sintered products 0% 1% 10% 0% 1% 10^ Fe 9.2 0.38. 0.039 10.9 263 2,550 Ti 9.2 6.0 h.S 10.9 16.7 22.2 ^ Zr 9.2 h.2 2.6 10.9 23.8 38.1 V 9.2 6.3 ii.8 10.9 15.9 20.9 Nb 9.2 9.0 7.7 10.9 11.1 12.9 Ta 9.2 6.6 3.6 10.9 15.2 28.0 Mo 9.2 ' 7.0 5.8 10.9 Hi.3 17.3 V/ 9.2 9.7 5.8 10.9 10.3 17.3 Al 9.2 . 8.6 7.6 10.9 11.6 13.2 95 1000 c B, C only • o P >0D 10% Fe 1.6W m, 10% tfe 6 «m 1800°C 101 Fe I 1 ,800°C 1600 C M H H H H Boron carbide oo ON P- rj o only 8 8 88 8, o o o o o S-1000"C o o o o o 1200 0.1 m2 ), i.e. the specific siirfaces that the sample would have had if the iron had not reacted with the boron carbide or accelerated (or retarded) sintering. The position of this broken-lined curve at 1000°C (point A) coincides with that found experimentally, showing that 10% iron has little or no effect on the sintering of boron carbide at this temperature, but considerably accelerates sintering at higher temper• atures. Tnis is illustrated also by the curves in Fig- U.l, which further shows that the effect of the iron usually diminishes consider• ably after the first 1% has been added. The iron has correspondingly less effect on the sintering at 1600°C than it has at lli00°C, cf. Fig.U.la, EC and B»G». This is ascribed to some activation Tirtien the iron reacts more extensively vrith the boron carbide at 1600°C. Thus, there is more activation xri-th 10% Fe than there is with 1% Fe additive (specific surface changes between lli00° and 1600°C are from h.9 to 7-2 (BC) and 8.0 to 8.6 ra^g"-*". (B»C') respectively). The above findings are in accord with phase composition identific• ation by X-ray analysis of' the sintered mixtures and separate mixtures containing large amounts of stoichiometric metal additives for metal boride and/or carbide formation at similar temperatures. As shown in Table ii.l, there was little or no reaction at 1000°c and only small amounts of iron boride FeB were formed at 1200°C. Most of the 10% iron additi^/e was converted to FeB in 5 hours at lli00°C and larger amounts of iron, viz. hFe and llFe per B^C, gave FeB and also some Fe^C where sufficient iron was present. Formation of both borides FeB and Fe2B and carbide Fe^C were much more extensive at 1600°C^while at 1800°C the products were entirely Fe^B and Fe^C indicating complete 97 TABLE U.l COl^OSITION OF THE SYSTEM B^C - Fe AT DIFFERENf^CAIX^INATIOfTfEMRSRATURES Temgerature Additive Products 1 000 10^ Fe No appreciable reaction l;Fe/B^C Small amounts of FeB 1 200 10^ Fe No appreciable i*eaction UFe/B^C Traces of FeB llFe/B^C Traces of FeB 1 UOO 10% Fe FeB, B^C liFe/B^C FeB, Fe, B^^C llFe/B^C Fe^C, Fe 1 600 10? Fe FeB, B^C UFe/B^C FeB, Fe^B, Fe^C llFe/B^C Fe^C 1 800 10% Fe Fe^B, Fe^C, phase X id.th peaks d^ = 2.1|8, d^ = 2.71 A. llFe/B^C Fe B, Fe C 98 reaction: B^C + llFe '. ^ UFe2B + Fe^C Tne activation opposing the sintering at 1600*^C, therefore occurs when the temperature is high enough for. both boride and carbide form• ation to be extensive. This causes maximum changes in molecular volume of the crystal lattice of reactants and products, leading to more extensive strain and crystallite splitting/ as often encountered in solid-state thermal reactions. The products are more extensively sintered at higher temperatures (l800^C) , assisted particularly by the comparatively lo^^-melting Fe^B (m.p. 1390*^C), cf. Fig.U.l, CD and CD'. U.3.2 Titanium and Zirconium additives The sintering of boron carbide is accelerated by titanium and zirconium additives at all temperatures between 1000° and 1800°C as shown in Figs.U.2 and ii.3> as found for iron, the effects of the additives diminj.sh considerably after the first 1^ present. The surface areas with the 10^ additives at 1200°C are slightly higher than expected; this is ascribed to activation caused by crystallite splitting when all of the additive is completely converted to TiB^ or ZrB^, compared with only partial conversion within 5 hours atlOOO^^C. Ihis formation of TiB^ is analogous to its production by the reaction: B^C + 2TiC = 2TiB2.+ 3C also occuring extensively at 1,200*^C (Nelson, V/illmore & Womeldorph, 1951). There may be some carbon formed in the reactions: 2Ti + B^C = TiB2 + C and 2Zr + B^C =' 2ZrB2 + C, and released form solid solution in the boride-carbide matrix, contributing to the higher surface area. The carbon forms TiC when larger amounts of titanium and zirconium are present in stoichiometric ratios of 2Ti/B|^C or 3Ti/B^C,• cf. Tables U.2 and ii.3. 99 b. Boron carbide + inert additive ^5! 1 OOOOC 1.000°C ^ ^ S00°C AO^UOO c H 1% Ti s^.-eoo'^c 10% Ti 1.800^0 I 1 600 c 10% Ti oron carbide only H •-3 o H 1 000 1 200 1 UOO . 1 600 1 800 i Boron carbide + inert additive OOO^C Boron carbide 200^C CO only A-1 Uoo°c ^ 600-C 1% Zr ^ eoo^c 10% Zr o i R 10% Zr 1 800*^C 1% Zr tM M 1 600°C O 1 Uoo'c Boron carbide 4 200°C only l.OOO^C •-3 H VA o H 1 000 1 200 1 UOO ' 1 600 1 800 0 1 10 1 TABLE ll.2 COI^POSITION OF THE SYSTEM Bj^C - Ti AT DIFFERENT CALCINATION TOSPEEIATURES Temperatiire Additive Product 1 000 10? TiH^ TiB^, B^C 2TiH2/B^C TiB^, TiC 3TiH2/B^C TiB^, Tie 1 200 10? TiH2 TiB2, B^C 2TiH2/Bj^C TiB2, TiB, TiC 3TiH2/B^C TiB2, TiB, TiC 1 hoo 10? TiH2 TiBg, B^C 2TiH2/B^C TiB2, TiC TiB2, TiG 1 600 10% TiHg TiB2, B^C • 2TiH2/B^C TiB2, TiC 3Tifl2/B^C TiB2, TiC 1 800 10? TiH^ TiB2,B^C TiB2, TiC 3TiB2/B|^C TiB2, TiC 102 TABLE I1.3 COMPOSITION OF THE SYSTEM B^C - Zr AT DIFFERENT CALCINATION TEMPERATURES Temperature Additive Product « 1 000 10% ZrH^ ZrB^, B^C ZrB2, ZrC ZrB^, ZrC • 1 200 10% ZrHg ZrB^, B^C 2ZrH2/B^C ZrB^, ZrC 3ZrH2/B^C ZrB^, ZrC 1 hoo 10? ZrH2 ZrB^, B^C ZrBg, ZrC ZrB^, ZrC 1 600 10% ZrH2 ZrB2, B^C • 2ZrH2/B^C ZrB2, ZrC 3ZTn^B^C ZrB^, ZrC 1 800 . 10% ZrHg ZrB^, B^C 2Zrl{^B^C ZrB^, ZrC 3Zvn^B^C ZrB2, ZrC 103 Titanium and zirconium additives are correspondingly less effective than iron additive in promoting sintering of boron carbide mainly because of the higher melting points of TiBg (2980°C) and ZrB^ (30U0°C) compared xd.th Fe^B (1390°C) and FeB(l5iiO°(^.- Hence, although titanium and zirconium borides can promote sintering by sxirface diffusion above about 900°C (corresponding to about § m.p. in K), they can supplement this by crystal lattice diffusion only above about lUOO°C (corresponding to about J m.p. in K, i.e. the Tammann temperature) (Glasson, 1967). Ihe carbides formed at the higher temperatures, viz. above 1600°C, behave similarly ( m.p. TiC 3l50°C, ZrC 3530°C, Fe^C 1650°C), so that titanium and zirconium carbides can promote sintering by crystal lattice diffusion only above about lli50°C and 1650°C. ii.3-3 Vanadium, niobium and tantalum additives All of.'these additives enhance the sintering of boron carbide to varying extents dependent on the melting points of the metal borides and carbides formed and the extent to which the surface activation accompanying the metal boride and carbide formation offsets the loss of. surface caused by sintering, cf. Figs.ii.ii, U-5 and li.6. The vanadium additives are the most effective for enhancing sintering especially at lliOO^C Up to this temperature, the vanadium shovjs a-greater tendency to form borides VBg (and V^B^ iwhen more vanadium is present) than to form its carbide VC, cf. Table li.U. At higher temperat'iu?es, larger amounts of carbide are formed which may account for surface activation at 1600^0. Niobiiim and tantaliim additives are comparatively less effective, but their general behaviour with change of temperature; resembles that of vanadium, cf. shapes of curves in Fig. i;.5a and c ; they also tend to form borides rather than carbides at temperatures lOli . Boron carbide inert additive Boron carbide only 1% V 10$ V 1 liOO^C O.S6/im 10% 1 300° C 1 600"C Boron carbide 1 200^ C only 1 000°C 1 000 ' 1 200 'l UOO 1 600 Boron carbide + inert additive 1 OOO^C Boron carbide ^^U00°c 1^ Nb only A-1 600°C 10% Nb ^-^iOO^C 10« Nb 1 800°c i^Nb i Uoo°c Boron carbide 600°C 2002c only 000°c 1 000 1 200 " i.Loo ' 1 600 ' 1 boo 10 1000°C Boron carbide 1200°C only 10% Ta d. 10^ Ta 1800°C 1% Ta Boron carbide e-1200 only LDOa C to- 1000 1200 ihOO •"TSoo ^ % Tantalum additive TABIE h.U COMPOSITION OF THE SYSTEM B^C - V AT DIFFERENT CALCINATION TEMPERATURES Tempsrature Additive Products °C 1000 10? V VB2, B^C 2V/B^C VB2, phase X with peaks d^ = 2.0336, d2 = 2.06, d^ = 2.08, d^ = 2.195, dg = 2.386, d^ = 2.U6 • 1200 10? V VBg, B^C 2V/B^C VB2, VC 5V/B^C V^B^, VC liiOO 10? V VB2, B^C 2V/B^C .VB2, V^Bj^, VC 5V/B^C 1600 10? v" VB2, B^C 2V/B|^C VB2, V3B^, VC 5V/B^C VC 1800 10? V VB2, B^C 2V/B^C VBg, VC . 5V/B^C V^B^, V3B2, VC 108 below lliOO^^C,. cf. Tables U.5 and li.6- The above findings are in accordance with the melting points of the vanadium borides, VB2 and V^B^ (2U00° and 2350°C) and carbide VC (28lO°C) being correspond• ingly lower than those of the niobium and tantalum borides and carbides, NbB2 . OOOO^'c), TaB2 (310p°C), NbC (3U80°C), TaC (3880^^0. Also,the fractional volume increases when the metals are converted to these borides and carbides are greater for vanadium than for niobiiam and tantalum: VB2 (0.713), NbB2 (0.5l6), TaB2 (0.h8l), VC (0.317). h'3-h Molybdenum and tungsten additives Both metal additives generally promote sintering of boron carbide, the extent depending on the melting points of the metal borides and carbides formed and how far surface activation accompanying the metal boride and carbide formation offsets loss of surface caused by sintering, cf. Figs, h'7 and i|.8. 10% molybdenum and tungsten additives enhance sintering at 1200°C, 1? Mo is almost as effective. At this temperature, the additives form mainly borides, Mo2B^ and ^28^; larger amounts of metal, viz. 2Mo or 2W per B^^C or 8M0 and 6\r^/B^Cf give lower borides, M0B2, 6' MoB, ft' MoB, ^f- M02B, V/B2, WB, Y - V/gB v/ith only a trace of a lox^er molybdenum carbide M02C and no detectable tiuigsten carbides. In the sintering experiments the 10% molybdenum additive gives, appreciable amounts of M0B2 as well as M02BJ at 1600*^ and 1800*^C, which may account for the activation at 1600*^C. With larger amoTints of metals, the X-ray diffraction traces show that molybdenum and tungsten only begin to form carbides to ar^r appreciable extent at temperatures above 1600°C, cf. Tables U-7 and 1;.8; this accounts for some surface activation of the boron carbide by the tungsten additive even at 1800*^C (Fig. U.8a). The melting points of the borides and carbides are' 109 TABIE h.^ COMPOSITION OF THE SYSTEM B^C - Nb AT DIFFERENT CALCINATION TE-IPERATURES Temperatures Additive Product 1000 10% Nb NbB2, B^^C 2Nb/B^C NbB2, NbC 5Nb/B^C NbB^, NbC 1200 10$ Nb NbB2, B^C 2Nb/B^C NbB^, NbC liiOO 10% Nb NbB2, B^C 2Nb/B^C NbB2, NbC ^ 1600 10$ Nb NbBgi NbC, B^C 2Nb/B^C NbB^, NbC 5Nb/B^C NbB2, NbC 1800 10$ Nb NbB2, Bj^C 2Nb/B2^C NbB2, NbC 5Nb/B^C NbB2, NbC 110 TABLE U.6 COIPOSITION OF THE SYSTEM B^C - Ta AT DIFFERENT CALCINATION TEMPERATURES Temperature Additive Products 1000 10? Ta TaB2, B^C 2Ta/B^C TaB2, TaC 1200 10? Ta TaB2, B^C 2Ta/B2^C TaB2, TaC 5Ta/B^C TaB2, ^- TaB, TaC ll;00 10? Ta TaBg, B^C 2Ta/B2^C TaB2, TaC 5Ta/B^C TaB2, TaC 1600 10? Ta TaBg, TaC, B^C 2Ta/B^C TaB2, TaC 5Ta/B^C TaB2, TaC 1800 10? Ta TaB2, B^C 10? Ta + Al2b3 TaB2, TaC, ^and Y- AI2O3 2Ta/B^C TaB2, TaC 5Ta/B^C TaB2, ^- TaB, TaC 111 2 -1 mi Hi : HT i000"C Boron carbide ^ 1600^0 only 1% Mo 10^ Mo • OO^C d. o.U A m 1800°C 0.3 10^ Mo •1200°C 1^ Mo •lliOO°C Boron carbide ^1600° C only' ^1000° C 0.2 p lo 0.1 i 10 1000 1200 moo i5oo Tiffoo J rt. b. m _ carbide + inert additive °^bide 1% W 1000°C liiOO^C 10$ W 1800°C 1200°C 1600°C 0 d. Q.h 1800°C 10$ W 1600°C 1200°C 1$ w" liiOO°C Boron carbide 1000°C only 1000 1200 HOO 1600 1800 10 Calcination tenroerature C t Tiinpsten additive TABLE It.7 COMPOSITION OF OHE SYSTEM B^C - Mo AT DIFFERENT CALCINATION TEMPERATURES Temperature Additive Products 1000 10? Mo M02B^,- B^C . 2Mo/B^C S"- MoB, M0B2, M02B^ 1200 10? Mo M02B^, B^C 2Mo/B^C MoB, ^- MoB 8MO/B^C y - M02B, S- MoB, MOgC 10? Mo lUoo ^°2^5' V 2Mo/B^C ^- MoB, M0B2 8MO/B^C M02B, MoB, MoC 1600 10? Mo M0B2, Mo2B^, B^C 2Mo/B^C S" MoB, /3 - MoB, M0B2 8Mo/B^C M02B, ^- MoB, M02C . 1800 10? Mo M0B2, M02B^, B^C . . . * 2Mo/B^C; S~ MoB, ^ - MoB, •M0B2 8MO/B^C 5*- MoB, phase X with peaks d^ = 2.6, d2 = 2.U856, d^ = 2.36, d^ = 2.19U8, d^ = 1.5, d^ = 1.267, d^ = 1.2526 llil TABIE ii.8 COMPOSITION OF THE SYSTEM B^C - W AT DIFFERENT CALCINATION TEMPERATURES Temperature Additive Products 1000 10$ V7 W2B5, B^C 2W/B^C (f- V/B, W2B5 1200 10$ W W2B5, B^C 2V//B^C V- W2B, (f- BWB^C W2B, ^- V/B, W lliOO 10$ W W2B5, B^C W/B^C y- W2B, v:cr 8W/B^C )f- W2B, S- w 1600 10$ w ^2^5^ V 2V//B^C ^- WB, W2B^ 8W/B^C ^- V/2B, W2C, WC, W 1800 10$ W W2B5, B^C 2V//B^C S -m, ^tJ^B^ WB^O W2B, W2C, WC 11$ generally lower than'those of the niobiijm and tantalum compoiinds and more comparable with those of the vanadium compounds, viz.'M02B^ 2100°C, MoB^ 2100°C, 5- 2350°C, M02C 2la6°C, MoC 2700°C, W^Bg 2300°C, 5'- WB 2liO0°C, WgB 2770°C, VJC 2720^0. Thus, the borides (except V- W^B) can enhance sintering by both surface and crystal lattice diffusion over the whole temperature range studied (1000° - 1800°C); "the formation of carbides is confined to temperatures above about 1200°C for crystal lattice diffusion. l;.3-5 Aluminium additive The effect of aluminivim additive (lOjS) on the sintering of boron carbide in argon at different temperatures is shown in Fig- U.9a and c. For more complete comparison, the broken-lined curve in Fig. U.9a represents the specific surfaces if the aluminium had not reacted with the boron carbide or accelerated (or retarded) sintering. The position of this curve indicates that the aluminium has little or no effect on the sintering of the boron carbide at lOOO^C. This is confirmed by similar experiments in vacuo where the specific siirfaces of the boron carbide sintered for 5 hours alone or with 1% or 10% Al are' 12.12.3 2 -1 and U.l m g. respectively. Increasing the amount of additive has little effect on the sintering, cf. values for 1% and 10^ Al. The aluminium considerably accelerates sintering at 1,200^0 (Fig. U.9a and c), even smaller amounts {!%) being quite effective, cf. curves in Fig. U.9b and d. It has much less effect on idie sintering at higher temperatures (lUOO^C and 1600*^C) where there is considerable activation. At these temperatures the aluminium combines vrlth the boron carbide in contrast to temperatures below lliOO^C vrhere the wetting of the boron carbide surface by the molten aluminium is difficult and incomplete. The cooled samples noii contain no free 116 1600°C IDOO^C 10^ Al 1200^0 1200° C 1800 C 10^ Al 1? Al Boron carbide lliOO^C only lOOO^C TDDT •*T5G5 ' lliOO 1600 1800 globules "of solidified aluminium as were foTond in the samples calcined at lOOO^C and 1200*^C, This behavioxir is in accord with-X^ray analysis, no aliuninium borides or carbide being found in samples calcined at lOOO^C and 1200°C even where there is 2A1 per B^^C present. Hov^ever, there is likely to be some solid solution of Al in B^C at 1200*^C to accelerate sintering, and this is probable at lUOO^C where the X-ray traces do not show any crystalline AlB^, but give somewhat broadened B^C peaks. These correspond to an average crystallite size of 860 S compared vrLth 2000 S estimateji from the surface areas. The calculation from surface areas assumes no particular crystallite size distribution but that from X-ray measurements assumes a Gaussian distribution. The direction of the discrepancy indicates that much of the material has a smaller range of crystallite sizes and/or that the aluminium imposes a strain on the boron crystal lattice. The aluminium boride evidently crystallises and splits off at higher temperatures, causing further increases in specific surface as found for the samples calcined at 1600^0J in v;hich AIB2 has been identified by X-ray analysis, cf. Table ii.9. Some of the carbon formed in the reaction: 2A1 + B^C AIB2 + C may be released as well from solid solution in the boron carbide matrix (as foTind in the oxidation of boron carbide (Chapter 7)) and contribute to the increase in specific surface. The products are more extensively sintered at the higher' temperature of 1800*^0- U.U Electron microscopy data The products of the reactions described above have been examined by electron microscopy, and the data are discussed below. U-U.l Iron additive Comparison with the orginal boron carbide (Plate i^.l) shows that 118 TABLE U.9 COMPOSITION OF 1HE SYSTm B^C - Al AT DIFFERENT CALCINATION TET^PERATURES Temper atitre Additive Products 1000 10^ Al Al, B^C 5A1/3B^C Al, B^C 2A1/B^C Al, B^C 1200 10% Al Al, B^C 5A1/3B^C Al, B^C 2AVB^C Al, B^C ihoo 10^ Al Al, B^C — • 5AV3B^C Al, B^C 2Al/Bj^C • Al, B^C 1600 10^ Al Al, B^C 2A1/B^C AIB2, Al, B^C, phase X v/ith peaks d^ = 2.k96 a. 1800 10% Al . AlB^, Al, B^C 10? Al + S% A1,.^C, phase X with peaks stearic acid = 2.93, d^ = 2.72, d^ = 2.65, . d^=2.52 • . 2A1/B^C (AIN), Al^O^, AlB^, B^C 119 Plate U.l (a) Original boron carbide Magnification: 12000 X (b) Original boron carbide 120 at lUOO^^C (Plate ii.2(a)), the aggregates are becoming larger by coalescing, assisted by the iron boride Fe2B near its melting point, while the crystallites within the aggregates are merging vrLth loss of surface. There are still some crystals T-rith viell defined faces remaining at 1600°C (Plate h»2{h)). Further sintering occurs with some rounding of aggregates at 1800°C (Plate ii.2(c)). When more iron has been present (liFe/B^C), the more extensive conversion of the boron carbide to the iron boride, FeB, and carbon, viz. i^Fe + B^^C = l^eB + C, has left the material in more disperse form, even at 1800°C (Plate it.2(d)) ii.ii.2 Titanium and zirconiuin additives Comparison viith the original boron carbide (Plate U.l) shows that sintering has started at lliOO°C (Plate U-3(a)), but there are still vjide ranges of aggregate sizes at higher temperatures, 1800°C, most of the smaller aggregates have disappeared as is indicated by Plate U.3(b). Some rounding of the aggregates has become apparent and extensive sintering set in. V/here a stoichiometric amount of titanium has been present (2Ti/B|^C), the more extensive conversion of boron carbide to the titanium boride, TiB2, and carbide or possibly carbon, viz. 2Ti + B^^C 2TiB2 + C, has left a mixture of larger crystals and aggregates at 1200*^C (Plate h.3(c)). There are also some small particles of material in the background, possibly free carbon. There is a similarity in the behaviour of the reaction and sintering of boron carbide by titanium and zirconium additives, cf. Plates ii.3 to U-U. Excessive amounts of zirconium react with boron carbide to give ZrBg and ZrC, viz. B^C + 3Zr = 2ZrB2 + ZrC, cf. Table i|.3. U.it.3 Vanadium additive Much finely-divided material is still present at 1200°C (Plate li.5(a)), comparable vrLth the original boron carbide (Plate ii.l) and also 121 Plate U.2 B^C + 10? Fe sintered at liiOO C for 5 hr, Magnification: 12000 X (b) B|^C + 10% Fe sintered at 1600°C for 5 hr. 122. __ Plate I1.2 B|^C + 2;Fe reacted at I80O C for 5 hr Magnification: 12000 X B^C + 10^ Fe sintered at 1800°C for 5 hr 123 Plate ii.3 B^C + 10^ TiH2 sintered at lIiOO^C for 5 hr. Magnification: 12000 X B|^C + 10? TiH^ sintered at 1800 C for 5 hr, 12ii Plate U.3 (c) B^C + 2Ti reacted at 1200°C for 5 hr, Magnification: 12000 X 125 Plate h.h 11 (a) it B|^C 10? Zrfl^ inixture Magnification: 12000 X (b) B|^C + 10? ZrH^ sintered at 1200°C for 5 hr. 126 Plate hM (c) B|^C + 3ZrH2 reacted at 1200°C for 5 hr Magnification: 12000 X (d) B^C + 3ZrH2 reacted at I6OO C for 5 hr 127 having a wide range of aggregate sizes. At lliOO^C the smaller aggregates have disappeared (Plate ii-SClJ). accompanied by a consider• able loss of surface area and corresponding proportional increase in average crystallite size. Extensive sintering and rounding" of large crystal and aggregates is apparent at 1800*^C (Plate U-5(c)); ii-U-ii Niobium and tantalviin additives Vlith the niobium additive there is still some finely divided material present at 1200°C, cf. Plate i;.6(b) . At higher temperatxires, smaller particles start to disappear and aggregates increase in size. Considerable rounding of aggregates-at 1600° and 1800°C is observed (Plate 14.6(c) and (d)). This behaviour is similar to the sintering of boron carbide xvith tantalum (Plates It.7(a) - (f)). VJhere more tantalum has be present {2Ta/B^C), the conversion of the boron carbide to tantalum boride, taB^, and carbon, viz. 2Ta + B^C = 2TaB2 + C, causes pro• gressive disappearance of finely divided material with extensive sintering and rounding of aggregates at higher temperatiires (Platesli.7(c) - '(f))« Molybdenum and tungsten additives Comparison of the original boron carbide and that calcined with 10^ metal additives at 1200°, lU00° and 1600°C indicates sintering and disappearance of smaller aggregates. This also applies to samples calcined with larger amounts of additives in stoichiometric ratios 2Mo/B^C and 2V;/B^C as in Plates h.8 and ii.9. h'h'6 Aluminium additive T!tie aluminium has difficulty in wetting the boron carbide surface, especially at the lower temperatiires 1000°C and 1200°G. Hence the electron micrographs for the 1000°C calcinations still shovj x-jide ranges 128 Plate B^C + 10% V sintered at 1200^0 for 5 hr. Magnification: 16000 X (b) B^^C + 10% V sintered at 11^00°C for 5 hr. Plate U.3 B^C + 10? V sintered at 1800°C for 5 hr. Magnification: I6OOO X 130 P-late ii.6 (a) B|^C + 10^ Nb sintered at 1200°C for 5 hr. Magnification: I6OOO X (b) B^C + 10^ Nb sintered at 1200^C for 5 hr. 1 ^1 Plate U.6 B^C + 10^ Nb sintered at I6OO C for 5 hr. Magnification: I6OOO X (d) B|^C + 10^ Nb sintered at 1800°C for 5 hr. 132 Plate h.l B^C + 2Ta mixture Magnification: 12000 X (b 1 B^C + 2Ta reacted at 1200 C for 5 hr. 133 Plate h'l (c) • B|^C + 2Ta reacted at liiOO°C for 5 hr. Magnification: I6OOO X (d) B^C + 2Ta reacted at I6OO C for 5 hr 13U Plate i;.7 Ik B^C + 10^ Ta sintered at 1600°C for 5 hr Magnification: 12000 X B^C + 10^ Ta sintered at 1800°C for 5 hr, 1 it^ Plate It.8 (a) B^C + 2Mo mixture Magnification: 12000 X B|^C + 2Mo reacted at 1200 C for 5 hr< 136 Plate ^.8 B^C + 2Mo reacted at liiOO^C for 5 hr, Magnification: 12000 X (d) B, C + 2Mo reacted at l600 G for 5 hr. 137 Plate B|^C + 10^ Mo sintered at liiOO°C for $ hr, Magnification: 12000 X (f) y B^C + 10^ Mo sintered at l600°G for S hr, 138 Plate ii.8 B^C + 2Mo reacted at I8OO C for 5 hr. Magnification: 12000 X 139 B^C + 10^ W sintered at 1200°C for 5 hr. Magnification I6OOO X (b) \ 1 B|^C + 10? W sintered at liaOO^C for 5 hr lliO Plate h.9 (c) B, C + 2W reacted at 1600 C for 5 hr Magnification: 12000 X B^C + 10^ W sintered at 1600°C for 5 hr llil . of aggregate sizes comparable with the original boron cai'bide and that sintered vrLthout additives for 5 hours at lOOO^C (Plates U.10(a) - (d)). ii.5 Conclusions At temperatures above 1000*^0, metal additives generally promote sintering of the boron carbide. Their effectiveness is occasionally reduced when there is some surface activation caused by the metals reacting with the boron carbide to form metal borides and carbides of different crystal lattice type and molecular volume- With the possible exception of tungsten additive, sintering of the boron carbide vjith metals at 1800*^C is least affected by any surface activation arising from the formation of metal borides and carbides. Most of the bonding in boron carbide is apparently covalent, whereas bonding in the metal boridss and carbides is much more metallic (cf. Chapter 2). The covalency of the boron carbide inhibits diffusion at the surface and at the grain boundaries (discussed in Chapter 2). Thus, boron carbide particles only aggregate and adhere extensively at ten^eratures above about 80^ of the m.p. in K, ( "^l^OO^^C), compared with about $0% of the m.p.- in K (Tammann temperature) for metals, metal oxides, metal borides and carbides (Huttig> i9Ui), (Glasson, 196?)• The Tammann temperatures for the metal borides and carbides produced in this research are all below liiOO°C and 1800°C, so that they can promote sintering of boron carbide by crystal lattice diffusion at these temperatures. Of the metal additives investigated, iron is by far the most effective in promoting sintering of the boron carbide at IBOO^C, as shown by the much greater changes of crystallites during calcination, cf- Table li.lO. The 5 hour-sintered sample was much harder than tiiose containing the. other metal additives, so that the effect of iron additive on further sintering and densification during hot-pressing vas investigated. This is described in the next chapter. Iii2 . Plate li.lO B^C + Al reacted at 1000°C for 5 hr. Magnification: 12000 X (b) B^C + 2A1 reacted at 1000°C for 5 hr, lii3 Plate U.IO (c) B^C + 1% Al sintered at lOOO^C for 5 hr Magnification: I6OOO X B|^C + 10? Al sintered at 1000for 5 hr. Ihh CHAPTER 5 EFFECT OF ADDITIVES ON THE HOT PRESSING OF BORON CARBIDE 5-1 Introduction The boron carbide produced on a .semi-technical scale (Glasson & Jones, 1969; Jones, 1970) ^•/as mainly of submicron size and sintered appreciably when calcined at temperatures betvreen 1000 1800°C. Sintering was enhanced by increased temperature and tin^ of calcination and also accelerated by addition of chromium at temperatures above 1600*^ and especially at 1800°C. More extensive densificatioh v^as achieved by hot pressing, i.e. heating under a pressure exceeding the critical stress at temperatures relatively close to the m.p. (Dawhil, 19S2j Bryjan et al, 1956). The submicron powders from the magnesium reduction process proved more suitable than the coarser samples given by electrothermal carbon reduction, the latter required ball milling (Jones, 1970) to provide suitable grain size composition for effective hot pressing. In the present work changes in phase .composition and density in relation to time and temperature of mixtures of Bj^C and metal powders when hot pressed have been studied. Mechanism of sintering during hot pressing is discussed in Chapter 2- Correlation of hot pressing with pressureless sintering is discussed by Jones, 1970. Some hot pressing was done on calci\im hexaboride also. 5.2 Experimental 5.2.1 Materials The materials used in this v/ork are the same as those \ised in sintering studies described in Chapter h (Section li.2.l). U45 5-2.2 Procediire Attempts were made to hot press rnixttires of boron carbide + metal po^fder using the laboratory hot-pressing system described in section 3-7.1. Owing to technical difficulties in using this equipment the work was carried out on the industrial system at Chessington and Torpoint described in section 3-7-2. 7 -2 .Samples of CaB^ \jere hot pressed at a pressure of 3-00 X 10 N m for 20 minutes at temperatures up to 2100°C (0.95 X m.p. in K). They were allovjed to cool before removal from the die. The volume of the hot-pressed specimens was determined pycnometrically- The phases present after hot pressing vrere identified by X-ray diffraction- 5-3 Results In the development of hot-pressing equipment, thyristor control of resistance heating was found to be preferable to the conventional satur• ation reactor type, since the former gave a more precise regulation of the sample temperature. The results obtained when boron carbide is hot pressed i-rlth varioixs additives are given in Table 5-1. Densification of the material increased with increasing temperature and time of hot pressing. In the hot-pressing of CaB^ alone densification did not start until a minimum temperature vms reached; this could be regarded as-the yield point or softening point. It then proceeded steadily and reached a maximum of 97% at 2100°C and 2 tons in At each temperature and pressure a maximum density v/as achieved which did not increase appreciably with time. If the temperature and pressure were increased furiher, an increase in density follov^ed immediately. Densities of up to 96 - 9J% of the theoretical value were lii6 TABLE 5.1 Mixture Temp. Pressiire Time .Phases % Theo• °C min. Detected retical Nim density B^C + 10% Al 1000 l.Sh X 10^ No reaction - II tt 1200 3.75 X lo"^ 1 ^ - AIB2 80^ ti 11 1200 i.5ii X 10^ 5 No reaction 66% IT n 1200 10 IT 71% ti If II4OO II 66% It ti liiOO 20 IT 15% IT II 1800 $ ^ - AIB.^2 6S% 11 IT 1800 20 II 79% B^C + 10^ Fe^ liiOO S FeB, 2.988 1x9% 11 II 1600 Fee, FeB Sh% B^C + 10^ Fe"*" II4OO FeB 5S% 11 IT 1$00 FeB II IT 1700 5 Fee, FeB 60% B^C + 10^ ZrHg •1200 5 ZrB2, ZrC S^% •K- 90 mesh iron + finely pox^dered (reduced) iron lii7 achieved. 5M Discussion Iron additives enhanced sintering during the hot-pressing of boron carbide;—analogous to their effect under pressureless sintering conditions . at 1000 - 1800*^C. Nevertheless the densities achieved by hot pressing the 7 —2 boron carbide T-riLth iron under pressure of up to 1,5U X 10' Nm (l ton in at the temperatures used did not exceed fcO? of the theoretical value. It is expected that to reach near maximiam densities, temperatures above 0.8T K will be required (v/here T = m.p. of B^C) (Jones, 1970). This is in spite of the formation of lox-rer-melting iron borides, and the low • wettability of boron carbide by iron. The densification of boron carbide by hot pressing with aluminium additive is more effective at higher press\ire. The combined effect of temperature and pressure help to . overcome the critical stresses and non-wett- ability of boron carbide by aluminiiua (contact angle 118°) (cf. Section 2.7'.-7 Pressure helps also to increase the reactivity between the two substances at this temperature. Thus there is very little or no reaction during pressure sintering (cf. Table h.9)* The formation of AlB^ with a fract• ional volume increase of 0.5397 results in a higher density than the formation of A1B^2 (fraction volume change 5.0766, Appendix IV). Zirconium hydride is a more effective pressure sintering promoter at lower temperature than iron, but less effective than aliiminium (Table 5.1). U8 CHAPTER 6 THE FORMATION AND MICROSTRUCTURE OF BORIDE AND CARBIDE COATINGS ON METAL SURFACES 6.1 Introduction The formation of coatings of borides on metals, alloys and- steel surfaces has been of interest mainly for their wear, abrasion and corrosion resistant properties (Chapter 2), Methods for the formation of such coatings are mainly:- (1) Direct surface boronizing by boron- (2) Reaction vjith boron carbide + alkali metal carbonates. (3) Gaseous boronizing. (h) Boronizing by vapour deposition. In the. present research the formation of boride and carbide coatings on the stu'face of iron and transition metal (Group IVA - VIA) foils by reaction with boron carbide is studied. Improvement in their surface hardness properties and compound formation was investigated at a series of temperatures between 1000° and 1800°C. Possible changes in the reactivity of boron carbide v/ith metals in sheet and fine powder (described in Chapter ii) form are compared. 6.2 Experimental 6.2.1 I4aterials Finely-divided boron carbide, produced by Glasson & Jones (1969), corresponding to an average crystallite size of 0.106/( m (equivalent spherical diameter) has been used throughout this work. Metal foils of very high purity (Goodfellows Metals Ltd.) xvere used. The purity and thickness of the metal foils are shown in Table 6.1. Ih9 Table 6.1 Metal Purity, % Thickness mm Fe 99.5 0.150 Ti 99.70 . 0.125 Zr 99.67 0.125 V 99.91 0.150 Nb 99.92 0.150 Ta 99.96 0.150 Mo 99.95 0.150 W 99.97 0.150 Cr 99.995 0.02 150 6.2.2 Procedure 2 Pieces of metal foils 1 cm in size vzere cleaned in trichloro- propane vapour to frfee them of any grease or dust, rinsed with water and stored in argon-filled plastic bags. Stoichiometric vreights of boron C€Lrbide (suTficient to convert 7S% of metal into boride and carbide, cf. Tables U-1 - h*9) were dispersed in aqueous ammonia. This suspension was transferred to one side of the metal foil to form a uniform coating. They were dried in an oven (110°C) and then heated for a fixed time, xistially 5 h. in argon at different temperatures ranging from 1000° - 1800°C. After X-ray analysis^ the reactedsamples were polished and their micro- hardness values determined (Section 3.8). Selected foils were examined by transmission electron microscopy (Plates 6.1 and 6.6) using a replica technique, and also by means of scanning electron microscopy (Plates 6.2 - 6.5). 6.3 Results Table 6.2 shows the main metal boride and carbide phases formed at different temperatures along vjith their microhardness values. These values are variable where .the reacted sxirfaces of the metal foils consist of different phases in layers. The electron microgrpahs in Plate, 6 show that these coatings are somewhat uneven compared with the initial polished \mcoated metal surfaces, but nevertheless are generally harder for minimising galling of the metal surfaces. .6M Discussion As demonstrated earlier (Vinczeandras, 1969; Ducrot & Poulain, I97O5 Samsonov et al. 1970b; and Oreshkin, 1971), the' boriding in5)roves the microhardness and other mechanical properties of metals. The micro- hardness values determined in the present investigation are expected to TABLE 6.2 CCMPOSITION OF fflE SYSTEMS Bj^C - METAL FOILS HEATED AT VARIOUS TEICSRATURES Products Microhardness SEM . -2 Reference Temperature Coated side Uncoated side System kg mm Plate coated side Fe 1750 B^C-Fe 1000 FeB, (^6.36, 2.911i) 1200 Fe^C (^^3.51, 3.11, 2.3U, 1.18) Fe 1635 268ii B^C-Ti 1000 TiBg, TiC Ti 27hh 1200 TiBg, Tic Ti liiOO TiB2, Tic, (^^2.86, 2.1|8, 2.10, Same as coated Did not retain shape 2.033, 1.86, 1.66, r.S2, 1.312, side 1.311) 1600 TiB^, TiC " TiBg, TiC 1000 ZrBg, ZrC • Zr 28U5 6.1 1200 ZrBg, ZrC 0^2.60, 2.U8, 1.91, ZrC (^2.59, 2.U7, 1.91, 1.U7, 2995 l.li7) 1.36, 1.30) 2630 lliOO ZrB2, ZrC (^2.56, 2.36^ - 1600 ZrBg, ZrC ZrBg, ZrC Did not retain shape TABLE 6.2 ....cont'd Products Microhardness SEM System Temperature Coated side Uncoated side -2 Reference kg mm Plate Coated side B^CV 1000 V^Bg, (^^3.2) V 2225 1200 ^~ VC, V if- VC, Vc, V^Bg, VBg 2300 lltOO V^B^, VC,0^3.U6, 1.7ii, 1.53, V^B^, VC, V (^l.li28) 2500 6.2 1.37) 1600 iT- VC (<^2.37 , 2.05, 1.602) VA Bj^C-Nb 1000 NbB^ 0^2.3li, 1.59) Nb 23I1O 1200 NbBg OO.OU, 2.00, 1.81) NbC (^^3.01, 1.90, 1.78) . 2350 lliOO NbB2, NbC (^^3-02, 2.53, 2.31, NbC (^^1.57, 1.56, l.Ul) 2770 2..11i, 1.77, 1.38 2630 1600 NbBg, NbC (i^3.21, 2.15,-2.Hi, NbC (^^3.65, 2,58, 2.53, 2.29, 2805 6.3 1.63, 1.60, 1.39, 1.29, 1.27) 2.12, I.I49, l.ii3, 1.38, 1.23) 22li5 1800 NbBg, NbC NbC 6^1-59, 1.37, 1.28) 2835 3liii0 • TABLE 6.2 ...cont'd Products ' nic ronarcuie s s SEM System Temperature Coated side Uncoated side Reference mm Plate °C Coated side B^C-Ta 1000 TaBg (^2.17, 1.65, 1.58) y-TaB (^^3.01, 2.30, 1.35) 21^75 1200 5f-TaB 3100 liiOO V -TaB TaC 3288 1600 )r -TaB, TaBg TaBg, (S-Ta^Bj^, TaC, Ta 3512 1800 TaB^ (*3.ii5, 2.38, 1,73, 1.60, 3li65 6.1i i.iiO, 1.3a, 1.30) 2576 B^C-Cr 1600 CrB2,J^-CrB, Crg^C^ Did not retain shape B^C-Mo 1000 ^-MoB, M0B2 Mo 1805 1200 5-MoB, yS-MoB Mo 2250 lliOO (S-MoB (^^2.69, 2.59, 2.35, 2.15, y-MOgB, MOgC . 2385 2.02, 1.89, 1.79) 205ii 1600 (^-MoB, -MoB, M0B2 V-Mo^B, Mo^C 1680 6.5 1730 1800 tT-MoB, >5-MoB, MoBg X-MOgB, MoC (^2.6, 2.U9, 2.36, 2130 2.19, 1.5, 1.27, 1.25) TABI£ 6.2 ...cont'd Products Microhardness SEM Uncoated side System Temperature Coated side i„ -2 Reference Plate °C l B^C-W 1000 y-W^B 0^.59, 1.58) 2I485 6.6 1200 li -WB • fi -WB ("2.76, 2.35) Uh86 2822 lUoo ^-WB, /3-WB, W }f -W2B, W U375. 2850 1600 (T-WB, I^-m /3-WB (^2.36, 2.26) I450O 2910 1800 ft-m 00.76, 2.99, 2.25, 1.90, -WB, WC 3812 1.86, l.lli, 1.09, 1.08) 32iiO ^ Indicates the d spacings in 2 of unidentified phases. Microhardness values were determined only on the coated . side of the.foils Plate 6.1 Zirconium coated at 1200°C for 5 hr. Magnification: 12000 X (b) Zirconium coated at 1200°C for 5 hr. 156 Plate:6.2- Vanadium uncoated Magnification: 500 X Vanadium coated at lliOO°C 157 Plate 6.3 Niobium uncoated Magnification: 500 X Niobium coated at 1600*^ 158 Plate 6.ii Tantalum uncoated Magnification: 500 X Tantalum coated at 1800°C 159 Plate 6.5 Molybdenum coated at 1600°C ybdenum uncoated 160 Plate 6.6 TTingsten uncoated Magnification: 12000 X Tungsten coated at 1200 C 161 differ from those of other workers because of the different compositions of the phases (consisting of borides and carbides) formed on rrietal surfaces. The variation will depend on the relative proportions of borides and carbides and their solid solutions. The adhesion of the coatings on to the metal surfaces will depend on the volume increases when the metals are converted to borides and carbides (Appendix IV) and the wettability of the components of the system. The reactions with individual metal foils are discussed below. 6.U.1 Iron The extent of reaction of boron carbide with iron foil is high compared vrith that of the powdered metal. The formation of FeB on the coated side and the absence of products on the uncoated side of the metal foil (Table 6.2) indicates incomplete reaction,^B^C + hFe = UFeB + C; free carbon possibly forms a solid solution. The microhardness of the coating lies within the values cited in the literature (Katagiri & Fujii, 1971). 6.i|.2 Titanium and zirconium Titanivim forms relatively higher proportions of carbide than boride at 1000*^ and 1200°C with the reaction becoming faster at lUOO*^ and 1600*^C, vAien it is completely converted into boride and carbide. Zirconium reacts similarly to titanium but, tends to form-the carbide at a higher temperatxire and on the uncoated side of the foil. This indicates the preferential diffusion of carbon through the metal and its- boride. There is a slight shift in the X-ray diffraction peaks of the products, showing lattice strain in ZrB2 and ZrC crystals. ZrB^ and ZrC of fine particle size 3500 2 and 7U0 2 respectively, are formed on the uncoated side at 1600*^C (determined by X-ray line broadening. Section 3-1-3) 162 6.^,3 Vanadium, niobium and t-antalum The carbide is formed preferentially on the coated side of vanadium in contrast to niobium and tantalum. Vanadium reacts only slightly at 1000°C, the reaction rate becoming faster at higher temperatures. Niobium and' tantalum react comparatively faster and form borides in preference to carbides, the latter increasing in proportion at higher temperatures and on the uncoated side of the foils. Vanadium foil forms a higher proportion of carbides compared with the metal powder (cf. Tables U.U and 6.2). In the case of niobium and tantalum the products are formed in similar proportions vrtth the foil and powder. Tantalum foil forms lower borides compared x-zith those from the finely powdered metal. A slight shift and broadening of the X-ray diffraction peaks of reaction products of tantalum foil with boron carbide shows crystal lattice strain and formation of very fine crystallites in the range 280 S - 1050 S. 6,h'h Chromium, molybdenum and tungsten With molybdenum and tungsten foils the reaction products are similar to those formed by the reaction of boron carbide with metal powders (Tables U.7, ii.8 and 6,2). Carbides are formed only at higher temperatures and on the imcoated side of foils. Chromium foil being very thin does not retain shape and reacts almost completely at 1000°C. This result contrasts with the reaction with metal powder (Glasson & Jones, 1969b). 6.5 Conclusions At ten5)eratures of 1000*^C and above boron carbide reacts with the metal foils selected in this research work. Reaction at lOOO^C is comparatively slow and remains incomplete during 5 h- heating, being slowest vrlth vanadium. There is a general tendency for the metals of 163 period IV in the Periodic Table to form carbides in preference to borides. This decreases progressively for periods V and VI. Carbides » are formed, in most cases, on the uncoated side of the metal foils (Table 6.2), indicating the preferential diffusion of carbon through the coatings. The development of crystal lattice strain and the particle size (equivalent spherical dianeter) of the crystals is affected by the differences in crystal lattice type and molecular volume of the borides and carbides. X-ray line shifting and broadening show crystal lattice strain in the borides and carbides of zirconium and tantalum and their very fine crystallite size (ZrB^ 3500 2; ZrC 7kO 2; TaC 1959 2 and 'Y- TaB 280 2). In some cases the borides and carbides form separate distinct regions on metal foils and have different values of micro• hardness numbers (Table 6.2). The significance of these results is discussed in Chapter 8 (Section 8.3). 16U CHAPTER 7 OXIDATION OF BOROM CARBIDE, METALS AND METAL BORIDES AND XARBIDES 7.1 Introduction Information so far available on the oxidation of metal borides and carbides has been summarised in Chapter 2, The kinetics and oxidation products depend mainly on the intrinsic reactivity of the material and available surface at which oxidation could occur. Thus, the chemical reactivity of borides and carbides are controlled generally to a considerable degree by the extent to vAich they have been sintered during their formation and any subsequent calcination. The present work extends that of Jones (1970) on the oxidation of finely-divided boron carbide, mainly of submicron crystallite size, used for sintering and hot-pressing with metal powders in Chapters h and 5 and for producing metal boride and carbide coatings on metal surfaces in Chapter 6. It compares the oxidation behaviour of coarser boron carbide, mainly above micron crystallite si2% x-ri_th previous work; Further compar• ison is made v/ith the oxidation of boron suboxide (B^ ^0), since it v/as found that belovf 850°C the oxidation of boron carbide mainly involves boron oxidation only, viz. B^C + 3O2 = 2B20^ + C The coated metal surfaces described in Chapter 5 may contain newly- formed metal borides and carbides and also free boron carbide and metal •where reaction between the latter material has been incomplete at loTxer ten^ratures. Thus, in assessing the sxisceptibility to oxidation and scaling resistance of the coatings, information is required on the 165 oxidation of bpron carbide in finer or coarser sub-division on the metal - surfaces themselves- Oxidation studies have been carried out"therefore - . - ... - on a pTire metal, its hydride and a substrate of it covered vjith boron carbide. Titanium has been selected for these studies. The oxidation of titanixom metal STirface by reaction with finely divided boron carbide has been described by Jones (1970), and was applied to transition metals generally in the present work (described in Chapter 6). The siisceptibility to oxidation and scaling resistance depend primarily on intrinsic reactivity and available siarface for oxidation, but additional factors include changes in molecular volume and type of crystal lattice and sintering of the reactants and products. The extent to which the latter factors are important depends on vdiether the temperature is sufficiently high to permit surface and crystal lattice diffusion, so that increase in surface activity caused by mechanical strain and splitting of crystallites is minimised and sintering is promoted. Changes in molecular volumes when transition metals, metal borides and carbides are oxidised are summarised in Appendix IV. This is complicated if more than one oxide of the metal is fonned, which is illustrated in the present research by further investigation of the oxidation of titaniiim metal compared rath its borides and carbides. 7.2 Experimental 7.2.1 Materials The coarser boron carbide x^as supplied by Koch Light Industries Limited, titanium hydride by B.D.H. and titanium metal by Alfa Chemicals. The boron sub-oxide (B^ ^0) was obtained t»y courtesy of Mr. K.J. Matterson, .Borax Consolidated Ltd., Chessington. 7.2.2 Procedure San5)les of the coarser boron carbide (mainly greater than l^M m 166 crystallite size) were oxidised isothermally in air on a thermal balance (section 3-U). Phases vrere detected by X-ray powder diffraction. 7*2.3 Results Oxidation rates for the coarse boron carbide vieve calculated from weight changes of the samples during calcination shown in Figs. 7-1 - 7-2, Fig. 7*3 sho\-js the oxidation rates for boron sub-oxide calcined in air isotherinally at temperatxires betireen 850^ and 1050*^0. Table 7*1 shows the products of oxidation of titanium foil + boron carbide at various temperatures. Fig. 7.U shows the resxjlts of the oxidation of titanium hydride at 850^C- 7-3 Discussion 7.3*1 Oxidation of boron carbide Below 850*^C, the products were mainly boric oxide and carbon, according to the equation B^C + 30^ = 28^0^ + C, but at 950 - lOOO^C, most of the carbon oxidised to carbon monoxide and carbon dioxide. The right-hand scales of Fig. 7-1 indicate the percentage oxidation of boron carbide on the basis of (l) no combustion of carbon; and (2) complete combustion of carbon. The limited amount of oxidation recorded at 620*^C approxijnated to first or 2/3-order kinetics (these orders being almost indistinguishable from each other for the limited coverage of the initial stages of the reaction). At higher temperatures, the kinetics become mainly parabolic as indicated by the linearity of the plots in Fig, 7-2 of m vs. time, \-AieTe m = fractional increase in x-jeight. The parabolic kinetics at temperatures betvreen 720° and 1000°C are in accordance ^-fith the nechanism of diffusion through the layers of diboron trioxide and any free carbon surrounding the remaining boron carbide. The energy of activation calculated from the rate constants for the parabolic kinetics at 720° and S$0^ for the lovjer temperature oxidation of the 167 ICQ (1) (2) 1000 c a o 3 o o cr CD Time hours Time hours m = fractional increase in weight 1^ 1800 1800 • lOOO^C llAO liiiiO 2 § m o f cr 1080 1080 o *s o 3 720 a- 360 Time hours Time' hours m = fractional increase in weight Fig. 7.3 Oxidation of 2500 2000 1500 0 850°C • 900°C m T 950°C A 1000°C 0 io5o°c 1000 m = ^ Oxidation 500 Tijne/hours j_ I 1— TABLE 7.1 OXIDATION PRODUCTS OF TITANIUM FOIL, SPONGE, AND TITANIUi-I HYDRIDE AT VAPJOUS TEf4PE RAT DUES Temp. Products Temp, Products °C °c . Titanium foil Titanium hydride 360 Ti203 .360 TiO 770 TiO, Ti^O^ 1a30 TiO 800 Ti02 (rutile) 500 TiO, Ti02 910 Ti02 (rutile) 600 TiO, Ti02 950 Ti02 (rutile) 730 TiO, Ti02 (rutile) 1010 Ti02 (rutile) 850 TiO, Tl^O^y TIO^ 930 Ti^O-^y Ti02 (rutile) Titanium foil + B, C 1000 U Ti02 (rutile) 960 Ti02 (rutile) 1050 Ti02 (rutile) Titanium sponp:es U30 . TiO, T^^2^^ h80 TiO, Ti20-j 500 TiO, Ti^O^ 850 • TiO, Ti203, Ti02 171 Fig. 7-a Oxidation of titaniiun hydride at 850 C Hotirs coarser boron carbide is 2h k cal mole"''" (5.7h k J mole '^). The value is similar to that obtained by Jones (1970) for the more finely divided sample at 700°, 750° and 850°C. At hi^er temperatures, viz. 950° and 1000°C, the rate constants give a value of 95 k cal mole""*" (22.73 k J mole""^) for oxidation of the coarser boron carbide sample. The increased activation energy at these higher temperatures corresponds to extensive combustion of the carbon from the boron carbide. 7.3.2 Oxidation of boron sub-oxide Compared x-rith the boron carbide oxidations, the kinetics of sub• oxide oxidation deviate from the parabolic lav; at earlier stages especially at the higher temperatures, cf. non-linearity of the plots of m against time (v;here m = fraction oxidised) in Fig. 7-3- This indicates that the molten boric oxide, B^O^, (m.p- ii50°C) from the boron sub-oxide causes more rapid coalescence of the particles than in the boron carbide oxidation. The effective thickness of product layer through which the oxygen has to diffuse is more rapidly increased, thereby retarding the reaction, so that the oxidation rates of the boron sub• oxide are almost identical with one anotherat 950°, 1,000° and 1050°C. The energy of activation between 850° - 1050°C is 13 kcal mole""^ (3.1 k3" mole""^) Fig. 7-5- Similar results have been obtained for boron nitride oxidation (Glasson & Jayaxireera, 1969; Jayaweera, 1969). 7.3.3 Oxidation of titanium, titanium hydride and titanium + boron carbide The atmospheric oxidation of titanium foil, spong^o^ hydride produces mainly lovxer oxides TiO and Ti^O^ at temperatures below 500°G, cf. Table 7.1. Progressively larger amounts of the higher oxide, TiO^, (rutile) are formed at higher temperatures especially above 850°C x^en 173 Fig. 7 ..5 Arhenius plot for oxidation of 1.6 -. 1.5 l.l» 1.-3 (0 1.2 0) -p •3 1.1 o 1,0 0.5 0.6 0.7 0.8 0.9 1.0 103 • 171* it becomes the main product. Oxidation at these higher temperatures is enhanced by the transformation of the metal from its <^ to - crystal form (transition point 882°C) and by crystal lattice diffusion being facilitated above the Tammann temperatures (f m.p. in K) of the metal (967K, 69h°C)and its dioxide, Ti02 (1096K, 823°C). This eases strain in the material caused by differences in type of crystal lattice and molecular volume betvjeen the metal and its "oxide products, cf. Appendix IV. Hox-rever, the oxidation will be inhibited ultimately by appreciable sintering of the oxide at these temperatures, since this pro-cess is enhanced also by crystal lattice diffusion- Accordingly, the k±netics are paralinear vrlth the parabolic law being limited to between about 5 and 25? of the oxidation of the finely-divided titanium hydride, cf. Fig. 7.ii- Here, sintering of the oxide product is more significant in that it catises coalescence of the small particles of oxide-coated metal hydride and so more effectively increases the thickness of the oxide layer through vjhich diffusion has to occur to maintain the oxidation of the Tinderlying metal hydride. The above oxidation behaviour is analogous to that of titanium nitride described by Glasson and Jayav;eera (1969) and Jayav/eera (I969)- The significance of the Tammann temperature in the sintering and agglo• meration characteristic of oxide masses during calcination processes has been discussed by Glasson (1967). More recently. Stone (1972) has emphasised its significance for the metal in relation to its oxide during metal oxidation generally, as a basis for relating the oxidation processes to the periodic classification of elements. There is some evidence (Glasson & Maude, 1971) that where a netal, e.g. Ni, has a lovrer Tainmann temperature than its oxide, sintering of the oxide is enhanced. 175 The oxide layer can sinter also by means of sxirface diffusion vrtiich becomes appreciable above about "I m.p. in K. Oxidation of titanium boride, TiB^, and titanium carbide also follov/ parabolic kinetics at higher temperatures, analogous to titanium metal and nitride and boron carbide. Recent research on oxidation of zirconiiim boride, ^^^2* alone (Irving and VJorsley, 1968) or x^ith silicon carbide or carbon additives also shows parabolic kinetics (Graham and Tripp, 1970). Thus, oxidations of the metal coatings containing metal borides, carbides and xanchanged boron carbide will follow generally parabolic laws. Hoi-rever, initial rates may be modified by secondary factors described by Gulbransen and Andrevjs (195l) for oxidation of metals and by Coles, Glasson and Jayavreera (1969) (Jayavreera 1969) for oxidation of nitrides. These factors include decreases in the surface heterogeneity as the reaction proceeds, changes in specific surface or in local surface due to the heat of-reaction, solubility effects, impurity concentrations, possible changes in oxide composition and electrical double layer effects. The reactions are initiated by nucleation at defects on the surface after which specific amounts of oxide must be formed, to produce coherent layers. Meanvjhile the reactant surfaces (depending on the specific surface of sample) remain exposed to the gas phase, so that the rates increase and approach linearity, cf. the first of the oxidation of titanium hydride (Fig, 7-^)- When there is sufficient oxide of rational crystallite size composition, it sinters to form surface films through vrfiich normal gaseous diffusion cannot easily occur. The reactions become controlled by solid-state diffusion, xjith the kinetics becoming parabolic and later linear if sintering becomes extensive, as is the case in^the present studies. 176 CHAPTER 8 CONCLUDING SUMMARY This thesis describes the results of investigation into the reactivity of boron carbide tov/ards some transition metals and to oxidation. This research forms a part of a vn.der study of non-oxide ceramics and refractories (nitrides, borides, carbides and silicides) undertaken at John Graymore Chemistry Laboratories, Plymouth Polytechnic (Glasson & Jayavjeera, 1969; Jayaixeera, 1969; All, 1970; Brockington, Glasson, Jayavjeera & Jones, 1973; Brockington, 1973). The reactivity of boron carbide with metal powders and the sintering of the product under normal as well as high pressure is investigated.- The boronizing of metal foils vri.th boron carbide with a view to improving their microhardness has been studied. Oxidation of boron carbide and titanium up to 1000°C has been investigated. 8.1 Pressureless sintering of boron carbide x^ith additives The general effect of metal additives, is to promote the sintering of boron carbide at temperatures above 1000°C arid below its melting point. The changes in crystallite size and shape are correlated with temperatuore and the amount and nature of additive. The differences in the nature of the bonding of the original material and the products bear an effect on the results; so do the differences in the-molecular volume and'lattice type. Iron was found to be the most effective sintering agent. The results are disciissed in relation to those of earlier workers. 8.2 Hot pressing of boron carbide with additives Similar reactions under hot pressing conditions vxere studied and the densities of the products measured. Pressure is an additional factor which promotes sintering and densification. 177 The simultaneous application of pressxire and temperature in an efficient system, V7here high temperatures are followed immediately by a pressure rise, is the most effective means of achieving maximum densification (Stringer & Williams, 1967). For most borides and carbides, including boron carbide, final consolidation of the material is not achieved until a temperature of about 0.9 T is reached (whemT K = m.p.). This is explicable in terms of their increased covalency compared x-rith many oxides and ionic nitrides inhibiting diffusion at the surface and at the grain boundary, cf. incomplete compaction of diamond and borazon (cubic BN) to a pore-free state by sintering vri.th or xid-thout pressure. Compaction of boron carbide withoirt additive to almost theoretical density was achieved only by hot pressing to a temperature above 2300°C (ca 0.95 T) and at pressures o ft O between 12 - 19 tons in" (1.8 - 2.8 x 10 Km" ). This procedure is limited by working pressure of the graphite mould sets, even though the poxirder rapidly consolidates to about 30^ pore density at 1000°C. The resiilts are in accordance with the final densification occuring by a process of plastic flow x^hen the pressure exceeds the critical stresses and causes deformation of asperities at temperatures relatively close to the melting point. 8.3 Microstrxictxire of borides and carbides formed on metal surfaces The^ results'obtained on the formation of boride and carbide coatings on the metal foils shovx -Uiat there is a considerable variation in the nature and composition of the products depending on the particular metal substrate and the temperature. The boride phases ranged in composition from boron- rich to metal-rich ones xjith metals such as tantalum, molybdenum and tungsten, where as the mstals titanium, zirconium and niobium gave a single boride phase of the MB2 composition. 178 Generally, the borides appear to have been formed by the diffusion of metal atoms into the boron network, t^hilst the reverse mechanism occurs for the production of carbides. This phenomenon could be explained by considering the electron availability of the species involved and free energies of the formation of the product phases. The increase in microhardness of the metal when subjected to such treatment can be explained in a similar way and is in line xjith the postulates of Samsonov et al (1970a). The coatings obtained adhered to the metal substrates. The technique represents a process vjhereby machine parts can be 'case hardened'. Since such systems are readily prone to oxidation at elevated temperatures, the exclusion of oxygen is essential unless a protective coating of the product oxide is maintained, e.g. Ti02, Zr02. 8.ii Oxidation of boron carbide and some metal borides and carbides Factors influencing the oxidation of the metals, metal, borides and carbides and unreacted boron carbide in the metal coatings are investigated. The susceptibility to oxidation and scaling resistance depend primarily on the intrinsic reactivity and available surface for oxidations, but addit• ional factors include changes in molecular volume and the type of crystal lattice and sintering of the reactants and products. The extent to i-jhich the latter factors are important depends on whether the temperatxire is sufficiently high to permit surface and crystal lattic^diffusion, so that increase in surface activity caused by mechanical strain and splitting of crystallites is minimised and sintering is promoted. Oxidations of the metals and the components of their coatings are often controlled by solid-state diffusion processes, giving parabolic kinetics which ultimately become linear if the material sinters extensively. Initial rates and 179 kinetics may be modified by secondary factors, which are discussed. The oxidation behaviour of the above materials is similar to that of metal nitrides. The Tammann temperatures of the reactants and products are significant in the sintering and agglomeration of the oxidised material. 6.5 Future developnents Further research vjould be advantageous on. the hot pressing of boron carbide x^ith iron (and possibly cobalt, nickel or chromium) additives at temperatures bettreen about 1900^ and 2300°C (80 - 95? of m.p. boron carbide in K), in i-jhich the composition and densification are correlated v/ith the mechanical strength and hardness. The effect of rational grain size com.position of the original boron carbide on the densification, and how far an optimum grain size composition could be obtained by sintering during production or subsequent milling, would be of interest also. Consolidation of metal borides by cold pressing followed by heating the "green" compact should be studied, using suitable additives to give "cermets", cf. earlier examples of "hard" metals and WC/Cb system (Schwarzkopf & Kieffer, 1960). 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White, J.: "Science of Ceramics", Proc.Br.Ceram.Soc., 1962, 1, 305, ibid., 1965, 3, 155- VJhittemore, O.J.: Trend Eng.Univ.Wash., 1968, 30(2), 28-33. V/icks, C.E., & Block, F.E.: Thermodynamics Properties of 65 Elements - Their Oxides, Halides, Carbides and Nitrides, 1965, U.S. Bureau of Mines Bull. No.605- V/ill, G.: Nature, Lond., 196.6, 212, 175- Will, G.: Electron Technol., 1970, 3(1-2), 119-126, Yukin, G.I.: Metalloved. Term Obrab.Metal., 1971, No.8, 662-66ii. Yvon, K., & Parthe, E.: Acta Crystallogr., Sect.B., 1970, 26(2), Ili9-153. Zaverukha, O.V.: Porosh.Met., 1970, 10(6), U1-U3. Zelikman, A.N., & Loseva, S.S.: Tsvet Metally, Mosk., 19U7, 20(U), Ul. Zelikman, A.N., & Gorovits, N.N.: Zh.Prikl.Khim. SSSR, 1950, 23, 689- Zvrorykin, V.K., Morton, G.A., Ramberg, E.G., Hillier, J., & Vance, A-W. '^Electron Optics and the Electron Microscope". J. Wiley, N.Y., 19U5. XJCLV APPENDICES 1. Computer programme for particle size measurement by X-ray method and table of values of particle size. 2. Computer programme for calculation of thermodynamic functions and tables of thermodynainic data for borides and carbides. 3. Computer programme for graph plotting. ii. Computer programme for calculation of fractional volume change for conversion of metals to borides and carbides and their subsequent conversion to oxides. Fractional volume change tables for borides and carbides. XXV APPENDIX I PARTICLE SIZE MEASUREMENT BY X-RAY LINE BROADENING . • Let bo and B© be the observed breadths of a s-line and a m-line respectively, and ^ the doublet spearation given by: ^ = 0.285 tan 6 © being the angle for maximum diffraction (Bragg angle). The corrections for the -doublet to the s-line and the m-line are given by Jones- (1938) graphic form, ^"^b^ as a'function of ^^t)^, and ^'^BQ as a function of'^^BQ, ijhere b and B are the respective breadths after correction for the -doublet. In this programme, b and B were expressed as an exponential function which was made to fit the cxarve. These values of b and B were used to calculate B>y the intrinsic broadening, from the following relation betvreen ^^B and^^B: ^B = kp ^B = 2p where P ~ " ^ and k is a parameter of particle size. 2(l-k^)^ This equation was solved by the Newton Raphson numerical method to b/ find k values over the desired range of B, in this case 0 to 1. The k value was back substituted to evaluate, thus giving t the particle size. Uie particles vjere assumed to be in the form of cube or spheres^ t is -Uien the cube edge or equivalent spherical diameter. The programme calculates particle sizes from values of % from 16° to 2l4° in increments of 0.1°, and for B^ from 0.27° to 0.1*0 in increment of 0.01°. These ranges for 9 and B^ i-iere the ones usually dealt with in the application of the programme to the work described in this thesis. The ranges of Q and B^ as well as their increment can be changed by XXVI slight modification to the programme. The computer programme is given belov; togeiJier with a page of specimen output. Complete tables are available in a separate folder from Plymouth Polytechnic Library. XXV11 PAGE 2 A.A.CHAUDHRY. 30 FORy,AT(i,ox»lfiEASUREMENT OF PARTICLE SIZE BY THE X-i-RAY METHOOM WRITF.t3i30» AO FORMAT(///,< THE UNITS OF PARTICLE SUE AR£ ANGSTfiOHSM 5 F6fiHATt'?•,7y,'BO•,3X.'0.60•,3X,•0.60',3X1'0.70',3X.•0.80*,3X»'0.9 • 0'.ax.'1.00' ,3X,'I.10*,3»C,U.20'i3x,»l.36'.3X,M,^OS3X.'1.50».3X »,'i.60'.3X,'l.70'.3K.'l.eOM IS FOaH^T(//»U,»TnETAM 0?L r S-o! 285» (Slf^lU.717#3,U29/ie0.0)/COS(U.7l7«3.1429/180.on BSO-0.2^ XS«DELTS/flSO YS'=EAPt0.T95-XS) B5OS>IiS0 A!iGLEM5.9 CO 25 I "1 186 lFCLI\ES-l5T65»60t60 60 WRITEniM ) 11 Fop.:-;MnHn LUifiS-O 65 TtiF.TA " ANGLE +0,1 ANGLEaTHETA THETA-THETA-S. 1 t* PTnia t 2.0-R»:8««3-3.0»R<0««2*l«0)/(l,0-RKG*«2lJfta nTciiT^2.d-3.U3/3£0.0 SIZE»Wft\/EL/(8T"C05(THEtAI » 55 M(L»-SI?E L » L * 1 2 5 W ''1 E ( 3 , 2 0A 3 G L E. 1N (L » . L • 1 • 1 a THETA 429 402 93T 814 721 647 587 537 495 460 16.00 2^*13 1726 1346 1104 W 650 589 539 497 462 431 404. O 16.10 1748 1359 1113 9H4 819 725 653 592 542 499 463 432 405 16.19 2'»98 1770 1373 1122 950 024 729 65^ ?95 5*14 501 670 606 5-f3 •509 472 440 412 16.69 2737 1809 1444. 1170 985 891 7^,9 413 753 673 609 556 511 474 441 16.79 2791 1914 1459 1160 992 856 476 443 415 D 1474 1190 999 862 758 677 612 559 513 16.89 2B'*6 1940 W 561 515 477 445 416 1490 1201 1007 6.67 -r62 680 614 16.99 290'* 1967 O 3 0 73 766 684 ill 563 5i.8 A79 446 417 17.09 0 1995 1506 1211 101<( 419 1022 87S 77 L 687 620 5i5 520 481 448 17.19 0 2023 1523 1222 691 623 ?68 522 483 449 420 17.29 0 2053 1539 1233 1029 884 775 1037 890 780 695 626 570 524 485 451 422 1709 0 2083 1556 1244 PAGE 2 A A CHAUDHRY ' OIM^MSIO.N REAC(0)f SYS(5». OCT {AO J i £<( 40) t WT(AO) RfAU(2•90^^/S 90 FORMAT(12) ' WRIT£13»92) NS • 92 FOgMAT1//////,30X1'NUM3ERV.2X.'OF *.2X.»SYSTEMS"'f121' 2 ReADt2.95)(SVStJ)»jnl,5) 9D FOPMATt 5A2) , WRITEO.??) (SYSt J) f J-1.5) 97 FORMAT(//,3cx.5A2) REiDt2,9C)NR wniTEt3.99)MP 99 FOK.:-'.ATt / /• lOx , 'NUMBER* .SX, <0F* » 2X, ' pOSS 16LE * • 2X , • REACT 2 ONS» • # J 2) 5 READ( 2» ICOHREACt J) I J=l i8) 200 FORMAT (OA'*) w/^ITE(3»102)(REACU)»J=l»8) 102 FORMAT (' i:* .10X» 'REACT I OM' .2K.8AA///1 KE/\0(2»105 1AR1.£ U.CR1.DR:.|^R1'0R1.R.1M ^ READt 2 . 205 )AR3 »3R5.CR3 .Hf?: .C:R3.R3M ' »5 RE^-Ot 2 , !05 J'VPl .ePl .CPl .DPI .^tPl .OPl .PIM 1^ RcAD( 2tlC5)AP2fSP2»CP2tOP2.HP2.GP2.p2,M • § REAO(2,lC5UP3f:?P3»CP3iOi'3.HP3.GP3'»P3M 2 105 FOR»-'AT(rlO,2.F10.5»FlC;5.'.Fl0.1 ) W OA = P1M'^AP1+ P2/PAP2+P3H''AP3- R1 irAR 1-=^2fl'AK2-R3M*AR3 DH = PlM-vBPU P2M-''BD2+P3M'BP3- R 1Bg 1-R 2M''6R2-^ 3i-l*BR3 DC « PlM-fCPl+ P2^^•CP2•^P^,V'»CP3- R1A/('CR1-R2M»CR2-R3M^CR3 Cf? = P1M-CPI+ P2M''DP2 + P3p}*DP3- R 1 MrCR 1-P2(X••0R2-R3M^OR3 CfiS= PlM'«*iPl+ P2»-t*HP2 + P3h^NP3- RlW'HRi-P2M':H;^2-R3N»HP.3 . CHCS DM5-290 125 FOHMATi'tX,lA.0X.Fl6.1i8X.E2&.7»8A,Fl6.i) Jl=Jl+1 1F(MP-Jl)l30»130i5 135 CALL EXIT Ef-JD FEATURES SUPPORTED OriE WORD INTEGERS IOCS '?gUF.''"''T'5AR?AbLES 3.2 • PROGRAM 93^. 'p-hiO CO.-^iPlLATION - ' ' ' ^ REACTION . TI02+2D+2C*TIB2+2CO Temp. K AG kcal. Eq« Constant M k cal 100 97191.5 O.OOOdOOOf 00 ; 0**272.3 200 a932&.7 O.OOOOOOOE 00 10^796.0 300 60993.2 106IS2.L' o.oooooooe 00 1061 7i,. 3 <.oo 7259 7 . 5 C.OOOOOOOE 00 6i.2 I7.i. 0.92O5725E-2a I0t029.9 500 55877,2 10'i7 7 5.5 600 <*75B6.7 o.'fSuniE-io ;05i,3i).9 700 39J50,1 0. 13t>1607F-U 105020.2 000- 31169.6 C.1752030E-1O lO't^iiH. 1 900 0, 2670203r-O7 10?99i,*. 1000 230^6.2 0.9litl7lE-L5 1 00 lt,9i0.5 0.i05i7.-;6H-C2 1200 6072.6 0 5 »6 2 5 1 11 01 io?n9. - 300 -9? /.I 0 1^6 01 761 01 101995.0 ^00 -0fi69.4 2(.20e.OtlE 01 1012 u. y 500 -16T03.6 c 272 3t.27E 03 10t376.? IftOO -P't'iSO. 1 0 noo 95232.*. 3 0 h'A*n\hl t.-6 97S26.9 -'|7A6^ 3 .0.290iV79E 96^u6.0 !?8§ -55010 9 0. 103*|769t 0^ 953^9.9 zooo -62500 0.3?2i*f35t 07 9t 1 78.B -69932 •A- U,2?Ao:o3t 08 92952.7 230O 77jCg.2 9 1671.8 2^00 C.^11357'.E Oa 9C336.2 2500 -9^fi^^.^5 10')b',37£ 09 9u9[f5.9 2600 -99093.6 C.2160O23t23E 09 9?G(i0.9 2700 •1062U.0 C.7:o0505E OV 0 560 1 2&Q0 0 /. (. t. 7 . 3 2900 •12556^);? O.M92860E 10 ft73Jtf.B JOOO •I270{j9.2 C.:917S77£ 01175.7 31O0 •13^2 70.9 0.i9623i7£ 10 3200 79^5B.2 77636.3 3300 •U79H7.3 0.(^3663l4u 10 3t00 •15A701.3 C.e9U210E 75860.0 3500 •161399.2 0. 1213 7'JOE 7?979.3 36C0 :16BC^1.0 0. 16:7362E 720^/v .2 3700 •17^626.7 C, 20932<»5F 1 7ao5v7 •Ifll 156.5 0.26ti0629£ 1 6U01t>.9 ini •107630.*. 0.3316i.7flE 1 63760.'* •I9^0^a.3 0.^05999AE 1 L»0 35 FOt^nATi 12) BGAl>t ?.5) (J(( 1 ) * I«l *Sl) 10 CALL ECFCnt 5.M n »Yt n •235.fO. » ^ 00 20 iolrtjl tJ 20 CALL FPLOriO*. XI I I itl M ) CALL FPLOTU.XAlAXiYMAXl LeL*l lF(L-MU0.3Ci30 40 f.O TO 25 400 FORMAT (//•• PLEASe C/^>»wGE PE/<») 30 CALL SCFORl7,SCFX,5CFY.O,.0.) ^ CALL KHARIX^ iocs '?5U^°'*''T'5AS?2BLES 426 PROGRAM 372 ENO OF CO^PILrtTIOiV // XEO // JOQ LOG DRIVE ' CART SPEC CART AVAIL PHY DRIVE 0000 0006 0006 0000 0012 0001 OOZi* 0002 V2 M09 ACTUAL UK CONFIG 16K // FOR TSw l ici t I -noe I I •C0( I 1 •so?! I 1,0-COS I AOl I ••2-C0S(tj0M I I ) ••2-C05(CO WRlTEhll2?lif?AMFnol.J-1.3I.VFC0.lCLA50n.JMJ-1.3l.A0tn 121 FOR^iATf69x»3A2»2X.h7,i.i2X»3A'ii8X.F7.<»l WRI TEI 3.123IIJOI I ) 123 FO5MATll06X.F7.i) W5ITFI3.123»CO(n REruRM EMO li FEATURES SUPPOSIED 9 ONE h'O^O IfJTEGcRS H COPE REOUIREMEMTS FOP OXIOE aorfOAH M COMJ^OM 212 VARIAIXES 26 OROoRAM 25<» M RELATIVE (-NTRY POINT ADDRESS IS 002F (HEX) END OF COMPILATION DUP •cfJ?"fD 0006"SWS^'U9. DSCNT 0013 PAGE 2 CHAUOHRY DIMENSION MAMEI9.3) .^'A^'.Efl( 3) .CLA50t9.3» tCLASM13» tCLASOIS) .A0lt9J 1 «A0(9t f60<9t iC0(9f .M/0(9) .NAD(7)•OO:I 9)fCOW9X COMMON I.AO .OO.CO.AiOl.flOltCOl.NUO.NAO.Q.MAME.CLASO V.t^ITE 13*991 99 FORMAT ( • 1 BORIPE* . 2 X , • FRAC . VOL. • . 2X.' CRYOT. LA TT . ' .2Xi • L ATT» CO.VST • • •?X.'CSttST.LAT T,•.?X.'L4TT.CONST,•.2X.'OXIDE't2X.•FRAC.VOL.'»2Xi'CRY •TST.LAfl,•,2X.'LATT.CONST.') 98 F0RM^T(9X. 'CMAt;3£' . 6X , < ELEf lENT * . ICX. • 30RIDE' . 2 flX. • OX IDE '///1 1 RcAD(2.100)A».BniCM.AMl,DMl.CMl,NUM,(CLASM(Jl.J-Ti}) AMl«Am*3.U3/lflO.O CM1''CM1'3.1^JM&0.0 100 r0R.'A^Jl3F6|^»l^F'..l.:2.3Ai,) REA8lilioJI"?V( n .D^i ii.coin.Aniti).eouii»coiui..NUO(i)iNAotii*« inKME( 1 f J) . j=l .31 ttCLASOl I. J) iJ-l t3) f i-i*riol DO no lei ,flO AOlI I I>AOiI I I*3. W>3/180.0 BOH I >'aoi 1 n 'S.it,3/iso.o I'.o coim-co)n)»3.i*»3/i3o.o 102 F'OfiMAr(3F(i.t.3F^,l.I2.Il.3A2t3A^I . , 3 REAOl2*102)A&.flO.CB>Adl*BBl*CBl.NUB*NAet(NAMEB(J)iJ>}»3l«(CLASB(JI . 1•J"!>3 ) Aei^AlU'S.HtS/lflO.O CBI*CBM5.163/100.0 106 FOP.MAT(?in 1-1 P- AM-QM.CM.sQRTii.o-cos(Att:i*co5tAMn-cos(BMn»<:ori»uvn*cos(CMi • ) "COSICMl 1*2.0"C0S( AMU •COS(DHn •COS'Ctn ) l/NiiI-1 0 - (A0-9H'CB-SORTtl.O-c5S(ABl»-COS(ABn-COSIB811»COS(BOl»-COSIC •ei)-COStCOi1 • 2.0»C0StABl>*C0SIDB1»"COSlCBl»I1/1HU0*NA0I VFCfl a (0-P1 /P R'-CAoi n "B0( n-co( I) - SORTI i.o-cost AOIu > >«cosiAOI 111 I-COS(DOII in* ICOSlBOH [) )-C0SlC0l ( ! ) I'COStCOl ( I)) •2.0»C0S I ADl 11 ) (•COStiiOM I H«C0 ISlCOn I I ) ) )/(NUO( I M"AO( I ) I vFCO» (5-01/O . . WRITE< 3.107)I NAMED'J)•Jol.S).VFC9.1CLASMtJ»•J-1»3).AM.1CLASBU)•J"I•© i:.31.aB.lMAnEM.jT.jel.3).vFCOi(CLASOtIijI.J=1.3liAOUl 107 FORMM l/3A2.'iX.F7.f,.2X.3Ai4.2X.F7.^.2X«3Ai,.3X.F7.4.5X.3A2»2X»F7,4#2X IX,34*. .flX.F7,i. I W.'?lTE(5.109lftM.flH.eOt n 109 FORMAT! 33A.F7,*,. 17X . F 7 . *,. A2X . F7 • ) wRtTEIS.IinCN.CU.COin 111 rOR.-tAT(33X*.F7.A.T7X.F7,A,A2X.F7,<.) 112 IFlHO-1)115*I 13 .1:5 113 WB"N5-1 IF(rJB-0.C00nil7ill7.U9 117 GOTOl C4LL OKIDEIR.VFCO) lFtNT-.90ll25. 125 »l2e 125 6010112 128 CALL EXIT END FEATURES SUPPORTED ONE WORD INTEGERS IOCS CORE REQUIREMENTS FOR COMMOfi 212 VARIABLES 90 PROGRAM 1050 END OF COWpiuATION // XEQ LATT.CONST. LATT.CONST. OAIDE FRACVOL. CRYST.LATT LATT.CONST ELEMENT HEXAGONAL 3.0160 3.0090 AL20 -0.2300 3.0100 4.0^96 HEXAGONAL ALB2 0.5397 cuaic 3.0090 5.0000 3.2620 4.7 580 ^•0ft96 ^-AL203 1.4768 HEXAGONAL ^.7580 5.6400 /3-AL203 HEXACO^ML 5.5**00 2 2.6000 / .9200 TJ-AL203 . ^0'.L9O2 CUBIC 7,920J 7.9200 7.'.i500 9J-AL203 -*0.1810 - CUBIC 7.9500 T.'JOOO HEXAGCMAL 3.0160 TETRAGONAL K-JgOO AL20 3.0100 CUBIC 5.00CO ALB12 5.0766 4.0496 10.2000 HEXAGONAL £..7ffoO 4.0496 0^- AL203 -0.3724 4. 755.0 HEXAGONAL 5*. 64 00 P-AL:O3 -0.7430 5.6Z0O 22.0(300 CUBIC 7.9200 T5-AL203 -C.7948. 7.9^00 • 7.9200 CUBIC 7.9500 OJ^-AL203 rO.7924 7.9500 7.9500 3,0160 At.20 -0.7928 HEXAGONAL 3.OL6O TETRAGONAL 10.3000 CUBIC 4.0496 10.3000 5.0000 ALB12 <..7230 4.0496 4,7590 14.3300 HEXAGO^^AL 4.0496 0<-AL203 ^0.3336' 6.7580 12.92«0 HEXAGOr^AL 5.6400 yS-AL203 -0.7271 • 5.6400 22.6000 CU&IC 7.0200 ^-AL203 .0.7b21 7.9200 7.9200 7.9500 CUBIC ^.AL203 -0.7796 7.91.00 7.9500 5.5391 0AO -0.4535 CUBIC 5.5391 CUBIC 4.2680 CUBIC 5.0250 4.2680 D.';391 0AQ6 0.2254 5.0250 <,.2fr80 5.0250 BA02 -0.3505 TETRAGONAL hin 6.UlblI 3 HEXAGONAL 2.6990 4.3000 BED 0.3960 2.6990 2.2B56 CUBIC c,. TRIGONAL CE203 -0.256L CUDIC I.. 1 300 . CE02 -0.^,417 ^ DATA SUPPL£MEKT TO Ph.D, THESIS (1975) FORf>lATION AND REACTIVITY OF SOME METAL BORIDES AND CARBIDES A, A. CHAUDHRY. APPENDICES !• Computer programme for particle size measurement by X-ray method and table of values of particle size. (xxxv). 2, Computer programme for calculation of thermodynamic functions and tables of thermodynamic data for borides and carbides, (xlii) 3. Computer programme for graph plotting, (ixxxviii). 4. Computer programme for calculation of fractional volume change for conversion of metals to borides and carbides and their subsequent conversion to oxides. Fractional volume change tables for borides and carbides, (sc). 5, Binary borides in the Periodic Table and properties of important borides and carbides, (cxiii). . / .T • "-.TO TC ;r j:^- ,0- .0 .T' :r: J- ' cj. ':-r ca* (--^)' c=-.- - r- CO ;.si,^TO. 4:0 o::;.;c.' -rir.jo^ sj /.ojr. r: c/v::'.. .or •:o::. nr^i. I.: .0. -T ; joff--- * ^x:::c:o. .XT) • c. o lis: -. • . 3. O.J o. £'-2 J / re .-.r/yo^Tor o ,.-1 r --Ts o J* .0 ... J APPENDIX I COMPUTER PROGRAMME FOR PARTICLE SIZE MEASUREMENT BY X-RAY METHOD AND TABLE OF VALUES OF PARTICLE SIZE PAGE 2 A.A.CHAUDH9Y. Olwr%)C|ofj K( 30 FOi^vAf <40X. tMEASUREwENT OF PARTICLE SIZF. OY THE X-»-RAY METHO^M W*!TFt 3»10) 40 FO^vATU/Zj* THE UNITS OF PARTICLE SIZF ARE ANGSTROVS') 9 FrR'-'Sn'l'.7x, 'DOS3y. '0.50' .3X.*0.6CS3X.'0.70' .3X.*0,R0' ,3>-. • 0' ,3>t» ' l-OO* ,3X,' 1 .10' •3X.» 1.20* .3X. • 1.30' .3X»* ;,i.0» .3.".t' I,50' tSX t,»i.fci>',3X.'1.70'.3X#'1.90'l wiTn?»iii 1/, FO^'.'XTI//, ix, • TMETA' | wrjITF(3.l4) Li.\rs=o ^ • DELT$"ot2H5»(.SlNlK.7l7»3,U29/lGO.O»/COStl'..7l7»3Jl429/inO.O» I e'^^0-0.2'. XS-r.ELTS/nSO Yr.«fx3(o.i05-xs» ?FlLli:Fr.i55t65i60t6O 60 wllTEOiin 11 Foq-.-ATiiHii LU:FS"0 . 65 T^'FT^ a A^'-.uf +0.1 A'-GLfBTHrTA T'-ETA-TM^TA.a. 1,29/180.0 DrLTL»0.2n5»(S N 15 CHNTIMJE L r\^5 - LP!ES*1 25 W'JITfW'JITf f(3.Z0»Ar;GLF.(Na ) .L-l»l't» 20 Fpf?VAT(//,F6.2.3XflAl7J CALL EXIT F"0 FF4TU9ES SUPPORTED TPA-T-fD TRACF &RITH«FT1C TpACE • nvc •^Q!>o INTFGPRS FXTFMD'^O PRECISION' IOCS CO'JF OFOUlREMf'iTS FOR COW'ON .0 VARIABLES 106 PROGRAM 6B6 . F^'O. OF COMPILATION // XFO MFA51JRFWFMT OF PARTICLF SIZF BY TME X-RAY METHOD BO 0.27 0.28 V.29 . 3 w W.31 -.33 .34 V.35 V.36 v.37 G.3L 0-39 THETA a • 6^7 t..7 ^55 4uJ 2^13 1726 1346 liU4 9^7 614 721 16.00 w 6t;: '»97 462 *.31 4 o 2A5& 17^8 1369 1113 81v 725 yd9 U.IO Hi *.05 £24 7:; 0>3 ^ .2 4^3 4:;2 :6.i9 2'»90 i77C 1373 1122 v50 P u 30 7iJ 5-.4 5L1 41J5 434 4;,o 16.29 2543 1793 13d6 li32 757 03? 73V 6w0 5C3 4u7 4J5 0 b 16.39 21>U9 1816 14'J0 1141 vu4 .741 ou3 J w J yL5 4u5 437 16.49 2637 1839 1415 1151 571 411 7^5 u03 507 470 43iJ 16.59 2686 186^ 1429 116w 97il 845 412 7'tv CVO !,-.-3 •5^9 472 440 16.69 2737 ieu9 14*»**. 117w 935 651 753 6V3 wO V i^56 511 4 7 4 441 413 16.79 2791 1914 i45V lies 992 H.5c *.li> 750 6.7 wl2 ^ V w 513 4 ("6 44 3 16.U9 2b46 19A0 1474 115J 999 t;62 Hl6 762 6wC Ll4 JOI 515 477 4M5 16.99 290^ 1967 14';j 12C1 :co7 3.67 417 6c^ 0:7 i;w3 5J.U 479 446 17.09 0 19V5 1506 1211 U14 0.7: ( w 0 • 419 77: 6-V w2C 520 4;>1 44ii 17.19 0 2023 :i23 1222 1022 07L 42U i;23 5wO 522 449 17,29 0 2053 1539 1233 10^5 8H4 775 422 626 524 451 17.39 0 2083 1244 1037 890 6vP 698 629 573 526 487 453 423 0 2113 1574 1255 1045" 896 785 7w2 632 y :6 528 488 454 425 17.59. 0 2145 1591 1267 i;jt>3 902 769 SOC. 7Co 035 i.78 531 490 456 426 17.69 0 2178 1610 1278 1061 79*«. 639 5J1 533 492 458 423 17.79 0 2211 1628 1069 914 7»9 7i-9 920 iOS 713 0^.2 >-3 535 494 459 429 17.89 0 2246 1647 1302 1073 431 527 717 L45 5.6 537 456 461 17.99 u 2282 1667 1315 1^86 6^8 432 933 313 721 043 5J9 540 498 463 la .09 0 2319 1686 1327 1095 434 1707 939 eiG 725 C51 591 542 500 464 18.19 u 2366 1340 1104 435 ,172b •;4L u23 729 wy5 5>4 544 5C2 466 18.29 0 2396 1353 1113 437 1749 9S;3 82ci 733 ii>0 t97 5**7 5J4 468 18.39. 0 2436 1366 1122 470 438 1771 .959 633 737 ;.6l 54 9 506 la.'*9 0 2476 1379 1131 472 1793 96C 635 741 ti5 LIZ 551 508 440 la.59 0 2521 1393 1140 '.73 ICIO 973 7'.5 608 605 554 510 18.69 u 2566 1HW7 1150 475 443 1839 980 849 750 i71 ecu 556 512 in.79 0 2612 1421 1159 445 1863 9b7 t55 754 675 611 558 514 477 le.89 0 2660 1436 1169 ^46 860 758 678 C-14 561 517 479 18.99 0 2709 1887 1450 1179 994 519 461 448 865 763 6d2 617 563 19.09 0 2760 1913 1465 1189 1001 450 871 767 635 620 566 521 483 19.19 0 2814 1938 1481 1199 1009 451 877 771 689 623 568 523 484 19.29 0 2869 1965 1497 1210 1016 4U6 453 882 77.6 693 626 571 525 19.39 0 2926 1992 1513 1220 1024 4tid 455 8U8 7bC 696 629 574 527 19.49 0 2986 2020 1529 1231 1032 456 894 785 700 632 576 530 19.59 0 0 2049. 1545 1242 1039 492 458 900 790 704 635 579 532 19.69 0 0 2078 1562 1253 1047 534 494 460 906 794 708 638 581 .19.79 0 0 2109 1580 1265 1055 496 461 912 799 711 6^1 584 536 19.89 0 0 2140 1598 1276 1063 498 463 918 B04 715 644 587 539 19.99 0 0 2172 1616 1288 1072 465 809 719 . 643 589 541 500 20.09 0 0 2205 1634 1300 1C30 925 5-J2 . 467 814 723 651 592 54 3 20.19 0 0 2239 1653 1312 .1C89 931 504 468 1324 937 819 727 654 595 b^t 20.29 0 0 2274 . 1672 10;97 470 506 944 324 731 657 598 548 20.39 0 0 2310 1692 1337 1106 20. <»9 2347 1712 1350. 1115 950 829 735 661 600 550 508 472 20,59 2385 1733 1363 1124 957 8 34 739 664 603 553 510 474 606 555 20.69 2425 1754 1376 1133 964 639 7^3 668 512 476 609 20.79 2466 1776 1389 1142 971 844 748 671 55b 514 477 612 20.89 •2508 1798 14J3 1152 978 850 752 674 560 516 479 615 20.99 2551 1821 1417 1161 ,985 8 65 756 67B !962 519 4bl 618 565 21 .09 2596 1844 1432 1171 992 860 760 6t»l 521 4b3 021 21.19 2643 1868 1446 1181 999- 666 765 685 566 523 485 624 21.29 2691 . 1892 1<*61 1191 1006 872 769 6b9 570 525 407 21.39 2741 1917 1*76 120.1 1014 877 774 692 627 573 527 489 21. ^9 2793 1943 1492 1212 1021 683 778 696 630 575 530 491 532 493 21 .59 2846 1969 1507 1222 1029 889 7H3 700 633 57b 534 4V5 21.69 2902 1996 1523 1233 1036 e>5 787 7J3 036 580 536 497 21.79 2960 2024 1540 1244 1044 901 vy2 707 639 583 566 539 499 .21.89 3020 2052 1557 1255 1052 907 797 711 642 541 501 913 Q02 715 645 583 21.99 0 0 0. 2082 1574 1266 106U 591 543 503 1069 919 ti06 719 649 22.09 0 0 0 2112 1591 127a 594 546 505 1077 925 611 723 652 22.19 0 0 0 2143 1609 1290 548 507 1085 931 816 727 655 597 22.29 0 0 0 2174 1627 1301 550 509 10V4 936 821 731 659 600 22.39 0 0 0 2207 1646 1314 1103 94^ 826 735 662 602 553 511 22.49 0 0 0 2241 1665 1326 555 513 951 831 - 739 665 605 22.59 0 0 0 2275 1684 1338 nil 558 515 1120 958 837 743 669 608 "2 2.69 0 0 0 2311 1704 1351 560 517 1129 96** b'*2 7'.7 .672 611 22.79 0 0 0 2348 1724 1364 614 563 520 1139 971 847 7i;2 676 22.89 0 0 0 2386 1745 1377 565 522 1148 978 852 756 679 617 22.99 0 0 0 2425 1766 1391 568 524 1158 9b5 858 760 683 620 23.09 0 0 0 2465 1788 1405 570 526 1167 992 063 765 686 23.19 0 0 0 2507 1811 1419 690 573 1433 1177 999 869 769 23.29 0 0 0 2550 1833 629 . 676 531 , 1447 1187 1007 875 774 694 23.39 0 0 0 2695 1857 23.49 2641 1881 1462 1197 1014 880 778 697 632 578 533 • 701 681 535 23.39 26B8 1905 1477 1207 1022 886 7ti3 635 705 584 538 23.69 2738 1930 1493 1218 1029 892 787 638 709 586 540 23.79 2789 1956 1508 1229 1037 898 792 642 713 589 542 23.89 2842 1983 1524 1239 1045 904 797 645 717 592 545 23.99 2897 2010 1541 1250 1053 910 a02 648 720 595 547 24.09 2954 2038 1557 1262 1061 916 b06 651 724 597 549 24.19 3013 2066 1574 1273 1069 922 811 6t)5 728 bvO 552 24.29 3074 2096 1592 1285 1078 V29 816 6tid 733 603 554 24.39 0 2126 1610 1296 1086 V35 821 661 737 606 557 24.49 0 2157 1628 1308 1095 941 b26 665 (xLii) APPENDIX II C 01WTZR Fi^ PGR A:-n--i5 FOR C AII^ULAT I PIT OF THSRMODYNAI-IIC FUNC TIONo Ai€) T A3 LSS 0? T r£>i:R l-iPDY ??.^-:iC D AT A FOR B OR IDES Ai'ID CUBIDES 2 A A CHAUDHRY PAGE DIMENSION REAC(8)f SYS(5)» DGT (40) »(TIC («»0 ) • NT(40) RE:AU( 2»90)N3 90. FORMAT(12» WPITE(3.92) NS 92 FORMAT(//////,30X»'NUMbE7* f2X.•OF *.2X»•SVSTe^'S-•112) 2 ReAD(2f95)(SYS(J)fJ=lt5) 95 FORMAT( 5A2) w»iTE(3.97) (SYSt J .J-LS) 97 FORMAT(//,30X.5A2 RFAD(2»90)MR WPlTC(3t99lNn 99 FORMAT(//,10A,'NUMBER* »2X,'0F»•2X,'POSSIBLES2A••REACT 1ONS»•»I 2 J 5 RFAU(2.100) C^EACCJ) 100 FORMAT(flA4) wPITE(3,102)(REACU)t:,^}t:iV:i6x,'RFACfT0N:;2^,8AW//J = l»8) ^ 102 FORrAc72ii05iARiR ;eiri;c'^si.D^:.H'u.GTU RCAU(2,105)A'O.b:n.C^3.0^J.HR3,0R3 RPAD( 2 1105 J AP 1 »13"1 •CP 1 »0P1 tH.f^l •GP 11*'1'"'. r RrAU 2 051AP2tbP2,CP2.pP2»HP2.GP^ RrAU12.105)aP3,bP3»CP3»U^'J»H?3;G!>3.P3-l FORMAT(Fl0.2»FlU.5.Fl0.6.'»Flo.n 105 Rlv»tRl-R2^'*AX2-R3^''^A.33 DA P i V. B- A C 1 +U2V*A;-^ 2 + ?"'3*'" Riv.»i3r[l-R2-»b?2-K3^*P;.3 Db = Ply •-8^1 + Pi:f.',*9='2+P3^'^e^3- R r.''ClU-R2'-"'Cn2-R3'^;C-<3 DC " P1V'*CP1 + r52v.«CP2 + P3'*''CP3- Rl."."i:r^l-R2^'*D'^2-:^3^"'C13 DO = Piv '(DP1 + P2MitOP2+P3-"^CP2- 0HS = PlV-'tHPl* P2M»MP2+P3V»HP3' DHO = DtiS-29B.0*»DA-(29e.0'»':2)»0b/2-(293-0f»'*3)ft'JC/3.0 00/296.0 DGS° Plv»GPl+ P2M•G?^•^P3v^G03- R 1M»C91-R2^'*r7.2-R3"*C'33 C-.wO I - (DH0-DA'«299.C*ALOG( 29e.0)-'Jb»t 29H.0*''2) / 2.0 -ut ^ ( 29E. 0**3 J /6 10 * DD/(2.0*298.01-DGS)/298.0 DO 120 1=3 .42 NT( l)cioo»(1-2) T«=NT1 I )• +D8*t T *»2)/2.0+0C«C T •»3)/3 X-OD/ T DHT=Dh0+0A» T .«*2)/2.0 •DC*»( T • •3)/ OGT(J)c DHO- T «DAttALOGt T )-D£3»t T 16.0-00/(2.0* T )-COI* T Flf.tn= EXO(-DGT(n/{1.986* T )) 120 WRI TEi 3f 125)NT( n »DGT( I ) »EK-.t 1) iOHT 125 F0R'X^Tt4X# l4»0XfFl6.1»8X.E25.7f8XfFl6.1J Jl^Jl+l IF(NR-Jl)130il30t5 130 L-L+l 1F(NS-L1135»l35f2 135 CALL EXIT END FEATURES SUPJ^ORTEO OME WORD INTEGEKS IOCS CORF REOUIREVENTS FOR 934 COMMON 0 VARIABLES 352 PROGRA-^ END OF COMPILATION REACTION , TI02+2B+2C*T1B2+2C0 Tempo K . G K cals. Eq. Constant H K cals. 97191.5 ou 10'«272.3 2C0 P?326.7 U • C C V b J 0 U L MO io'j7';i),o 300 t099 3.2 vU 106J52.8 <.00 72597.5 O.OOjOC^'CE 00 1061 7/.. 3 500 0.92:5725r -20 106029.9 600 55.!77,2 c. 313 r; 1 E-2: 0 10'j77i,.5 TClO <.7-a5.7 . 101;'.3'*.V BOO 39J 5J, 1 0. 1732C3CE: -10 105020.2 900 • 31169.& 0.2b7O203F-07 , 10'.l>3'i.l 1000 230'.&.2 . 0.912M71E: -C5 103^92. 1.100 l'.9aO.G • 0. 10f)1726c -0? 1033H*j.7 1, 1200 !>';72.6 0.5362biir. -01 102719.B 1300 -077.3 0. li.601 7or (-1 101995.8 uco -a P. 6 9.*. 0.2 -w jj: e c 02 10 1 2 1 • 5 1500 . -16 ? 0 3. 6 C.2723ti;i7F 03 100375.5 16C0 -2'»M^D. 1 o.22i:;-.:f Of. 9VAtj2.'' 17C0 -22199.0 . . 0.13cU-'.12r C'j 9&5 3.':.4 If. 00 -3?'?60,3 0.69i»*-CV.r C'j 9 7 5 ; 6.9 r^co -^yitO'.. 3 C.2-30?97VC 96i..)i.0 2000 • -55010.9 C.103'.7(,9E cv 953'.-''.9 21C0 -6^•.00.X. o.32;;?i.35r 07 9^.17(1.0 2200 -69932.0' 0.e93P'. 6H-- 07 • 92952.7 2300 -7720n.2 0.22tL1^3£: Ot! 91671,0 2^.00 -fl'./ 26.8 . o.5i?p:i7/.r on 90336.2 2500 -9:^•^:^5 0. iuT:t.i7r 09 3*1'!'.'"1,9 2h00 -9';C'.'3.(* C.216CC:..5r 09 8 7 50'-^. 9 -106P**2.0 o.'»;)2"7S(.c 09 2r.co -: 1): 3 i. fi C. 7:t,c ;>95'^ 09 QLi,it 7,3 29C0 -120369.2 0.1 i9>::.oo-7 1(1 • a 2 LJ 3 L'.''. 3CO0 -j."?7?iB.2 C.19:7'^77r 10 . • 81l7-j,7 3100 -13'.;;70,9 0.29i,:3.iVi 10 7 95 P . 2 X 22C0 -i*.n37,r 10. 77686.3 p 3300 -U7yi.7. 3 0.636C?;?!: 10 7i,R6C'.0 t-l* 3f.00 -15C70I.3 0.B911210E IC 73979.3 3500 -161399.^ 0. I21?750r 11 720^.'-.2 < 3600 -iftSC^l.O 0. 101:3N2'^ n • 7005''.7 3**00 -17^.526.7 0.2092L?5=: 11 68 0111.9 3fl00 •-:81156.5 0.266CC.':9.- 11 65912.0 3900 -107630,4 0,3316i.70r; n • 6 37o0.'. 4000 -1940<.a,3 0.'»05999<.S 11 611153.6 REACTION TlCL't+ZOCLS + SHa- TIB2+10HCL 063^2.3 O.OOOOOOOE 00 9917C.8 O.OOUCOCOE 00 96607.5 300 63970.3 O-i^CtjCOuE CO 93teQ.7 f>00 5^.559,1 0.1'.BE552E"i9 90529.3 500 ''5917,0 0.62779^5^-20 87512.4 6C0 3/376,0 0.156Se7G?-13 P'.t65.7 700 30321.9 0.33u';09'jr-09 81700.9 23172.7 0.*.u3216JP.-06 7i;924,0 16366.0 0.1t>55*.97E-O3 76226.4 1000 9353.if 0.7002669E-C2 736^5.9 1100 3595.8 0.192dl9'jE 00 711^7.9 -2^.38.3 0.270196'.E 01 607^.5.2 0.2t67O0jE 02 66'*38.3 !l§8 0.1506;,li!E 03 6^.2:7.7 1400- 0.feUi.5:-51E 03 62113. 1500 -194i.8.9 6C't;'J6 •2te;o.i 0.2'.675t*.F C4 600 0.7375621E 04 5a j76 ,4 700 •3C068 -3S2C5 C.lil92753F 05 1800 t205]7DE 05 5'i6:'?i5 1900 -4C2t5 e7*.2'>l.'.E C5 52998.9 51^67.8 !?38 -6e06 1635I;11F 06 -5'-8tB. .26^?Ol?E 5003'..! -596C6. ,^.6'.7:.2:iE C6 4Ub97.g nil -6**2nB.5 ,7200i32E 06 47^59.1 2'.00 -68920.7 0.1C61'C2'1R 07 46318.0 2500 -73509.6 0. 1 522fi9:E 07 4527*..5 2600 -7e059,fl 0.2C';vv67E 07 4'02a.5 2700 -62577.0 0.2C13225E 07 43^60.2 2300 -87065.*. 0.3675:6vE 07 42729.6 2900 -91529.7 0.'.657263E 07 42076.6 3000 -75973.9 0.t690:60E C7 41521.3 3100 •lOCi.Cl.5 0.7263236r 07 41063.6 3200 •10^.316.5 0.eS26i*.:lE 07 407u3.7 3300 •1092;.2.0 0.105l'r.6'.E ce 404/. 1.5 S'.OO -113621.1 0.1255')90E C9 40277.0 3500 •111^017.4 0,l475UVf: C8 40210.2 3600 -122412.6 0. 1717324E. 00 402tl.l 3700 -126310.4 0.190397iiE CO 40369.8 3800 -131212.6 0.2276t65E 08 40596.2 3900 -135621*6 C.2596360E 08 40920.4 4000 REACTION TIOZ+BZysC tTIBZ+BCO O.OCOOCOOE 00 327251.3 100 30S?06.<» 331 193.8 ?.CiO 209753.6 33:30^.1 300 266736.U o.uuo.oour 00 O.OOOOCCOE 00 33Z94b.3 UQO 2i.7i,32.2 3333ro.5 500 226003,5 C.OOOJOOOF 00 O.tUUuCtUU^ 00 33 J7lf6.0 600 20*.i.<)l,5 334.'1;'..0 700 IB2906.4 334tJ-5.8 BOO 1612'>3.a 33545R.4 900 139516.0 O.l2fel051F-33 11770A,9 O.102in695-J5 33C222.5 95011. O.U97l4l<.?-19 33 7 104.6 1?38 7Jd32.2 0.3'jlC99jr-13 J 311109.1 1200 51764.2 0.196i:7*.£.t.R 339239.0 1305 2960'..5 0. 237i.ri9r-C4 340496.5 lf.00 3410t<3« 1 1500 7350.1 0.14806: •CI -lf,000.6 o.ii?:D07r 03 34 14(0.3 1600 3i*'j0 4U. 8 1700 -37'.50.5 -6C0U1.1 o.i';47:ciF CO 3468L9.3 1100 34SJ7*-2. 3 19C0 -E:2654.'»- 0.32:;'J352E iO -105^.11.7 3507f>0.5 2000 0.335'.421E 12 3529IU.1 2100 -12[.27i..9 0.iJ7vC.UVF 14 2200 -1512'. t..B 351;2M.3 0.1C8C437E 16 3577;0.5 2100 "17i.:23.1 C.373l?4lF 17 2^.00 -197010.6 36U310.0 c.99i6:r>c irt 3610riJ.7 2bOO -22C0tjR,5 o.rt-t,?4b6r: 20 -2'.t217.7 30'^U /i..9 o. 347.'.G It: ;i 366860.7 lfo§ -267739.0 0.i.63in37F 22 -291373.5 0.'j7tJ2*.3TE 23 3719!0.3 2P00 -315121.7 37'.234.6 2900 0.57b«.£d'iF ?4 -33f-9Pt.5 C.51?:f3-F 25- 3 7/16; 3.8 3000 ••3ui >02.5 0.4ClC47u£ 26 38^14d.O 3100 "387056.3 0.2.T1979iiF 27 30:.UC7.2 3200 -411266.6 0.l7y:.63'.F 2fi 3U ;60 1.5 3300 -a3'j594.0 0.iO3T37r ;9 3915,^0.8 3*.00 -*.6C039.0 0.tJ.33:2Ve 29 39 /5'/5. 3 3500 -484601.9 0.2733VeiF 3y 40 1795.1 3600 -509233.4 406U0.0 c.i25i;;?ooF 31 41U6C0.2 3P00 -534O03.n -559003.7 O.543w370!; 21 4152C5.6 3900 -584043.5 0.2208271E 32 419946.5 4000 o.a49f:a20E 32 REACTION 2TI0Z+B4C+3C= 2TIB2+4C0 217247.0 ]00 206171.4 O.OCOOOJOF uO C.UC003CCE 00 223789.0 200 191033.7 22613'..3 300 175283.1 0.0UC03UUE 00 227^33.0 400 ISIlCl.fl ?2D8:i.O 500 40!;6 7.u O.uJULOJUF fU 23UW23.7 600 22r.29.0 o.Ov^vcjor wO ^ 3 1 ?<:0.4 700 Oit362.3 0.174:022^-32 23274-1.5 900 667C1.2 0. 1997204F-23 23'.33'..1 900 68351.7 C.2'.67131F-16 23609 3.0 fc9S16.6" 0. 12769P9F-10 23tU3'j.2 31096.-5. C.6577c7wE-06 240167.3 12191.2, C.6C028'J7E-02 242'.V4.i -6^(99,6 0.1ti75jtE 02 2^5'jin.7 nil. -26177.2 0. 122701'.F 05 <;i.7 7f.3.7 1400 -'.56i.2.3 C.'.5-75'.6F 07 250670.8 500 -65295.7 O.Q39r65CE 09 253^01.'. 600 -85133.4 C.0947525E 11 257136.5 -105171.2 250677.2 0.591'.t2*.E 13 £6''^2^.0 IPCO -125395.0 0.27:^Ci:lF 15 -U5010.6 2683 7 7.5 1900 O.H76;;730F 16 272538.1 -16b'.18.8 0.213591CF lU 20C0 -167220.0 27C9C6.2 2100 -208215.1 o.^c69i5eE • 201tb2.l 22CO -229uOi.,B 0.625971:? 21 2300 -2507S9.2 C.7987L?rC ;:a626s.2 2^00 -272369.3 O.at.'.b^itF 22 2912b0.5 2500 -29M45.5 0.6U9-*7?9E 23 ?96'.5J.3 2f CO -316110.0 0.665rt62CF 2^ 3016611.6 2700 -33U:B7.5 O.'.0U19y2£ 25 3O7(*07,l 2B00 -36065'..3 0. 322ii3UP 26 31331'..3 2900 -383218.9 0.19^56:6E 27 319350.5 30C0 -405J01.5 0. 1071.343F 20 325595.9 3100 -*.:d9t2.5 0.55399C'.E 2d 332050.4 3200 -452102.4 0.26566C6119Lfcyi.E= 2390 3300 -475461.3 50B('0UE 30 3^.00 -499-^19,5 352o69l8 3500 2C5:'?78E 31 -522777.4 7a9?562E 31 359961.7 3600 -5^6735.3 367^.63.1 3700 2y032*.9E 32 -570093.3 ;o2*.93:r 33 376174.0 3P00 -595251.6 383094.5 3900 3484173E 33 4000 REACTION 3TUB4C *2T1B24.TIC -155162,9 100 -154470,4 0.170141 I -153434.0 0* 70141 f -I5^4bi.b 200 0. 701411E -154474,& 300 -152602.4 -1521R0.4 0.1701411E -153021.6 400 0«1701411F -151295-5 500 -152175.0 -152:29,9 0.1701411E -149353.6 600 -14 /2:0.3 700 -153225.4 0.1701411?: -154239,0 0.17014lir -1449C0.0 POO -14?4 23.6 900 -1551.52.8 0.6245130? -157152.3 0,232i44Ci -139771.1 -159J25.5 0.4lli32t? -136953.2 -161162.4 0.233P25eE -133971,5 -163>54.7 0.3252122E -13O027.3 nil -166195.I 0.910C55SE -i27bil.5 1400 -169077.5 Q.4i.50E5:E -124054.7 1500 -172196.5 -12U427.2 .342i-t02E -116639.7 -17S547.2 8 .3ei3i;jJE i^§8 0.577505CE -112692.2 1800 -179125.5 -108565.0 -102'?27.6 0.1131911E 1900 0.276U105'- -104-Id.3 2000 -186750.0 -99C92.2 -191189.8 0.B11C44CE -953C7.0 -19^644.0 0.27y7.6:E -9-^562.5 nil -200310.5 O.llOyiRtE 2300 -ZC5185.7 496313)E -a:659.o 2400 -210270.5 246953(E -8 0596.5 2500 -215 J6C.0 1349247f: -7537i).0 2600 -221C53.3 -69994.7 2700 -226749.0 OCO794:E -64455.5 2eoo -232;4y.3 -5H71J7.5 349 J 5 99?: -5<:900,7 2900 -23a"'«.o.o 3000 2521.1JIE -46L'C5.2 -245334,1 -40710.9 3100 -251*'i24.1 0. r;2 ^03:^ 3200 o.ii4«ci:£ -3^.377.9 -256209.5 -27ijt6.2 3300 -260J69.J O.K09f32*.F 3400 0.1i2l40rF -21235,9 3500 -272162.4 O.Klw527E -1442-6.8 -279427,7 0.940tl592F -7459.2 3600 0.9C2j74(.e 3700 -286(184,3 -332,9 -294531.5 O.B099249E 6951.9 3900 -302368.1 0.B99C451E 14395.5 4000 -310393.8 0.93126iOE REACTION 2TUB^»C= 2TI02+C 100 -119915,7 0.170U11E 39 -120'.19.8 200 -11905*..I 0.17CU11E: 39 -12OC01..6 300 -118353.7 0.170Ullf: 39 -119a76.0 AOO -iiecs.s 0.170Ulli 39 -1181.93.8 500 -119120.8 0. 70U11! -1 6C30.2 600 -119552,8 It -1 1.91.2,1 700 -119316.9 0. nouiir -112055,2 0, lP60iFt6t 38 -1 lU58'v.6 800 -12C?93.1 0.0112'.50r 900 -121765.2 33 -108126.6 -123^.20.!• o.3e5*.*.e9f: 3o -1 J5*.9C.2 0-9755933r 27 -102689.1 1?§8 -1253*»7.I C.U29i.22*.r 25 1200 -127537,0 -99712.0 -129082.2 0.171.29C5K 2'. -9656i.i0 1300 0.7325230r 22 -9321.6.1 1*00 -132676.2 0.;>2;i.692E 21 500 -131-613,^ -B975H,9 -138736.6 0.5091.1.29F 20 -06JO2.8 -1*.2197.7 .9306CE6E 19 -82276,3 eoo -1^.5536.7 8 .1V565C'.E 19 -78265.5 1900 -U9702.3 0.i'216555F 18 -7*.12i..8 2000 -153791,3 0. 1697(,22r 178 -69796,2 2100 -158101.0 0.t5371iOH -65300.0 2200 -162628.7 0.2906Q55F 1? -60636.3 2300 -167372.2 0. i<>6Z£;6i:r 16 -551)05.1 21*00 -172329.S 16 -50n06,5 0.810061.7F -i»5b*.0.6 -177^98,5 0.5031.1.21F 16 il§§ -182877.6 16 -40307.5 2700 -I8t".6'»,9 0.lU370iQ0. 3357<.t2CF 16 -3i.t;C7.2 2800 -191.259.1 0.1*.8i24C5Si'6.237Fr 16 -29139,8 2900 -20C258.e 0.12bll27E 16 -23305.2 3000 -206C62.4 0.112t';i.8E 16 -17303.6 3100 -212£6G.9 0.1037652F 16 -11131..9 3200 -21V477.1 0.9Vo27vvF 15 -4799.2 33C0 -226286,0 0.9eU7379F 15 1703.5 3<.00 -233294.*. 0.1011135F "1 6 8373,2 3500 -21.0501.3 0.1062632r 16 15209.9 -2i»7906.0 0.111.1.927E 16 22213.6 -255507.8 0.1262003F 16 29384.2 Wo -263305.** 0.K.20337 16 36721.8 iloo -271298.5 0.16295C6 16 44226.2 <»ooo -2794.86.0 0.1902631E 16 51897.6 REACTION 3TIO24-3B2O3+10AL* 3TIB2+5AL203 •558911.5 100 -583633.7 0.170U11F 39 -593378.5 o.i7oi4nr 39 •t9i;:6C.3 -590395.6 39 •6 0U 7m7,6 III 0.170U11E •622169.5 -i;n21 0'..6 C.170U11F 39 400 -57UP2fl.O 39 •633666.0 500 0.17wltnE •643^5*..1 -557277.0 0.:7CU11E 39 603 -542077.6 39 •653J1.1.7 700 -5255 04.6 o.nouur 39 •661982.3 •-5G8C49,2 •669961.2 0. WDUilF •677230.0 III -489659.6 0. i7oa6nF 1000 -470553.0 39 •684120.7 0.17014UF •690355.6 1100 -450«fc3.8 0.1701411F 39 1200 -^.306 f 1.5 39 •696049.5 13C0 -410C60,V 0.1701411E 39 -7yl,::3.1 1600 -J89C99. 1 o.noi'.iiF 39 •70513 5'..6 1500 -•»67t'.ii., 7 0.17014 11V' 39 •7097/O. 5 1600 -3463^.9.0 0.170141 IE 39 •7i3v92.5 1700 -:2t£.53.3 0.i70Ull'- 39 •71f.697.2 inoo -302799.0 0. 170U11~ 25 •71V296.1 1900 -2flOS2?.6 0.17-1*. 1 \r. 31 •721392.0 0.7Ctt5:'-9F •7^298:^.6 2000 -25(1753.0- O,3C60315r 27 2100 -236619.2 2u -7260BC.0 -21'*4'.6.6 o.ep;ii7'nr 21 •724675.0 nil -l«225y.O 0.3209309r 10 •724772,1 -17J077.2 0,26^92397 •724372.3 P.II -147921.6 0.3294733^ W •723*.7i, 1 2600 -125f.'j9.5 0. 753 IH.9r •72:(;b'..2 -103758.2 0.276?JB5'I 11 -720197.1 2700 0.15t72U{5 09 2ftOO -81733.1 •717015.3 -59r9b.O 0. l2CQ'?l^r. 07 •71i.'J39.2 2900 0. Ut,fi7r7c 05 3000 -38112.5 •711t;69.1 0.222."»725r 03 -707705.3 3100 O.^Bi>5 7-jlF U2- 3200 5001.1 •70336",i 3300 26476,7 ©.isjiflia-^ -690497.6 3400 47723.3 0,46056t7r .11 •6 93154.2 0.19S151.-0F' -sa73ie.o 3500 • 68809.8 0.1C4297flr' •02 3600 89727.6 -630909,1 O.C6102e9E- -05 -676167.6 3700 • 110467.0 0.497fc3C0t • -06 3800 131021.1 -07 -666054.0 39C0 151381.7 0.*.395124r. .08 -659047.0 4000 0.45027/.3F' 0.5297119E- REACTION TIO2+B203+5MG= TIB2+5MG0 -242667,5 100 -247342.4 0.l70l4lir 39 -24B805.0 C.17CU11E 39 -249819.1 200 -254227.7 300 -247293.0 0.1701411C 39 -244627.^ 0.17Ci4llE 39 -257801.0 400 0.17014:1E 39 -26:920.3 500 -240715.1 -236406.9 O.nOKUF 39 -?637i2.e 600 0.1701411F. 39 -.'66233.1 700 -231653.2 -226555.1 0.17014UE 39 -26Ub0ti.3 800 O.noUllE 39 -270553,7 900 -221185.8 -215600.6 0.170141IE 39 -272378.3 1000 0.17:i4llE 39 -273987.8 1100 -209843.2 0,14u5l72E 38 -203948.6 -?753e6.2 1200 0.1982551E 34 -276576.1 1300 -197945.3 0.9292125E 30 -191859.0 -277559.5 14 00 0,lie'.('9eE 28 -27U33 7.6 1500 -185709.2 0.342C66?r 25 -179514.1 0.195''0l7r 23 -2711911.6 1600 -173239.4 -^•7^28*:.2 1700 0.19695eiF 21 -279453.1 IBOO -167040,7 0.121VC43i' 19 -160804.1 0,794613tE 17 -;!79415.9 1900 -279179.0 2000 -154566.6 G,28C.''954r 16 -148 3•'.5.9 0,13478y6E 15 -27ti742.1 2100 -2781C3.2 2200 -142150.7 0,a501754E 13 23CO -135/09.3 O.6i;0P765r 12 -277265.3 24C0 -129868.4 0,6737692^ 11 -276222.6 -123795.1 -274981.1 -117775,5 C,u04.i'}y7f 10 -1:73539.0 nil -111015.2 0.ll3754eF 10 -271896.5 2700 -105019.2 0.in7l634E C9 -27C053.6 2600 -100092.8 0.352P7o*.F OO -^65010.4 2900 -94340.2 0.752H552E 07 -265767.0 3000 -P.O .65.7 0. 17972nE 07- -.:6;*3i3.3 3100 0.47530''2E 06 -26C679.7 0.138C494E 06' -257835.9 nil -jnii:i 0.436';22yE C5 -254792.0 r 3400 -72149,0 0,1496606c 05 -251548.3 3500 -60;i2 3,7 0.55l4209r 04 -24ai04,5 3600 -61594,3 0.2173104E 04 3700. • -56463.1 -244460.9 -51433.1 0.9116107£ C3 -240617,3 nil -46506.9 0.4052303^ 03 -236573,9 0.1901C39E 03 -232330.5 uooo -41686.7 REACTION ZR02+2B+2C =2PB2+2C0 133733,6 126507.5 O.OUttCOOE CO 100 O.OCCUOOJF 00 135276.9 20C llfi500.5 135704./* 300 1C9999.7 0,00CO300E 00 C.bUt-L-CtOE 00 1350U6-6 COO lOl'.lO.l 13574 1.5 500 92815,7 o.coc'v:c;jr oo 0.157'.6fc7E-30 135562.1 600 8''2'*5.B 13'>29C.6 700 75(13.3 0.222516^F-23 0.'.2Cai4lF-18 13^.936.6 800 67225,'» 13*t512.2 900 58786.1 o.52Ci.ar3r-u 134015.2 50398.1 O.9520773E-11 133'.50.1 }?B§ A2063. I 0.43'.'.245F-Oti 132010.^ 1200 33782.7 0.6977SC2F-C6 132121.1 l?00 26557.5 0.5021255F-C4 131359 1*.00 173GG.5 0. 1922t)l'»F-02 13J533 1500 9276.2 0.4442R40F-01 129G'.3 1221.1 0.6009366? CO 1600 01 120690 1700 -6776.*. 0.7t4l9Ci5E 12767^. -1^.716.0 0.6135147? 02 126595 leoo -22597.5 0.39a0717E 0 3 04 125453.3 1900 -30i.20.5 0,2U9080E 124249.0 20C0 -3aiP*..fl 0.9463'rtOF 0'. 122982.1 2100 -45890.3 0.36429fi3F 05 121652.9 2200 -53536.P 122e671E X2U261.3 -61124.1 371C057E 07 U9t<07.5 ini -69652.2 IC11?-C0F 117291.M -76120.9 25252COE 07 mi -83530.1 5a24i.76r. 07 00 li4072!9 2700 -90H79.6 1252D91t 00 112370.5 -96169.5 1 10606.0 r -IC5399.6 ©.'•ei 7925F 11.3779.5 -112569.8 0.07261G'.=^ SE 106891.0 -119ft.lO.-2 0.150n5f9E 09 3200 -126730.i> 0.24V9-;fiOF 104?40.5 C9 3300 -133720.9 0.39e5975F 102920.0 09 3*»00 -140651,1 0.6134794E 100053,6 09 3500 -1^.7521,1 0.9141271F 98717.2 C9 3600 -154331.0 0.13221S0F 9651B.9 10 3700' -161090,6 0,1B6C715E 94250,6 10 3800 -167769,9 0.2553l23r 91936.5 10 3900 -i7<.398.3 0.3422131E 89552.4 4000 10 REACTION 2RCLi»t2flCL3f5H2 = ZRBJ+lOHCt 130621.6 100 116458.3 12tJ6U7. 1 200 102847.U UULWUU",/E "^0 12 5 3 31,0 300 90657,6 wuCv^j^JE --'0 121C28.6 79625.5 OOCCOOOF 00 400 40864C-1E-30 1133:7.2 69482.6 114835.U 60045.0 13^^515f;-21 188 1024:193^-15 11 14*,3.9 511Q2.6 100146.4 700 42600.1 19Ve39lF-ll 800 3454a26F-O0 104951.4 900 34824.6 1127419F-05 101663.9 1000 27199.4 1117613E:-03 98007.1 llfiO 19877.9 46C5792E-02 96023.0 1200 12922.6 y7b:t.74|;-01 9 1273.0 1300 oOOl.S 1246227C 01 90630.3 -612.0 lGC2'V77r HSj19.5 l'i8 -7041.3 0.65!;6215F U2 05717.3 -13306,4 0,2152691F 02 (13432.0 1^88 -19424, 7 0, 12^2jC5i; 03 U 1 L"64.0 -2'.412.0 0.39U4347E 04 79213.7 inoo -312H1.9 04 1900 -37047.1 o.iii:."^n<6r 05 77:ni.o 2000 -42718.3 0.28i;7775F 05 75466.'* 2100 -4»i306.0 63225C3F 05 73769.9 ??00 -53019.1 i3y^ iiiE 06 721S1.6 2300 -59266.1 25123f.lE 06 70731.6 2400 -Ci»65i*,7 4'jj3.)t;or C6 67390,0 2500 -60991.9 77C55t0r 68166.0 2600 67002.;; -7'^2n4,4 i2^:4',3r 8^ 2700 U7 66076.2 2P00 -8-J530.0 ,i9'.9f,t6E 65^ua.8 -£1'..708.6 0,29<:90f 2F 07 2900 07 64460. 1 r 3000 -9U951.4 0.42b2 /73F 63830.0 -96121.2 0.b03;;769E Q7 3100 07 6 3 ? 1 0. 7 3200 -101272,3 0.03297L6E 62926.1 -106409,3 0.1125*'^'^? 08 3300 08 62652.3 31-00 -1U536.1 0.1i«916V3F 621.97.3 -UU657.0 0.1943346F oe 3500 C8 62461.1 36C0 -121774.8 C.24950i6E 62543.7 -126893.1 0.3159767E OQ 3700 08 62745.1 3P00 -132015.it 0.3954321E 63065*** -137145.2 0.1.896776E 08 3900 08 63504.6 **000 -142284.0 0.60v6ieiE REACTION ZR02+B203+5C = 2RB245C0 356712.6 100 338R22.4 if,\jLij\iO^OE OU 360672.6 2C0 318927.5 O.OOOCOOOF 00 361716.6 300 297743.3 c.OvOcoc;cr ou 362577.6 400 276244.6 O.OCDOOOCE CO 363'J82.2 254601.6 O.OOOOOOOr^ 00 362572.6 500 232860,0 O.OCCt'jwOE 00 6C0 211C32,9 O.OOpOOUOF 00 364109.8 700 189123.9 364724.1 ROO C.OOOCC.OOE 00 16 713 2.4 O.OUL'L'J-OE 00 36'j432.6 900 145056.5• C. 1 50:593E-31 1000 122893.0 • 0.37'jc216F-24 266245.4 1100 10C642.0 . C.4569079E-18 367169.0 1200 78293.7 0,674C243-:-13 36Q207.6 l300 5 5.'16 2.0 O.1881101F-U8 3693t4,3 )4o5 33329.7 0.13U2el2E-0^ 37^641.2 1500 10700,1 0.344*;059:-0l 37;03-^.8 1600 -120?fl.4 0.352094CE 02 373561.4 1700 -34H57,4- C.17U519E 05 375206.7 1800 -57769,2 0.4i.77747c 07 376975,6 1900 -80P22.C 0.607Cf-.4E 09 378071.6 0.66927JCE 11 38Ce92.0 2000 -lC396a;0 0.440*.?iiOE 13 2100 -127203.1 3R303d.3 0.2061279E 15 38 5310.:8 2200 -150552.5 0.7160708^ 16 2300 387709.6 -i74ooa,n 0.I914C4S! 18 390235.1 2400 -197-573,0 0.405eU59F 19 25CO 392807,3 -221245.9 0,70'J2S52E 20 395666.5 2600 -245028.0 0,lCCS7l4r 22 2700 3V057i;,6 -2fr;l920.2 4016U5.9 2800 -292:-23.0 0. 1225202? 23- 2900 0,12fi7262E 2u 404 766.4 -317C37.0 '»0CO54.2 3000 -341262.6 O.I19J22C^ 25 3100 0.963f-C72? 2.5 41 1409.4 -2651:00.5 4 15012.0 3200 -390C5U1 0.7U33127E 20 3 300 0.4643C3:E 27 41i!682.1 3400 ,-414614.7 0.2797139E 2n 422479,6 3500 -439292.0 0,i54960eE 29 426404.6 3600 -464033,3 0.7948730? 29 i.30457,6 3700 -488983.9 0.379R436E 30 434633,0 3800 -514009.2 0.170O291F 31 438946,1 3900 -539144,6 0.7164834E 31 443361.6 4000 -564395.3 4<»7945.3 REACTION ZZROZ+B'tC+SC^ 22RB2+'.CO 126549.6 100 12'*052«2 OOOCOOOE 00 120892,3 0000000"^ CO 120004.2 200 129325.2 3C0 117028.1 112732.7 OOCOOOOE 00 13:653.6 f*00 32145.6 500 lORoes.s OUOtCOOE wO 600 103116.5 2617029E-37 700 97832.2 2699133E-30 5R72190F-25 137793.7 600 9230'..5 14CC08.2 900 86'»02.7 970Ca'.7E-21 2627499^-17 142593.0 1000 e039i..2 145309.0 1100 7tOAa,6 190i:-726E-14 51354S5r-12 140237.2 1200 67^.33. 151377.9 1300 60079,3 64523t5E-10 444t36af.-t8 154731.7 KOO 53^70.3 150293.7 ISOO 461 14,2 1093332^-06 544t 373=:-05 162079.3 1600 395 13.1 166073.5 1700 30669.0 1134792^-03 ie04c69H-02 170201.5 leoo 22063.7 1747C3.4 14259.6 2295172E-01 1900 2333907E 00 179339.1 2000 5695.2 I04la9.0 -3105.3 21055^3^ 01 2100 1610279? 02 199252.9 22CO -12141.9 194530.9 -21413.6 106t,3l2£ 03 2300 0.656'J2?1!: 03 200023.0 2t00 -30919.4 20572'/.4 -4065B.6 0.36C/12Q1E 04 2500 05 21 1649.9 ZbOO -5C630.2 217784,7 -60033.7 8452567E 05 2700 3681431E 06 224133.7 2eoo -71260.4 230697,0 -B1933.7 15076931: 07 29CO 5041921F 07 237474,5 -92029.0 244466.4 3000 -103953.0 2152964E 00 3100 TOBIS^SE 00 251672.5 -115307.6 259093.0 3200 .126fle9.9 256150:E 09 3300 833'iOJ6E 09 266727.7 -138700,4 274576*0 3400 -150739.5 26111499E 10 7970637E 10 282640*2 -163003.9 29C917.9 il§8 -175496.4 0.2356216F II 0.6V79605E 299410,0 3700 -18B215.4 3081 6,5 -201160.0 O.l9025a4E W 3S00 0.5217097E 317037.2 3900 -214332,1 12 ^000 REACTION = 2ZRB2+ZRC 180574.5 0.1701411F 39 002769.7 100 •181531.7 200 17f1B55.7 0.1701411E 39 •IUJWI.O 300 177H05,1 0.17014J1F: 39 177244.6 0.1701411E: •17F621.5 AOO •I7tlj7:.l 500 177090.8 0. izouun 177325.0 l7ni4llE 39 •1 74V12.5 I77i;y5.4 17014111: 39 •172 /'.0.6 ^88 17!)79C.5 0.1731*,nE 39 .17t;37l.7 POO 17'J'>95.9 0.l701f.llE 39 -167707,0 900 101500.3 O.IVOUUE 39 •164992,5 1000 •103294.8 0.2745f1'.5r 37 •101907,7 100 105372.1 0.6034606E ?4 -O•1 58772.b f fc» 7 200 •197726.1 0.37d5&?.6C 22 -155347. 1300 • 190351.9 -151711- , .^ 3 •193244.8 -14?u6b'U65..i0 1188 •19640:.4 0.696'.';i5i: 27 •WOiiO-i, •199818.0 0.5&51530E 26 •139540, 1600 •135062 1700 •203492.0 0.5269796E 25 • 207420.5 0. 74&U;4f.E 24 •13U373 1900 -125474 2000 •211601,4 0.13696;2E 24 0.3133ir/L- 23 •120 364 2100 •2U'J32.5. •115043 2200 •220712.1 0.a.tP 1 224E 22 0.2038576C 22 -10951:; 2200 •225638.2 •103V70.5 2^.00 •230yGS.5 0.1072506E 22 0.46DC:74r -97817.9 2500 .?36224.4 -91654.6 2600 •24;tiyi.6 0.22C75')3r C.llt)9915r -85200.7 2700 .24?779.9 -7('69t;. 1 2P.00 •251910.2 0.67737V2F 2900 •260295.4 0.4245113K -7 1 voce -64094.9 3oro .26;.910.6 o.:fi564?-4r •273762.9 -57671:.3 3100 o.2C4y2:vr -50251.0 3200 -200851.3 0.l5577t2E .28H175.I -42613,0 3300 0.12'.8045C 20 -34 764,3 3400 •295753.6 0.1C4S052r 20 O03526.0 -26704,9 3500 0.9£07Jr6r -18434,8 3600 •311551.B 0.8411325^ -319P10.0 -9954-. 1 3700 .79700O4r -1262.7 3000 .328300.3 8 ,7G096yOE •337022.5 7639.4 3900 0.7093695E 16752.2 UOQO •345975.3 0.e209Ce4E REACTION ,2ZR+B'»C =^2ZR62*C 136666,6 100 -132726,0 0.170U11I: 39 0.170U11E 39 133630.6 200 -131375.8 132172.6 300 -13061 1,'t 0.170Ullfi 39 0.17016 HE -130696.6 AOO • -130307,5 129^07.6 300 -130^01.5 0.1701'. 111; 127106.6 600 -12we55,4 0.17-Ul E II • 126996.5 700 -1316***..2 0.170 161 E 39 •1 22672.6 BOO -132750.1 0.1935906^ 37 •120139.9 900 -13'.159.6. 0.3958600- 33 • 17397.0 0.5130267E 1000 -135062.5 30 . 16663,9 1100 -137r6C.3 0.2537379E 20 0.3616706E •111280.6 1200 -l'.0116,2 •107907.2 noo -U2654.5 O.9Sia310E It 0.5256700E •106.03.7 i*.oo -I'.S'.tO.'t 23 •10C530.2 -1^8529,9 0.65027b3^ 22 1500 0.5690Q:5t -96526,6 -151fi59,3 21 -92312.9 -155'»<.5.5 0.9b9?l62E 20 0.2265310E -87^89.2 -159285.8 -83255.5 -163377.6 0.6366O';0E C,2175G11E !§ -70611.8 2000 -167718.9 19 -73358.0 2100 -172307.7 0.8766206: 0.6052937= in -63096,2 2200 -177162.1 18 -626;0.6 2300 -182220.6 0,2113798^ 0.1226teCE 10 -56936.6, 2'.00 -1875tl.7 10 -51C62.7 2500 -19310'..0 0.77aiC37S 0,53628181 17 -66930,9 -193906,2 -38625.0 -20'*9it7.2 0,3972636E ITo 0.3137665E -32101,2 2800 -211226,0 11 -26367.3 -217761,6 0.2626619F 17 2900 0.231UG9E -10623.6 3000 -22'.692.9 -1 1269.5 -231'.79.3 0.2132303r 3100 0.2C51I63E 1? -3905.6 0.2C69658E 17 3668. 11652,1 il§§ -253H60.3 0.21I9651E 7 0.2262306E 7 19666,1 3^.00 -261759.0 27650.0 3500 -269909,0 0,26a6956E 0.28023B9E 36063,9 3600 -278239.8 A6687.B -286900,9 0,3237709E i; 3P88 0.3826806E 53521.8 3900 -2957^.1.6 17 0,4612081E 62565*7 <»000 -30<»811.6 }? 17 REACTION 3ZR0243B2O346ALn 3ZRB245AL203 100 -'»9ei72,6 0.170141 IE 39 •476071. 200 -506367.7 •501)555. 300 -503376.6 0 W •52^037. ^00 -496187.9 0 17C1^HE 39 •53Ci*16. -(.86622.I 0 •53J075. 500 " wci'.i ir 39 6C0 -i.75672.6 0 39 546138. 700 -(.63179.7 0 170141 IE 39 -552518.6 800 -(.50023.1 17014i7ci..ii1 IeE 39 -55^171.3 -C36197.5 0ll70l4ll17014 E 39 -56Jin2.8 -i.218(.5'.6 0. WOUUF 39 -56 ;60'j.3 1100 -it0T078.0 o.nouuE 39 -571471.6 1200 -391902.0 0.l7Cl4nE 39 -574Q04. 1 1300 -376629. 1 0.1701'.11E 39 -577617.6 I'.OO -361079.8 0.17014 IE 39 -5799»'3.2 1500 -3(.53r!l.O 0.17t;i/. IE 39 -5n i7/:a.G -329579.0 0 . 1 7 C 1i 1 F3 9 -5S30*.C.6 i^S8 -313710.2 O.WvW.llE -i03Ut2.e -29»9G6.8 0.151 jl40E ?? -584 1';9.3 1800 -291097.0 0.278;;3')E 33 -se-^otztd 1900 -266009.1 0.1216'.50E 30 -5834^5.6 -2501 63.(» 0.1122.^C^^F •27 -5E)2319.3 l?§3 -23(.3H1.5 0. 19<;293JE 24 -5d072S.8 2200 -216602.5 0.O191019F 21 -57U076.0 -20?383.3 19 -576 41.0 2300 0.3i92."!e6r 17 2'.00 -:n7599.5 0.2b67754E -573131.6 2500 -i:22'.5.1 0.2069O72C -56V64e.7 2600 -1570:; i..2 0.5229:152r W -565692.8 2700 -1(.1970,3 0.122575ir -561264,5 2P00 . -1270P8.6 0.3fJ3i)'-.46E: \l -550364.2 -112376.*. 0. l5'j.'C9 )E 09 -5509V2.3 r \n% -97fl50.n 0.79C957:?r 07 -5*.51'.9.2 -82521.1 0.5100047E 06 -53Hli35.2 3 300 -69396.5 0.390C55HE 05 -53201;0.5 < 3600 -Sties'..8 0.37035!: iE 04 -524795.2 3500 . -41792.9 O.4O0;)."i5 VE 03 -517069.9 3600.. -2E323.2 0.52573a7E 02 -50'ie74.5 3700 -lb098.l 0.70042b3r CI -500209.2 3fl00 -2108.4 0.13223i5E 01 -491074,2 3900 10635.4 0.2533125E 00 -481469.6 <»000 23126«3 0.b44llBaE' •01 -471395.6 REACTION ZR02+B203+5MG =iZRa2+5MGO -217569.0 0. 1701411E 39 -212106.5 100 -219035.5 200 -219537.i 0. 170U11E 39 300 -218236.3 0. 1701411E 39 -224606.5 400 -215533,6 0. 1701411E 39 -228694.0 500 -211824.5 0. -207431.2 0. 59 -20251a,2 0 39 -236447.6 '78B ::!ir -241175,2 BOO -197196,6 0.17C1411E 39 -191546.7 0 noiAiic 39 -24?679.3 900 -245970.7 000 -185629.3 0 17C1411E 39 -179492.i 0 431 7/.33E " -24e053.7 ,100. -249933.0 1200 -173175.3 0.3614?1JE 32 -166709,4 0.11Ci&5VE 29 -£51611.1 1300 -253090.0 1400 -160121.8 0.1025169E 26 -153435.3 0,233376ir 23 -254371,3 1500 -255455.9 1600 -146669.7 111140CE 21 -139942.4 9739?4«lE 18 -256344,6 1700 -257030.1 IRQO -132968.5 1425'?61E 17 -126061.2 3227?7?F 10 -257537.0 1900 -257U41.6 2000 -119132.6 1C61?1"E 14 -112193.6 4B19?97E 12 -257952.2 2100 -257E69.1 22C0 -1052>3.9 299fl3;9E 11 -96322.3 2229ft2nr 10 -257592.5 2300 -2571^2-7 2400 -914C6.9 .213n6'.E 09 -G4515.0 .246963HE 08 -25£'409,7 2500 -255603.8 2600 -77653.5 0.33S??4UF 07 . -7C92fi,5 C.540r'OOE -25'.554.9 2700 C6 -253313.3 2fl00 -(•4046.0 0.100450HE 06 0,2097enVE 05 -25107e,9 2900 -57311,1 -250251.9 3000 -50629.1 0.'.9C3317F C4 C.127C975E 04 -240432.3 r 3100 -440C4,5 -240420.2 3200 -37441.5 0.3ol9i.49E 03 0.11235;3E 03 -244,'15.5 3300 -3094C.,6 .-24l31ti,5 3400 -24517,3 0.3774727E C2 C.l36'.C6lE 02 -239229.1 3500 -18163.3 -236447,2 3600 -11696.3 0,5272611E 01 O.2160fl02r 01 -233473.1 3700 -5bee.9 -230306,7 3800 425.3 0.9451'.'eiE 00 ,434b3evt CO -226948,0 3900 6453.7 0 -223397.0 4000 . 12393.8 a.2101046E CO REACTION HF02+2H+2C = MF82+2C0 132C66.1 126266.1 O.OOOOOOCE 00 100 O.UUO'^OJOE 132961.6 200 115V97,0 133203.2 107636,0 O.UCUUOUUE 00 133362.6 300 O.CCOOO'JOE 00 90011.6 133277.3 To 9U1Q3.6 133096,6 81500,2 O.10692i;5E-29 600 O,156fi077E-22 132806,7 700 73015.9 132^'l6,1 66500.2 0,233I1997E-17 BOO 0,26200:5E-13 13 19^:5,6 900 56039,3 131260.0 67637.9 O.30269fltF-lO 1000 o.r^3'n2SE:-07 130601.2 1100 39299;7 125Rij7.6 31027,6 0,2217000E-05 200- 0. 1667P1HF-03 129020.6 22823,8 126060.1 16090,2 0.;»C7'.5b?E-'^2 CO 12V006.5 6628.6 o.iooo'>*.rr 125U61.1 -1359,7 0.1536061E 01 02 126622,8 1700 -9273.5 0.1559195E 123 2^^.2 -17111.9 0. 11->V1V0E 03 1800 03 121009.6 1900 -26U7 3.7 0. 7291633E 12U356.6 2000 -32350.3 0.30J'.'P9;'E 1137*.7,2 -60166.R 0. 1522167P ii VC6 4.1 2100 C.5502V9rE 2205 -67o92,5 I 15^^i*7.0 2300 -55161.0 0.176t!5(;2E II 113373.9 2600 -62509,6 0.696152r.E 06 II 13^0-0 2500 -69797,0 0. 127..39VE 07 109331.9 2600 -77005.2 C.259bO';6E 07 107W3,1 -86131,5 0.6i)i;,593r 2700 0.132O57tE 07 1069^2.6 2000 -91175,7 Od 1C.-579.9 -OL-l?3.2 0.25p;22E 2900 0.6^1';;3'.E C8 10vl6b.6 3000 -10501B.3 08 9 7 619.6 -111=115.7 O. 7720i2[.E 3100 0.12l*Je6f.T oo 9 50C 1,6 3200 -113530.1 09 9i:291.7 3300 -125161.3 0.19^7661^ 0.295H95rE C9 BV690,1 36C0 -131709.0 09 BC596.8 -130173,0 0.62951*63?: 3500 0.6035665E 09 8261,1.7 36C0 -166553.0 09 80536.0 -150860.7 0.ti23:651E 3700 0.1092231E 09 77366.2 3000 -167060.1 10 ni05.B 3900 -163186.9 0.l6l2e60E 0.1785089E 10 70753.7 4000 -169220.9 10 REACTION HFCL4^t-2RCl 34&H2 =.HFB2410HCL 100 134162.8 O.OOOOCOOF CO 140985.3 200 120069.7 O.OCCvOOuE CO 146647.6 300 107433.8 O.uCOUOliOE 00 143330.9 400 96061,1 O.UOOuC-OJE CO ,2 98 24,8 500 85529,5 0.2Sl?567E-37 36207,2 600 75706,R 0.2£52053J:-27 700 66473.7 C.lU315;-it'-20 i?9290!6 qoo 57732.7 0.1655362C-15 125E!<11.2 900 49416.3 0,9n4l075E-12 1225i5.2 1000 41470.1 O.0t3fi6l3E-O9 119234,4 1100 33850.2 o.ie647g2r-&6 116C11.1 1200 26520.9 O,14t9C01E-C4 1300 19451.7 0" , 5345016E-C3 1400 12517.4 0, 1C694HE-01 106759.6 1500 5996.0 0. 133617wE 00 103810,4 1600 . -4 31,3 11452P5E 01 100949.1 1700 -6681.7 8: 235995 98152.0 IROO -12769.3 0.355;J95'JE 02 95427.6 1900 -18707.7 0, 1422'!05E 03 92776.0 2000 -24508.I 0,47P2974F 03 90197.3 2100 • -30181,3 0.13e956:'F 04 87691.8 2200 -35737,3 356663-.)E 04 85259,5 2300 -411«4,1 0235759E 04 82900,5 2''00 -46529.7 1736!0^E C5 80614,9 2500 -51781.6 33i»37e2E 05 70^02,7 2600 -56946.5 6160261F 05 76264,0 2700 -62030,5 IU56743F U6 74198.8 2800 • -67039,7 1720P9JE 06 722U7.3 2900 -71978,4 2676845E 06 70209.3 3000 -76252.6 3999373E 06 6844^,0 3100 -81666.5 5765n35E 06 66674.3 3200 -86424,6 O.0C53617E 06 64977,^ 0.1C93652E 07 63354.1 3300 -91130,8 61004,6 3400 -95786,4 0-1448212 07 0.1875209 07 60328.8 3500 -100401,8 50926.7 3f.00 -10497*.,2 0,237yal'^E 07 0.2966177E 07 57598.5 3700 -109508.6 56344.0 3A00 -114008.2 0.3637613r 07 0.4396117I 55163.2 3900 •.lie475,Ct 07 S<»056.3 uooo -122913.3 0.5243371E 07 REACTION HFO2+02O345C = HFB245C0 100 336561.0 O.uOOOOOUE 00 355023.2 200 316424.0 O.OOOOOOOE CO 35P357.4 300 295130.4 O.&OCOCUCE 00 359*'75.6 400 273646.1 O.UOOOCOCE 00 36C113.5 500 251969.6 O.OOCOOOCE 00 36C6ie.O 23C194.5 O.OCOCCOCF 00 36nC5.0 700 208335.7 O.OOOuCUCE CO 361623.9 800 136398.9. O.t'OUUCULE uu • 362199.6 900 1643Q5.n - O.OCCOCOtT 00 362045.0 1000 '42296.6 • O.763605CF- -31 363570.9 1100 120130.6 0.131292iE -23 364380.1 1200. 97fi87,3 0.l4515ft7E -17 361.276.9 1300 75565.4 0. 19i./.fi9f.r.-1 2 366263.6 1400 5?i64,2 0.496391tE- -ca 3673*.2. 1 1500 306R2.5 0, 3364f,63r--04 36t]513.6 lf.00 8119.7 0.77667o?F- •01 369779.1 1700 -14525. I 0. 733626'''F 02 371139.3 1800 -37262.3 O.3:555::E 05 372594.7 1900 -6C063.8 0.81841 l(.E 07 374145.0 20C0 -P2059.2 0.1176721F 10 375793.0 2100 -105T39.3 0. 1075750E 12 3775:36.6 2200 -125004.7 0.6652084E 13 379376.0 2300 -152156.0 0.2';2bl72E 15 301313.8 :400 -175393.6 0.9:'7i.66?E 16 383347,7 2500 -198717.9 0.241CA26E 18 385478.7 26C0 -222129.4 0.4UU-279E 19 307707.0 27CO -245628.5 0.7[t3:656E 20 .390032.5 2PC0 r269215.6 0. 106C-5n6r 22 392455.5 2900 -292H90.9 0. 12in397E 23 394975.8 3000 -316654.0 0. 12072£)9E 24 397593.7 r 3100 • -340507, 5. Ci 10457*.!? 25 400309.3 X 3200 -364649,5 O.BC4Ii,91F 25 . 403122.4 3300 -388450.8 0.553'.660£ 26 406033.2 3400 -412601,9 0.34462;0E 27 409C41.0 3500 -436512.0 • 0.195H0l4r 28 •4 12148.0 3600 -461114.0 0.1022947E 29 415352.1 3700 -485605.5 0.4947645^ 29 410654.0 3800 -509«87.5 0.2229310! 30 422053*6 3900 -534560.5 0.9407a29E 30 425551.2 4000 -569224,2 0.3736799E 31 429146«6 REACTION 2HF02+B4C+3C =2HFB2-* 100 260200,s O.OOUOOOOE 00 272790.7 200 245174,3 O.OCOt:CCOE 00 270116.2 300 220170,2 O.OOOUOOOE 00 20O355.3 400 210529.6 O.OCOOOOOE CO 201924.2 500 192519.3 O.OOOOCOOE 00 203305.9 600 • 17*.234,9 CUtOtJUCf 00 20<*661.5 700 155720,8 O.CUJoOCl'E 00 206060.1 8C0 137001-.2 C.35^)6807E-37 287536.2 900 118090,9 0.202667CE-2e 209100.9 1000 90999.9 0.224.)?37r-21 290709.8 1100 79734.9 0.l406752r-15 292506.1 1200 60301.1 0.102616'-r-io 294502.Q 1300 40702,4 O.1423237E-06 296543.3 1400 20941,9 0.5356697r-03 290709.9 1500 1022,0 0.7C95723F 00 30100b.b 1600 -19055.0 C.402C921F 03 3034Z8.2 1700 -39207.0 0.1131756^ w6 301.962.2 1800 -59674,6. 0.1777219^ 08 308667,3 1900 -80214,3 0( i7067i:r 10 31 1404.0 2000 -100905,7 0, 107U775E 12 31'.433.0 2100 -12171.7,8 0- 4763161E 13 317614.5 2200 -142739,9 0- l5424eiE 15 32U728.9 2300 -163J!S1.1 0.3ni4l23F 16 324076.5 2400 -105170.8 0.74i.7in4F 17 327557.5 2500 -206608,3 o.iiaioncE 19 33 1 1 72.1 2600 -228193.1 0.165fil9CE 20 334920.5 2700 -249924,6 0. 17452/.iE 21 33li8C2.0 2800 -271002.4 C.160fl7e4E 22 342819.0 2900 -293£l26.0 346969,3 0.1433193E 23* 351254.0 3000 -315995,1 0.ioeL746E 2tt 3100 -338309,1 355673.0 3200 -360763,0 o. 73242nr.r 24 360226.2 3300 -303371,2 0,4505605F 25 364913.8 3400 -4061 10,5 0.253flO54E 26 369736,0 3500. -429009,6 C.13l932iE 27 374692,6 -452044,3 0.637193SF 27 379703,7 -475222.2 0.2e769l7E 28 305009.5 ITo -498543.2 0,1220838^ 29 390369.8 3300 -522007,0 0.4093112| 29 395864.9 3900 -545613.:) 0,1060336^ 30 401494.6 4000 0.6736102E 30 REACTION 2HF+B4C = 2HFB2*C -146786.1 100 -146524,5 0.1701411E -145792.1 0,]70141 IE -147310.0 200 - 46170.5 300 -145247,7 1701411E ii 400 -145183,1 17Cl4ll| -144468,1 500 -145582.8 WtUllE -142467.0 600 -146409,2 1701411E 39 - 40241,6 700 -147628,5 17014UE 39 - 377D4.2 ..1701411E 39 -135130.8 0.5296632f? 37 -132290.1 §88 -153397,8 0.350522iE 34 -129267.6 1000 -155964.4 0.1012595E 32 -126C66.7 1100 -158820.0 0.97.8730'/E 29 -122699.5 1200 -161904,5 0. 1770261:E 28 -119137.7 1300 - 65^.19.1 6e90152E 26 -115412.5 1400 - 69126.0 4529e70E 25 -111514,5 1500 -173090.6 4550217E 24 -107444,5 1600 -177333.9 646a467E 23 -1022C2.9 1700 -101B17.9 1226455E 23 -90790,0 IfiOO -196554.8 2^5'>'>«'>E 22 -94236.2 1900 -191537.4 8760C93E 21 -09451.7 2C00 -196762.1 3085299E 21 -84526,7 2100 -202225.5 12619141 21 . -79<.31.3 2200 -2C7924,3 587360CE 20 -74165.7 23CO -213855.7 0.3C;594o(,E 20 -68739.9 2400 -220017.2 0.175at,l6E 20 -63124.1 2500 -226406.4 0.110242.':E 20 -57340.3 2600 -233021.0 0.7*.61067E 19 -51402.6 2700 -239850,9 0.540521'F -45207.0 2R00 0,4160796F -39001.6 2900 -246918,4 1? -32546.5 -254197.& o.23eie7:E 19 3000 o.zye^sJvE -25921.6 5100 -261694,5 IQ -19127.0 -2694C8.1 0.2573386E 19 3200 0.2387(:6i:F -12162.7 3300 -27732e'.T 19 -5020.8 -2854^8,8 0,2296'}6fi^ 19 3400 0.228312OE 2274,6 3500 -293933.2 19 9747.7 3600 -302398.9 0.233e219E 17390.5 3700 -311174,3 0.246C7S3F 25202.8 -320158.8 0.2655390E 1? 3800 19 33104.7 3900 -329351.0 0.2931799E 41336.1 -338750.0 0.3305906E 19 4000 19 REACTION 3HF+B6C = 2HFB2+HFC ICO -35723,2 0,17C161IE 39 -57512.9 200 -16609,3 C,695067*jE 16 -56695.6 300 6706,6 0. 1 29226:E--06 -57213.0 600 28126,7 0,6210765C- •15 -57966.2 500 69736,8 0, 1767202r-•21 -50732.2 600 716^0.2 0,8739^57F- -26 -596JB.3 700 . 93371.0 0.6770a7ir- •29 -60053.0 flOO 115326.7 0.299615PC- •31 -00500.7 900 137335,1 0.62767e5F-33 •-60952.5 1000 1593 02.8 o.i60iioor- .36 -01223.2 1100 181651,5 0.8667869E-36 -61369.6 1200 2035 27.9 0.5162606E- •37 -OKU'9.0 2256C0.B o.ii26iiir- •37 -612(J0.6 1288 267660.5 0.2W69066F:- •20 -61C'.2.5 1500 2696"Q,7 O.UOUUOUJE ou -b06 76.5 1600 291708.1 • o.t;c;.ooocE 00 -60175.7 1700 313002.2 o.ouc:oci.:cr 00 -59:-65.n 1800 335615.5 O.UOOUCCOE 00 -:'0706.6 1900. 357502,0 O.OOC'OOGOC 00 -57091.1 2000 379339,7 . O.OOOUCL'l)?" 00 -56865.0 2100 601122,0 O.UOwOOCuE 00 -55708.2 2200 6 2 i- H 6 6 , 3 0.OOOOOCJE 00 -S**^ 10. 3 2300 66 6 5 0.8. 7 • O.vCuCOCuE 00 -52995.8 2600 666106.5 O.OCCOO^'UE uu - 5 1 6 0. 7 2500 607636.7 00 -69752.9 2.'>00 509006.fl 0. UO..JO(MJE 00 -67972.6 27U0 5306116.3 0 . OwUUUvOF uu -65979,0 2800 551797,1 O.OOOOOOCr 00 -63892.7 2900 573033,0 O.i-'uuuOi.'-E cu -6I6/3.5 3000 596190.0 O.OOOCOCOE 00 -39321.3 3100 6152 06*6 O.OOOJOCuE 00 * -36036.1 3200 636?''0. 7 O.UUUUO'jwF 00 -36217.9 3300 657)71,0 O.vUOOCCCf 00 -3 1666.5 2 6 00 677995,7 0,OOCOCCCE 00 -205P2,1 3500 698733.8 o,oocoo:oF 00 -25506.6 3600 719303.8 0,t;JuOOCOE ou -22613.9 3700 •730966,3 o.oyooomE 00 -19130,I 3000 ' 766616.5 O.UOOOOC-OE 00 -15713.1 3900 700793.0 O.OOOOOOOE 00 -12162.9 <*000 601078*6 O.OOOOOOOE 00 -8679.6 REACTION 3HF02f3B2O3+10AL > 3HFB2+5AL203 100 -502470,3 0. I70U1 IE 39 -475596.1 200 -513367.6 0. j7ci4nE 39 -509 /57.6 300 -511064.9 C. 170141Ir 39 -527415,2 400 -003542.0 0. 170141 IE 39 -5'»0665.3 500 -492729.1 0.170l4lir 39 -551923.7 600 -430167,9 0. 170141 IE 39 -561997,5 700 -465789,4 0.17C1411E 39 -571232.3 900 -45C134.1 • 0.l7C-14nE 39 •-5798C1.0 900 -433439,9 • 0,1701411E 39 • -y97799,l 1000 -415903,U- 0.i7ci4iir 39 -595204,0 noo -397599,6 0.17C1411E 39 -602294,3 12O0- -370699.I 0.170l4liE 39 -606852.5 1300 -359267.5 0.1701411? 39 -614975.0 1400 -339381.0 0. 170 141 IE 39 -620676.5 1500 -319101.6 o.nouiiE 39 -625963.6 1600 -290^02.0 0.17C1411E 39 "63CQ43.5 1700 -277570.0 0.5:7CP62L 36 -635321.3 1600 -255407,2 0. 14 1 3636E 32 -6354C1.2 1900 -235D27.2 0.1122412E 20 -643C06.1 2000 -213463,7 0.2ia7203E 24 -64637B.6 2100 -19174/.,9 0.9265:'.eE 20 -64924:0.5 2200 -169S97.1 0. 7720in£^ 17 -651795.0 2300 -147943,6 0. 1 16437-jr 15 -653919.7 2400 -125905,8 C. 2964934F 12 -655609.2 2500 -103004,0 0. 120ln9CR 10 -657013.6 2600 -81605,0 0.7374p?Cr 07 -657983.2 2700 -59*.76.2 C.6562795F 05 -6'J0569.2 2800 • -37202.6 C.8161145r 03 ..-058772,0 2900 . -15033,6 0. 1373337F 02 -658592.0 3000 7092.6 0.30'*0972P 00 -650029.0 3100 29248,4 0.66452551- 02 -657085.6 3200 51368,2 C. 30970:'ir- 03 -655760.0 3300 734i.0,2 0. 1359077r.- 04 -654053.0 3400 95465,3 0. 725'<300F-06 .-651965.1 3500 117403,0 C.462C355r-07 -649496.5 3600 139275,3 0.3466?63r-Ca -646647.2 3700 161063,4 0.3C25549E- 09 - -643417.5 3BC0 182/58.4 0.30396G4r-io -O39007.7 3900 204353.5 0,3480469C-11 -630817.0 4000 225042.0 0.4501225E-12 -631448.0 REACTION HF02 + B203+5MG = HFB2*5MGO -214695.6 -220287,0 0.1701411E 39 100 0.1701411F 39 -222655.5 200 -222134.6 -227117,2 -220049 0.1701411E 39 300 .4 0.170141 ^ 39 -230632,9 400 -218213.3 0. 70141 f: 39 -233672,8 500 -214740,9 0, 7014 ir 39 -236393.9 600 -210703.9 0. 7014 1? 39 -238U63.2 700 -206223,8 0, 7;il41]E 39 -241 114,5 000 -2t;i405.p 0. 701411E 39 -243166.3 900 -196316,1 • 0. 701411E 39 -245U29.9 1000 -191i;08.-9 .* 0. 61746eE 37 -246712.4 iloo -105523.9 . 0.6O57/.30^ 33 -24U213.5 1200 -179P93.5 0.19556V9^ 30 -249551,5 1300 -174144,5 -2 5'J 7 13.9 -168299.2 0. 194136Cr- 27 1400 0.470C042= 24 -251707,2 1500 -162376,8 -252532.9 -156393.6 0.237CS17E 22 1600 0.21975;;U 20 -253191.8 1700 -150363.9 -253604.8 -144200.1 0.3293959! 10 1800 0,8Cai64?F 16 -254012,4 1900 -138213.5 -254175.3 -132113,9 0.27074381 15 2000 0.1322566S 14 -254173.6 2100 0.829P315E 12 -254007.'B 2200 -.\mn:i 0.6635731" 11 -253673.-1 -113.".21.9 2200 0.6572999- 10 -2521C4.9 2400 -107751.0 0.7U7''C17£ 09 -252520.1 -101704,2 2500 0.11167.^9^ 09 -251700.0 26C0 -95687,0 0.1i:42l2:f 08 -250724.7 2700 -89704,3 0.3480807^ 07 -249570.5 2900 -83761.0 0.7f.3/.t26F 06 .-248269.2 2900 • -77r-61.6 0.1774230^ 06 -246797.0 3000 -72010.1 0.4603468? 05 -245162.1 3100 -66210,4 0.1355355E 05 -243364.5 3200 -60465.'9 0.426^630F 04 -241404,1 3300 -54780,4 0.145C332E 04 -^•39201.1 3400 -49156,7 0.529b007E 03 -236995.6 3500 -43597.5 0.206'.C37F 03 -30106,1 0.e545773E 02 1^88 -32684,9 0,3742276^ 02 -229163.9 -27336.6 0.1726325E 02 -226220.4 -22063.3 0.83306UCE 01 -223130.5 4000 -16867.4 REACTION NB205t4B*5C» 2NBB2-^5CO 100 216207.4 o.uouuoLor 23^^29. 196746.4 •O.UOJUOCOE 780.0 175940.9 O.UCLUOLOE 230809.0 III 233940.0 400 154960.5 O.UCOOO(,0F 133991.9 O.OUCOU(.Or 230657.0 500 • 113105.4 O.OCOCOCOE 238123.8 600 92?23.3 0. 14'.C2( 4t:-20 237407,3 700 71654.4 0.25ccq4Qr-i9 236542,9 800 51101.7 0,39329:3r-12 235549.8 900 234^39.6 3:6'J6,O 0. l9u70VQr-06 JOOO O.U77l:,i.5=:-02 23 3219.6 1100 10346.0 221894,0 -9656.6 0.6254475r 02 1200 0.1Cii9537E C6 230468,4 300 -29945.4 228943.0 -i.9920.6 0.62V2726r 08 400 C, I4y07i2F U 227320.2 500 -6?793,3 225601.5 -89534.8 0. 172t.:^70E 16C0 0.11059;6F 2237B7.0 1700 -109175.7 \l 2^1080.0 inoo -1297C7.3 o.432f;i?ir 16 219870.7 i9no -143130.2 C.1119:)i4E 18 217784,3 2000 -1674t5.3 O.2033775r: 2 ;)'.»97.3 2100 -186653.4 0,273J1(.5P \l 213317.9 2200 -20-:'755.1 0.203w543F 21 210946.6 2300 -224751,2 C.23375:5E 22 208483.5 2400 -243042.1 0.1503 6}OC 23 205920.7 250C -26242C.4 0.90142:4E 23 203202.5 2600 -2011 10.fl o.(.399i;2r 24 200545.0 2 700 -297689.7 0. 19725C 7F 25 197716.4 2PC0- -3151155.4 0.70D4-;i5E 25 194796.6 29no -33-0536.3 0.23:127£9F 26. 191705.0 3nno -35-.809.3 0.72'/4i.i9E 26 1Q06 O.UOtUOOUE 00 679307.6 100 640837,2 609571.6 200 597600,3 O.COCOOUOF 00 O.OUwOOOOE 00 691233.6 300 551436, 1 692482*2 400 504629,6 o.ooccooor 00 457563.0 O.OOOUOOUF CO 693339.1 500 694145.0 600 410333.6 o.soi'caooE 00' 362952.5 O.COU'JOtOF 00 69 50'.5,6 700 696114.0 800 315451,6 o,tct;;oi>jF 00 267794,4 O.OGOOOCOF 00 6973^3.7 900 690900,0 000 219982,9 o.occucoor 00 172001,2 0,63P3873C-34 7Cyp57,5 100 702673,3 2C0 123862.0 0,2581718E-22 75537.1 0.i966C94F-12 704954,8 300 707507,0 400 27026,4 0,6CL4S5-'r-04 -216^6,0 0.14C56C9E C4 710333,6 1500 713437.5 1600 -70576,6 0.4425561? 10 -119679,5 0,2462373? 16 716820.7 1700 72j405.O 1000 -16-J999.6 0.33£'J;i27r 21 -218511,3 C,14K174F 26 724431,6 1900 720661.6 2000 -261)240.0 0,2137765E 30 -313203 0. 1365'.27F 34 733176.0 2100 ,4 727975.3 2200 0.4l:'&9 2 5E 37 -36e3no.5 O.noUllF 39 743C60.2 2-»00 -4l87f12. I 748421.1 2400 0.17014nF 39 -469411,0 0.1701411F 39 7540U0.5 2500 -52:J259,6 760032.6 2600 0.17014116 39 -571360.5 O.IVCUHF 39 766263.0 2700 -622685.3 7727U2.3 2S00 0.17C1411F 39 -674246.3 0.i70l4nF 39 779508.5 2900 -726045.0 3000 0.1701411F 39 706682.2 -779093.5 0.l70l4nE 39 79iC63.8 3100 -D30363.3 3200 0.17t;i4ilF* 39 801733.6 -002085.0 0,170l4lir 39 809691.5 3300 -935652.5 3400 0.17C1411E 39 817937.6 -989664.6 0.170i*.liF 39 026472.0 3500 -1041923.6 3600 0.:701411F 39 835295.0 -1095430,5 O.WCUllE 39 844406,3 37C0 -1149186.2 3B00 0.1701411E 39 853606.3. -1203192.7 0.17C1411E 39 863495.1 3900 -1257450.0 4000 -1311959.2 o.ncuiiE 39 873472.5 REACTION NB2054B6O6C = 2NBB2t5CO 100 227995,6 o.uoxjuooor 00 262J.32.0 W09926.6 C.OOOCOOOF 00 ^6997*:.9 2oo '100265.6 O.uOuO'JUJF L'O 2S203 7.0 300 167067,1 0.U0CUOO3E UO 256179.5 600 160166.U O.COOL'UC'JE to 2556;;9.0 500 126100.0 O.OOOC.'UUf 00 250576.5 600 o.i356D6';r 257057.9 700 io:oi2.3 31 259250.9 79555.6 c,i6e6i73r-2i fiOO 0. :3:oi63r-i3 2OU0'J7.O 900 57116.6 0.3017101E-O7 262567.0 1000 36390,3 0,52l5523F-02 266603.3 1100 11632.5 C.1305519E 03 206622.5 |oo- -11610.6 0.739O033F CO 26l"970.9 300 -36090.3 10 271532.6 1600 O.13t-6900F -5U350.9 0.9C58595F 12 2 76310.7 1500 -82018,2 15 27 73VJ7,6 600 C.296 vtlVK -105870.0 0.5167fl53E 17 200526.3 -129915.9 0.&3*'0'530r 19 2039O2.U IROO -156157.6 2076i?3.9 1900 -176596.5 CSS-JI^OOE 2000 0, 166690.5F 291500.5 -203233.9 0.561U002F 26 29 5617.2 210Q -220071,1 22C0 0.1661679E 299950.6 -253109.3 O 3065U9.1 2300 -270369.6 .29150l7r I'. 26D0 0.679C193E 20 309293.2 -203793.0 65V'. !.2 5r 3 1^303.1 2500 -329660,5 29 2600 7631025E 30 319539,1 -355292.8 769072JK 3 2 5CU1.5 2700 -30 1355,e 31 2C00 .-607615.6 Od30705E 32 3 3U090.5 2900 -636007,3 56C5956E 33 330606.1 3C00 -66C766.9 2059661E 36 36 2 76 0.0 3100 -607655.-1 25!CfieJE 25 369118,1 -516752.5 15C1663E 36 355716.8 Ull -5t.2059,5 032O3'.9E 36 362530.7 -569576,0 630U35iE 37 369509.8 3600 0,2005737? 370868.6 3500 -597306,8 30 -625266,0 0.9566360E 3B 386376.3 3600 -653396.8 0.1701611E 39 392107.8 • -601757.8 0.1701611E 39 6Uu068.e IXo -710333.2 0.1701611E 39 608257.5 3900 -739121.5 0.170U11E 39 416o73.7 AOOO REACTION 2NB+B*»C = 2NBB2K 100 -70639,9 o.nouuE 39 -72339.4 0.170U11F -71259.5 200 -69it*.6.0 -69971.8 300 -anaoe.1 0.17C W.11F uOO 0.3371000F -68435.5 -6Bfct4,7 0.135V337E -66642.4 500 -60899.2 -645ii5.9 600 -6V5 39.0 0.2210237F 700 C.1C5CU9E -62276.7 -705^.3.1 0.4C95515E -59702.3 eoo -71996.7 0.75U9633F -56866.3 900 -73508.5 0.3422052F -53768.6 1000 -7561Q.2 314^^5 14F -504C9.0 1100 -7795*..'8 i.906369E -46787,5 200 -80616.8 1151510E --.2904.0 300 -93591.6 3713590E -30758,4 -86975.2 -343'>0,7 1580 15''3y73E -9Ji.6''.*» 7870C99F -296U0.9 600 -9'.356,2 -2'»7i.9.0 700 -9Q5'.B.0 *.7^.9'.25E IfiOO 0.3294792F -19655.0 -103037.7 0.25fi9091F -14098,8 1900 -107823.2 -8380,5 2000 -U2902.9 0.2211521F 2100 0.207l3e3F -2400.0 -118275.0 0.20C.tol32F 38^.2.6 0.2237197E 10347,4 ll°ol ••iinn-.h 17114.4 •13S132.4 0.2534081E 2400 0.3ail2fl2E 241^3.6 2S00 -U;661.2 0.373256?E 3 14 34.9 26C0 •lt';i»76,5 0.40U26C/F 30988.4 2730 0.63e7fl83E ^6604.2 2800 -156577.2 54e82.1 2900 -163962.5 O.0751975F -171631.8 0.1221282F 63Z22.I 3000 0. 1V7'.055E 71824,4 3100 -17950'..0 n06U0.9 •197019.6 0.2611631E 3200 3920239E 89815,5 3?00 •19633^.9 99204.4 2'*00 -205132.3 0.59i;91B3E 108855,4 3500 •21^-210. 0.929878flE 118760,6 •223568.4 0.146fc982E 1299^.4.0 -233205.9 0.2339159F 139331.7 i^§8 -243122.4 0.3701077r 150081.5 3800 -203317.*. 0.6iei231E 161043.5 3900 -263790.6 O.1O21050L 4000 -274541.5 REACTION 3NB4RAC = 2rJBB2*NBC 100 -10^199,3 O.nOU IE 39 -106100.2' 200 -102^30.0 0.17014 ll 39 -10i.yj^6. 1 300 -101509.8 0,170l4lir 39 -103570.0 cCO -10159^.,5 o.nounn 39 -iOi9'.3.6 300 -101719.7 O.nClfcUF 39 -10U061.3 600 -1022^.6.2 0,10OR33r 30 -97921.2 700 -10?:55.^ O.l6n05'.0r 33 -95522.4 f?00 -10ifc2'.. 1 0.25C0098E 29 -92i;66.6 900 -1060^*1.5 0.ie27.oo5r 26 , .-39^47.6 -107997,6 0.413 7.K-8r 24 -06771.2 -1102^'..5 . 0.9t0l493C 22 -'J3335.3 1?38 0.»7t2259t: 21 -79639.9 1200 -112695.5 . -75CB5.0 poo. -115P25.<. 0.3Ct3953r 20 -119Ce9.5 J9673:2F 19 -7U70.4 752990F 18 -i6996.2 1500 -12;>62*'.0 -62262.^ 1500 -12fc'-Q5.5 193757ir 18 -130651.0 StOO067r 17 -S7:6t;.9, 1700 -52t;l5.8 leoo -135117.9 26C1235r 17 -139fiP3.9 125fl2ClF 17 -46503*0 lOCO -l'.*.9&6.fl . 70524SUE 16 -40V3C.6 2000 -3'»690.4 -15030^*.9 '.fcfi3i.l5E 16 -2B''06.6 -155556.5 0,317t3Eir 16 -218 55.2 1188 -151699,9 o,24ViB;5r 16 -15CO6.0 -16:il3j,7 0.2Ce75';2r 16 -17tt57.0 • -7973.2 mi 0. li;9i. 132f^ 16 -6^2.7 2500 -1SU5£).0 -I3n066.2 o.ie3nj9E: i6 4"^*.7.4 2600 14797.3 2700 -195950.^ 0.1S7:J9iF 16 -203619.3 0.2011757r 16 22906.9 2? 00 . 31276.2 2100 -211572.5 0.22cC2S8«^ 10 •-219e09,0 0.26'*2913E: 16 39905.2 3000 ^.8793,0 3100 -223328.0 0. 32033';5F 16 -237128.A 0.'.010729F 16 579i.2,2 3230 67350.2 3300 -2^.6210.8 0.5l71219r 16 -255573,4 0.6e*.7077E 16 77tie.O 3'.00 0,929! 352F. 16 0 69M5.4 3500 0.i2dfi9fi2r 17 97132.5 1*788 o.ie2i..ne5r 17 • 107579.4 3flC0 118285.9 0.2632239F 17 129252.1 3900 -306574.5 0.3862i.5?F 17 4000 0.57579B6E 17 REACTION 3NB20546B203+22AL « 6NB82+nAL203 0.17CU11F 39 -13513C1.5 100 -lf.0(t225.2 -U20911.2 -1625005.7 0.170U11£ 39 200 39 -U59156.5 300 -1^.1(1225.2 0.17UU11F -UQ0766.2 ^•00 -13999&9.0 0.170UIIE -1516293.7 500 -137*.751.7 cuoum: II -1537252.7 600 -13'.'.651.2 0.17C1M1F -155a292i5 -1310853,7 o.noiciiF 700 39 -1577737.7 -127^.172.0 0.170U:iF -1595769.5 noo -1235129.5 0.17CU11F 900 5? .16U..95.2 1000 -1191.1^.9.7 o.i7ounr -162798*..5 llOO -1151555.7 0.I70U1 IE -I6*.22a3.0 1200 -110760*..0 0. 7CU11!: -1655622.5 1300 -1C62506.5 0. WOUilF -16676i;5.7 l^tOO -1016'.^0.1 0.17016 J IF 39 -167P309.2 1500 -96555*..6 0.170U11F -16clU005.5 1600 -921979.3 0. 1701611E -1696766.5 -873P26.2 -17C6353.2 1700 -C25193.7 0. J701*»]1E IflOO o.nouiiE -1710657.5 -776169.0 39 -1716202.2 1900 -726P29.6 0.17C1*.! IF 2000 0. 1701*.nF -1720631.5 2100 -6772*.5.0 -1723507.'7 -627630.6 o.noiciiE - 726116.0 2200 -577.5B9.7 II 23C0 CWOlfcUF 39 -1727252.2 2600 -527625.5 0.170I*.:1E -1727326,2 2500 -*.77635,6 0.i7Jl*.IlF 2600 -62766*..3 0.l70Ui IE II 27C0 -377750.5 0.9322t.73E 39 -327933.2 0.393;899E -1721157.2 2P00 -27e?*.6.0 39 -1716977,7 2900 0.6oei-*.i;6E 36 -1711737,7 3000 -226721.1 0.953:3:0E 31 -1793QB.3 0.66'>^^9o2E -1705638.0 3100 -130275.5 26 -1690079.2 3200 -6U09.7 o.*.5iii;*cr 21 -1609661.7 3300 -32012.9 0.799UJ7E 17 -16BC106.5 3t00 156Bd.n 0.26fll6'.*.t -1669653.2 3500 63*.7*.,6 0.1209536E II -1658063,0 3600 111122.*. 0.li;77U7E 0-6- -1665615.7 3700 159*.l6.2 0.n96l36E-003 -1631712.2 3flOO 205334.0 0.2706611E-0060 -1616952.0 3900 0.76*.9760r-09 -1601135.7 <»000 251860.8 0.30666O9E-n 0.17O1752C-13 REACTION N8205*2R203+11MG»2NBB2 + UMG0 O.WOUllf: 39 57^.433.7 100 -58t2?0,2 •5fi?61j6,7 -5972:0.7 0,170141 IE 39 200 39 •599270.7 300 -593829,6 O.WOKllF •to 7159.8 -577^61.0 17CU1 E aCO tl E •Ol'.lCO.O 500 -569216,0 17C1 I? •6203'.2.6 600 -5596^2,6 nouiiE 39 •b2 J02:J. 1 700 -5i.';06fl.2 1 ?0U11E 39 •63 1 177,1 flOO -5377 16.jb 17C1/.11E 39 •63 5636*2 900 -5257^9,3 170U11E 39 •6400:2.0 ICOO -5l32r.0,7 170141 IF 39 •6'. J7'«0. 1 1100 -50C4.J1.4 1701i.llE 39 •6470: 6.5 1200 -tfl7255.0 170li.llE 39 -649038.5 1300 -*.7'Jn2'..0 17C1411E 39 •652216.2 uoo -i.60192.3 170U11E 39 •65'«r^2.3 1500 -'.'.:J'*06,2 1701^11E 39 •665649.0 1600 -i.32505.2 170141 IE 39 •6567L'7.7 1700 -'.1R'..2'.,0 17Cl^r.F •6i>7330.0 1000 -i.0'.i.y3.1 1701*. IE It •657616.8 1900 -390*.39.5 0.170U IE 39 •657260.8 2000 -37i,3y7,2 o.nc-unr 39 •65t.5y6.'7 2100 -362350. 0.6t.lt.''.P^.E 30 -655^71.1 2200 •6539^2.2 -33^.'.'.5.8 0.^:^''703E 35 23:iO 32 -6519''0.7 2i.00 -3?C5^6.5 o.62ei.c6'.r -64'y526.7 -30(ia3!i.6 0.16270955 30 2500 27 -6<.66Q0.5 2600 -2'^31B3.9 0.69110e3E -6^. 3'i02. 3 -27?6^i0.P 0.45600C2E 25 27C0 23 -639692.3 2600 , -;6t)2-5. 1 0.'.'.M066E -635550.7 -25.'">/9.6 0.6:i657nE 21 -6309/7,7 2900 0.1191/^'»'.F 20 3C00 .-239ev'..l IP -625973.3 3100 -2269 jf).2 0.3U6u274E -62J537.7 -21^120.7 C.l^l^.flilE 1.7 -61^671.0 3200 -201509.7 0.*.2enH39E 15 3300 14 -600373.1 •3^00 -iaysi'3.2 0.22'.'5570E -601644.2 0.1-497C3E 13 -59'.4Gt».5 3500 -17b9'.7.8 0.112U337E 12 3600 -16^811.0 11 -536893,0 3700 o.io26;flor -378872.5 -152979.3 o.iicooi.3r 10 3300 09 -570<*20.1 3900 -129954.1 0.1363729E -561537.2 4000 -110772,2 0.1925072E §? 0.3113273E REACTION TA205+^B-f5C = 2TAB2+5CO 251802.2 100 234063.3 O.OCOOOOOF CO 200 21'-284.4 O.OOO^UUyE i-'O 255776. 1' 300 1932P2.2 0.00C3000E CO 256707,5 256763.1 400 172116.2 o.oooyoosE 00 500 150992,1 0.Ci;0t;00OF 00 256?7i.2 600 129975.3 O.OCOU-JO:E I'C 251:691.4 700 109092.4 0.03U279E-34 25'* 7 70. 3 800 8S355.8 0.7C49225E-24 25364'..0 900 67771,8 0.3412697F-16 252329.8 1000 47343.a 0.443'J572E-10 25-Tnj7,9 1100 27073.5 0.414 /';i /F-C5 249 1 7^.9 1200 6962.0 0.53eCi.47E-01 2^'7345. 2 -12990.2 C.153166DF 03 246361.7 ini -32702.9 0.132O2:2E 06 243196.7 1500 -52416.0 C.4j7y!t5/E OU 24JUU I.O 1600 -7 869.3 0.668V276E 10 230'.O8. 1 0.53929Q2E 12 235776.6 1700 -9 203.0 232907.9 1900 -110357.4 0.2553I6HF 14 -129352.6 0.7720y4HE 15 230042.6 I'JOO 0.1595CBr.F 17 226941.2 2000 -14tilU8.5 10 223694,I 2100 -16t^?65;6 0.2377*.59E o.:672-;nF 19 2 20271.5 2200 -1U'J303.S 20 216703.6 2300 -2C3743.4 C.;351772E 21:900.7 2'.00 -22194*..5 0.16697e9F 21 2C9102.9 2500 -23*i997,2 0.9ei6905F 21 205C70.5 2600 -257p71.fl 0.4U114311E 22 20U003.4 2700 -271.'^98.2 0.2C*;6123E 23 196541.9 2600 -2931h6,0 0.7e72540E 23 19 2U46.9 2900 -310677,5 0.26:VC4?r 24 18 7395.7 -327830.5 0.797B343E 2^ lfl2591.2 -34/.926.0 C.2145t60E 25 i?88 0.53535tiF 25 17 ;632.5 -36int3.8 172519.0 -371:644.5 0.1233n94F 26 0.264L246F 26 167262.9 -39S-267,0 161832.0 -411733,9 0.53C75CI,E 26 0.1002?0'.F 27 156267.0 3600 -420043.0 150526.1 3700 -444195.1 0.179014*.E 27 -460190.2 0.3037342r 27 144645.3 3800 0.4915106E 27 138608.5 3900 -476028.6 132417.9 4000 -491710.1 0.7612783E 27 REACTION TA205+26203+11C « 2TAB2+IICO 100 659693.1 o.ooooooor 00 697760.3 200 615138.2 0.U(J003U0[^ 00 706*;67.6 300 56R769.3 O.OCwOOOO^ CO 709132.1 *.00 5217U5.3 o.oeouocoF 00 710305.2 711C5V,6 500 *.76^63.9 O.CODOOfiOF 00 600 •627203.5 711712.5 700 . 379731.5 O.UGOU'JtOR OC 712600.6 7l3215i 800 332152.7 o.oocuofor 00 900 286664,2 7161 70, 1000 236660.*. 7l5:yij.2 1100 18873*..6 o.cccocoor CO 7 16612.7 1200 16R680.5 tJ.o(,^uji.jf to 718123.7 G.301922ir-37 719038.0 1300 92692.1 72176C.6 1600 6*. 16 3,9 0.?209710r-25 1500 -6 309.0 0.27660?7r-15 723895.0 0.12o3716r-C6 726263,8 1600 -52<:31.6 720a09.2 1700 -101707,3 o.626eic6r 01 731592.6 1800 -1506'.0,5 0.1715Z^Qr C8 734'.»95.3 1900 -199734,2 0.12;0691[ 16 737010.5 2000 -266991.9 0.1S:99756r 19 761262.7 2100 -29E616.3 0.97307tf9r 23 7*.6V20.7 2200 -3*.PC.09,8 0.16767t6r 2305 38 76BP17.0 2300 -397775.1 .11B7933E 32 752920.2 2600 -'.67 716,2 .39C7U67E 39 8 39 75726;;.5 2500 -697829.2 0.659U0»-3F 761 i'20. 3 2600 -560122.2 0. 17CJ161 If 39 2700 -596596,/ 0,l7C;l6lir 39 76&&U2.0 2800 -669268.5 0. i7oi6ur 39 7 71»,C7.7 39 776l'37.6 2900 -700006,6 o.i7oi6iir 782291.6 3000 -751105.6 0.1701611F 707970.7 3100 -802311.8 0.1701611F 793fi76.3 3200 -853706,8 0.170l6lir 39 600002.7 3300 -905285.0 0.l70l6nF 39 806356".0 3600 -957C56.2 0,1701611E 39 812936,3 3500 . -1009016.3 0,170 6lir-39 619737.7 3600 -slR61168.0 0.1701611F-39 826766,2 3700. -1113511.5 0.1701611F 39 83402C.1 3800 -U66068.2 0.170l61ir 39 841699,2 3900 -1218778.7 0,170l6lir 39 649203.6 UOOO -1271703.7 0,1701611F 39 0,1701411E 39 0il701*>llF 39 REACTION TA205tB4C-t4C »2TAB2t5CO 100 245651.5 O.OCOOOOOf- 00 260506.5 200 227464,7 O.OOOOOOOE 00 267969.0 300 206578.7 o.oocuouur 00 270536.1 400 165022,9 O.OCUUOCOc CO 272002.5 500 1631^4,2 O.CCLtfCui? to 273127.3 600 141C49.9 2/6 166.0 700 118791.3 o,ouuwOuor Ob 275220.8 flOO 96356.0 0.7816939^-37 276352.0 9C0 73786,2 0,45U2526E-26 277;.87,7 1000 51067.1? 0. 1 13C906,'r-17 278966.0 1100 20209.0 o,6BC09ve:-ii 2BC63C.5 5203.0 0.2i66567f:-05 282C72.8 H88 -17935.2 0.1126642^ 00 283e5'..l -41221.3 0.1059ei9£ 06 205786.3 14C0 -64650.8 1500 0.276b:66F. 07 2078.72.2 -88224.7 0.2t615?2E 10 290116,0 \To -11 lSt3.** 0.11'.2075R 292513.0 1800 -135E08.0 0.251C616F 295070.6 -159019.1 297707.8 1900 -182977.4 0.3155092E 17 2000 -209283.6 0.2672609=: 19 300665.3 2100 -232738.3 0. 1305.0.72^ 21 3^3706.0 2200 1361 374F 2'. 306904,0 -2573a2.2, 0.6flq7293'2933777E; 25 23CO -262095.8 310266.0 2tOO 5051166?: 26 313790.3 2500 -306999.5 71 386^^3^ 27 -332C54.0 04;3163E; 20 3176 77,2 2600 -357259.8 321327.0 •27CO U6l26U0f: 29 325339.8 2000 -382617.1 7622995^ 30 -403126.6 5960376C 31 329515,9 2900 •-43379fi.'. 333855.5 3000 616P6?4C 32 338358.5 3100 -659603.I 263t.360r 33 -605571.0 1521955F 34 343C25.2 3200 -511692.4 367855,7 3300 -537067.6 o,noe7g5or 34 352n50,l 3^.00 -566397.0 0.?Sn55C7F 35 358008.4. 3500 -59C980.7 0.1833128r 36 363330.8 3600 -617719.2 0.7915262F 36 360817.2 3700 -644612.6 0.3225045^ 37 374467.8 -671661.1 0.1245&V7C 38 380202.6 -698865.1 0.4560363? 38 386261.7 i?8§ 0.1609171E 39 4000 392405.0 REACTION 2TA*B4C = 2TAB2-#C O.noitllE 39 -80475.0 ICC -87014,6 -B7O43.0 -85932.7 0. TOl^-llE 39 200 0. 701ti:E 39 -86172.3 300 -B5'»43.0 -84673.5 -fl5«tl9.6 0.170U11E 29 400 0.3?5427JE 30 -0;'943.9 500 -85801.0 -80999.1 •-96550,8 0,35C4393E 32 600 0.2399027E 20 -70P2't.5 700 -B7£4t»,^ -76425.3 -69066.0 O,22>0150c 25 eoo 0.1154P23E 23 -73601.5 -9O0O1.3 -70953.2 900 -92P40.fl 0.20C5625F 21 0.ti335l7/E 19 -670tJ0.4 ICOO -95176.5 -645C3.1 1100 -97R01.8 0.6646419E 18 0.e73U3e5E 17 -61C61.4 -100711,2 -57315.2 -103<'fJ0.4 0.169'.697E 17 H§8 0.*.i90090F 16 -5334*,.7 -107365.0 -i.91'.9.6 1400 -111102.0 p.l5301i.9F 16 0,64C;9fl33E 15 -4t730,2 500 -115108.2 -aOCU6.3 600 -119301.0 0.3186635E 15 O.1023H5"jr 15 -35210.1 700 -123918.0 -30125.4 fiOO -12B717.1 0,11P523'JE 15 O.fl520622E 14 -2^800.3 900 -133776.5 -19266.8 2000 -13^;C94.5 0.6696795E 14 0.5605?t..ir 14 -135C0.9 2100 -14^.669.4 -7510.5 2200 -15C.500.0 0.5163?63E 14 0.*.973562F 14 -1295.8 2300 -156504,9 51'«3.2 2t00 -162922.7 0.5y45P37E U 0.5359flC3F 14 1 1006.0 in°o -169512.7 I669t.7 2700 -176353.5 0.5930t31E 14 •0.6005293E 14. 25807.0 2800 -103'*^4.4 33143.8 2900 -190704.3 O.DO6B270C 14 0.985i359(.E U 40705.0 2000 -190372.6 *»at.90.5 3100 -2062C0.5 0.123i.923F 15 0.15e5716F- 15 56500.5 3200' -2U291.1 64734.8 3300 -222619,8 0,200092J£ 15 0.27e5333E 15 7 3193,6 3400 •-23n9*..l 01Q76.7 3500. -2^0013.2 0,379C107E 15 C,5259fl49£ 15 90784.3 3600 -2^9076.7 99916.3 3700 -250384.0 0.7399150E 15 0.1055433E 16 109272.7 3800 -267934.5 U8853*4 3900 -277727.8 0«1524d93E 16 4000 REACTION 3TA+B4C :i 2TA02tTAC -123324,3 -121587.4 0.170-1411E 39 100 Q.1701411E 39 -122120,7 -120312.1 0.170U11E 39 -12C770.9 0.170U11E 39 -119206.6 538 -119691.7 -117*-K. 1 -U9561.5 0.170U11E 39 400 O.WUUllF 39 -115380,8 -119852.9 -113120.0 500 -120527.0 0.94325yon 3(1 600 0.i*a0£637c 3*. -110633.2 -121550.H -107901,4 700 -122930,6 0.1913790(:- 31 600 0.49'.04r7^ 28 •-104933.0 -124629.3 -101727.9 900 -126644,9 000 0.4353893=- 26 -90285.0 100 .12!1969.3 0.957J129E 24 -9<.606.e 200 -131596.0 0.4246528E 23 -9O69J.0 -134519,4 0.3265963^ 22 -86537.6 ,400 0.3895313E 21 -02147.3 ,5C0 -137735.0 -77519.9 -141238,0 0.662t'263^ 20 1600 0.161C3*.2F 20 -726b'j.2 1700 -145027.4 -67553.4 -U9C97.9 0<*.3Q6rG'-.E 19 0.1560706? 19 -1534it7, 5 -6221'*.3 -150074.0 0.&6001U4E 16 2000 0.323i.5!3'^ 18 -5b63U«0 21C0 -1 62975.3 • -50B2'».5 -166149.5- -i.i.7 73.7 -173694,9 0.76*»10e3E 17 -30485.7 i!88 -31960,4 2400 -179310.0 0.5t-H253ie 17 -185293.3 •0.4;r5170lE 17 -25197,0 2500 -18197.9 2600 -191643.5 0.3893939^ 17 0. 3532 13*.^ 17 -lov60.e 2700 -190059.5 -34B6.4 2800 -20^P40.2 C.33760/3^ 17 -211884.6 0.3302029^ 17. 4226.1 2900 1217*..1 3000 -219191.6 0.353^398! 17 -1:26760.5 0.3e37373E 17- 2U360.3 -23*-590.5 0.4313C92E 17 2U703.8 -2(>2680.6 0.5002702E 17 3744^4,6 1288 -2 51C30.3 0.5971347E 17 46342.7 3500 -259630.8 0.7316806E 17 35470.0 3600. -268505.6 0,9183143^ 17 64850.7 3700 -277630.U 0.1178239^ 18 . 74460.6 -287011.4 3noo 0.1542601E 18 84307.9 -296649.4 0.2057943E 18 94392*4 3900 -306543.3 4000 -316692.6 REACTION 3TA205+6B203+22AL«6TAD2+11AL203 -1296183.7 100 •135C657.7 0.1701411E 39 -1366922.5 200 •1372391.7 0.1701411F 39 -1605658.5 300 •13fc6?25.7 O.i70l4llf: 39 -1435296.7 -1348502.0 0.1701411E 39 600 O.WOUlir 39 -1661139,2 500 .1323751.2 - 14 6 6 S 6 9, 7 •1296061,5 O.noUUE 39 -1506203,2 •1260556,7 C,l7y]611E 39 -1526634,0 ^88 •1224068.0 C,1701411C 39 -1545629,2 800 .lie5119.-5 0.1701411^ 39 -1563300.2 900 -1166117,0. 0,17U16UE 39 -1560110.5 1000 .1101376.2 CI 701/. HE 39 -1595931.5 1100 C.1701411F 39 •lC57l4fl.7 0.17016 HE 39 -1610772.2 1200 •:i0ll64l,5 -1626666,2 1300 -965027.6 C.170161 E 39 -1637(,26,2 1400 -917652.6 0. 170141 F -1669665,5 1500 -H69063.6 0.170l6lir ll -1660799.0 16C0 -8J9909.1 0.1701411F 39 -1671039,2 1700 -7?0165.5 0,1701411E 39 -168C365.5 lOCO -719?37.8 C. 1701'-HE 29 -160t!611,2 1900 -669060.6 O.nOUMF )9 -1696370.7 2000 -617896.3 0.1701'.11F 19 -1703067.0 2100 0.170U11F 39 -566369.1 - 700842.7 hoo -516367.8 0. 70U11E 39 -662533.6 0, 70li.llC 39 - 713760,2 2300 0.777319CF 36 -1717801,5 2600 -610313.3 -1720967.7 2500 -357968.1 0,1276in2F 31 -305'.7e.3 0.55n 293E 25 -1723260,5 26C0 0,56BC697r 20 -1726680,7 2700 -252039,5 -1725229,7 2inO -200364,8 0.1266569F 16 -167705.5 o.5';2:2i6E 11 -17265C8.0 29CO 07 -1723716.7 30?0 -95233.8 C.522212:E - -1721656,2 31C0 -62731.1 0,831973tE 03 9691.6 -171H727.2 32;io 0.2279l6£f: CO -1716930.2 62013,4 0.1v267Q6r-c3 -1710265.7 VM 116211.1 0. 73139Gir."07 -1706736.0 3500 166261.9 0.7P56396F-10 -1690335,2 3600 218168.6 0.1279?2Cr-12 -1691070.2 3700 269B50.4 0.2957765r-15 -1602938.7 3800 321369.1 0,95B3fl59F-18 -167394U5 3900 372629.9 0.4251184E-20 4000 REACTION TA205+28203+11MG *2TAB2+UMG0 -556061.0 -566374.3 0.1701411F 100 0.170141 IE -5716tj0.6 200 -569590.7 C.1701411E -501372.1 300 -566696,3 0.1701611E -5R9336.6 400 0. 701611E -596362.2 500 -560305,2 0. 701611P -607704.8 600. -552216,7 0.1701611? -60u663.1 700 -5'.2772,8 -6 *'ii75.8 SCO -532299,3 0. i7pr -619056.0 -521015.5 C. 1701411E 39 -^23623.6 -509079.6 0.17U1611E 39 -627790.6 -496611.4 39 -631566.0 0.1701611E -636955.2 -463705.1 17C1611E 39 -470636.0 39 -637962.3 1701611E -640590.7 nil -656869.3 170161 IF. 39 -443055.1 39 -642862,2 1500 170141 IE -666719.0 1600 -429039,2 170161 IE 39 -4l6Bt0.J 39 -646222.1 700 17016 IE -667352.6 800 -400552.1 1701611E 59 900 -3Qt»166.1 39 -648111.7 0.170141.1F -640499.7 2000 -3 71662.9 0.6707561F. 36 ?100 -357131.6- 0.4007157E 33 -64ti517,3 2200 -362571.6 n.6323f»32E 30 -660165. 1 2300 -32fl0O1.5 0.1715963E 28 -667463.3 2400 -313639.2 0.7527ni6E 25 -646352,3 2500 -298899.0 0.5063012E 23 -666892. 5 -20^.398.6 0.69'72655E 21 -643063.8 -269967.0 C.693330flF 19 -66CP06,7 2900 -255560,4 0.131631 IE IB -6333'J1.3 2900 -261267,5 0.329501JE 16 -635367.8 3000 -227019.7 0. K.t5765E V -632066.2 3100 -212nB6.4 0.6367675E 3 -623396.7 3200 - 9iiE-57.3 0.2192962F -626359.3 3200 - fl696C.2 0. 1363R63E H -619956,3 3600 -171163.9 0.9d6c691E -615181,7 3500 -157675.3 0.0512e66E It -610061,5 -163941,6 0,8569978E 07 -6U6533.6 l?38 •-13C549,3 0,993631BE 06 -117305.0 0.1313370E -59U65a.3 3800 -104216,6 06 -592415.8 3900 -91203.5 0.1961029E 05 4000 -70517.0 -565605.8 REACTION 2B2 03+7C B4 C + 6C0 448418.1 417123.5 O.OOOOOUO^ 00 100 O.OOOtOOO? CO 44.?625.6 200 3C839-;.l 43U520.1 362190.8 O.OOCCOOOE 00 300 O.UOOUOOvF 00 43^<<66.6 too 337353.8 43U138.I 313569,4 O.OOOOOOOF 00 500 O.OOODOOCF 00 425425.6 290691.p 420282. 600 268636.1 O.OOOOCOCE CO 700 247340.9 O.OuUuOOtF 00 4 14605.1 eoo 226791.0 O.vOOyCOCJE 00 40C620.B 900 206P33.9 O.OUUuOui^E 00 402001,6 1000 1077,54,9 0.4727775E-37 395062.6 1100 169236.2 0. 144/,76tE-30 387560.6 1200 151363.1 0.3456351E-25 379573,2 1300 134123.2 0. 11223055-20 371098,8 1400 117506.4 0.74UioahE-17 362136.1 1500 101503.3 0.134U161C-13 352684.4 1^00 B6106.2 0.039065: 0,1701411E 39 -252254.0 100 -257278.5 -260037.4 200 -259822.3 0, 1701411E 39 0,1701411E 39 -265300,0 300 -257045.3 -270292.3 400 0,17014115 39 -253542,5 39 -27646'..3 500 -2'-6752.3 0,17014 nr -2aC966.3 600 39 -242911.2 0.170141 1| 39 -206F62.2 700 -236108.4 0.1701411^ -293164,5 BOO 39 -223431.5 0.17014111 39 -299950.6 -219935;B. 0,17014 IE 39 -307171.8 loSo -210662.4. 0,170U IE 39 -3U854.6 1100 -200643. 0,1701411£ 35 -323003.5 1200 -189904.4 0.404205fcE 31 -331621.6 1300 -173f.66.6 0,1048478E 26 -340711.4 1400 -166347,5 0,9621fc57E 23 -35027^..3 1500 -153562,1 0.2i.3fl390£ 20 -360311.0 -140123.2 0,lt:C3l5E -370824,5 1600 -126042.0 7 1700 0.163*.?07F I* -381013.5 -111328.3 0.3349372E 12 -3y 327'y,l -•;5';9o.o 0.1116706? -405221.6 -80037.2 09 1158 0.5630n4tE 07 -4 1764 2. 1 2000 -63474.5 0,^.07i53?E -4630.9,0 05 -43:54c,-3 2100 0,4CC';346E 03 -^.4 3916.6 -29546.2 51772W:E -457771.2 -10191.4 01 1188 C'.84C1CE 00 -472104.3 6750.5 1716237E -486915.0 1^88 2B275.4 4106?SCF-02 -5C2*;C'6.6 *.B379.3 1*:C6?9; E-03 -617976,0 2600 6925?.4 2700 4C4i92rE-y5 -53''224,3 X 90309.2 -55C951.3 2600 12128.6 . 15492'.7E-06 2900 C.670b7bSF-0lJ -66t;i58.3 34513,6 -686844.2 3000 157461.5 C.3246136?-29 3100 O. 1736'vR7F-10 -604009.2 160969.3 -622653.5 3200 205035.0 O.Ul':306F-ll 3300 0.6497531E-13 -641777,1 229656.1 -661360,2 3400 254830.7 0.4i7';347E-l4 3500 0.3316926F-15 -68 1462.7 260556.2 -702024.6 3600 306931.1 0.2621343E-16 3700 0.2202117E-17 -723065.8 333653.3 -744586.8 3000 361021.3 0,1957176E-18 3900 .0.1832931E-19 4000 4BCL3"^4M2"*CH4'B4C+12HCL REACTION 122836.1 o.oco;30uuE 00 120230.2 110388.0 O.vuOvO'JiiF 00 117309.5 99892.1 O.UbO.OwvE 88850.0 CO 1143:2.1 0,t;.L'jiu'-E vO 111223.8 B 79313.0 0.5ie434;iE-31 400 71532.8 108338.7 0.5334226F-23 1053t:i.7 500 63855. ,15Vl07^.t-l7 5667'5.6' . O 102464.2 0.2265531E-13 9 9596.1 ^88 49917,2 0.266250;r-10 63521.7 96786.5 0.668?70>E-Oe 9 606 4." 188 37462,4 0,5l25nQlE-O6 31661,2 91377. 0.17627CJr-04 88795. 1?88 • 26086.6 0.323n36E-D3 20751,0 06306 1200 0.3664092t;-C2 039 15 15610,9 0.2bC572 -0l 1400 10665,4 '^g 01634 1500 C,15';3631E 00 79..09. 5835,8 00 1600 1165.3 o.7op.nHOi 77630.2 1700 01 75523.6 -3331.4 0.237518JE 01 1300 -7C10.3 C.794C;50yE 73757,8 02 7 2 > 1. 0 1900 0.21369(-2f; 02 2000 0.511919'.F 03 70601.2 2100 0,H14365F 03 69386.5 2200 C.2237 ?E9!^ 03 6(1264.0 0.6192612E 67324.1 2300 -237B1.0 C3 2600 0,74J526dE 06 66572,5 2500 -32805.5 0.126376?c 66010,0 -36795.2 0, 2-u;;224E J6 65668.6 !'78§ -t.J759.7 0,3lO19C6F 04 • 65532.3 -44707,5 0.66504ti5F 04 6 5617.2 C6 -40666.3 C,68U76[:6r 65931.1 1188 C.97193ri,F 3000 -52534.1 66682.2 3100 -56529,9 0.1359936r It 67279.5 -60637,3 0.197C569E; 05 60227.0 3200 0*25354P2F 3300 -66666,9 05 69630.4 0.3396t,29F 05 71218.1 3600 -6B''76,2 0.44972;.7E 73076.9 3500 -725U.1 05 0.5906fllOE 05 75217.0 3600 -76599,6 .77023-:>3f: 05 3700 0 77652.1 -80730.6 0.9985159.^ 05 80300.5 3800 -84915.5 .1288430E 3900 0 06 4000 -89160.7 -93471.0 REACTION <.BCL3+8H2^'CC4j=B4C-+l6MCL 0,O0^.U0UOF iJO 53947,2 100 34714,8 O.2313113E-10 49527.2 200 17046,0 0,'.Cw63inE-0l 66336.5 300 1916.8 0,1767354E 07 39064,2 400 -11627.4 0.1795120: 11 33855.2 500 • -23665.6 28753.9 600 o.35i';9y6E ?3va5.i 700 -36626.7 0.03726fiOE \l 18943.7 600 -66559.4 0,57^9936C 15 14250.3 900 -53990.4 0.ie39*,62F 16 -62623.9 0. 360tO57G 97C3.2 -71162.5 0.51'J'-6''.DF }^ 53C6. 5 -79012.9 0.:»7693V5r 16 1055.6 -E660y.5 0.55''5UJ4E 16 -3062.5 li38 -93617.7 0.4e75212F 16 -6909.2 1400 -100636.2 0. 39623'*OC 16 -10706,0 500 -1C6977.D 0.3C27073F 16 - 6626.6 600 -113270,7 0.22'.55'-5E 16 -17916.2 700 -119340.9 0.l6273tl2F 16 -21253.1 IflOO -125210.0 0.1162n'.2r 16 -24637.0 1900 16 -130097,9 0.e265725r -27667.7 2000 . -136621.8 0.50315O2F 15 2100 -161798.2 0.6121)126? 15 -30365,1 2200 -147041,1 0.293:O66E 15 -33C69.0 2300 -152163.6 0.2C9:>756r 15 -35639.5 2400 -157177.3 0.1500479^ 15 -3i;C56.5 2500 -162093,8 0.1C96nJ6F 15 -40319.9 -166922.5 O.0IJ1M8-9E 15 -62629.6 -171672.9 0.5931097E 14 -66335.6 !?88 14 -176354,1 0.6621144E -66108.0 2800 1ft -67U36.5 2900 -180973,4 0.3366e72F -165533.3 0.2551522E -69331.3 3000 -50672.6 31C0 -190U56.0 0.1966e7nE it 3200 -196533,0 0.1532163E 14 -51659.6 3300 -198975.2 0.i:C595.*E 4 -52092.9 3600 • -203308,2 0,95yD19OF ,4 -53772.4 3500 -207777.6 0.7704259E 13 -54490. 1 3600 -212166,6 0.6251177E 13 -55069.9 -216505.8 0,5121991E -;>5667.8 3700 0.4237105r 13 3800 -220853.8 13 -55751.8 3900 -225196.7 0.3538060E 13 -229538.7 -55862.0 4000 13 -55818.2 REACTION 4BCL3t6H2+C«B4C+ i2HCL 105060.5 100 94954.8 O.UCOOOOOE 00 200 84993.1 o.oouoouor 00 300 76740.7 o.i;cu-^ocor 00 0.7316739r-30 95609.0. 400 69756.7 92C-22.1 500 63699.7 0.l362CG6r;-t7 5313^c2r-^l 0t;45 2.0 600 52372,3 84990.9 700 53633.7 17577i,3r-16 3l74324r-13 01b72.7 BOO 49301.6 7 04 79.2 900 45538.9 . B6155V2E-11 6397347r-0V 75421.6 1000 42043.5 . 72502.2 1100 38048.1 10925.-13r-07 285495flr-06 69722,2 1200 35912.5 67082.8 1300 33203.0 2599915r-05 l6O7090r-O4 6^59''.6 1400 30691.4 62220.1 1500 28353.6 7352!lV2r-04 0.26515^2F-03 60013.8 1600 26169.1 57941,8 1700 2^117.0 0.79Jl674r-03 C.2C101C3i:-'J2 56C12.6 1800 22103.7 54226.1 1900 23353.6 o.^5t.37y7r-:2 52582.6 2000 10614,2 0.922Clt0r-C^ 51082,2 2100 10953,1 0,171o432f-01 49725.0 53 60.4 O.29V292ir-0 46511.X 3326.1 C.43467i4r-0 2341,5 4 74 4 0.5 10«390.7 o!lli3459^ 00 46513.3 nil 9490.0 0.15/I55ftr 00 45729.6 2600 0100.9 0.22n4l/.4r. 00 45Cfi9.3 2700 6748,9 0.297lO95r 00 44U92 2900 5403.6 0.3913:67F CO 44239 2900 ^C6B.7 o.5:5r-f'2r co 44029 2738.C o.64;,«;96:r: 00 43'^63 1407..0 0.0013<:05r 00 44C41 ^?88 44262 3200 71.8 0.9BV0/I2r 00 3300 -1272.3 0.1207345r 01 44627 3400 -2629.2 O.U5973nF CI 4 513 5 3300 -4002.9 0.1750472r 01 45/07.7 3600 -5396.6 0.2OB4273r 01 46583.5 ; 700 -6013,0 0.24667ulE 01 47523.0 : eoo -B257.5 0.2904105r 01 48606.2 3900 -9730.5 0.3403708E 01 49033.1 4000 REACTION '•Q+C = B'* C -10072.2 -12600.8 0.35S209:F 20 100 0.4483054E 15 -15307.5 -n'.oo. I 0.492345JE 10 -13801.7 f8§ -13296.6 0.15I52JIE 08 -13709.7 -1313i».3 0.4926'ji3E 06 -13462.6 500 -13017,a 0.5261?67F 05 -1320**.0 600 -12953.5 0,109'.124e C5 -12995.6 700 -12929.2 0. 342 19: 04 - rccu.u eoo -12929,5 C.13935(;3l-: 04 - ,2f:JH.4 900 -129*. 0-. 1 0.67e4lllF C3 -12917. 1 1000 -129C8.2 0.3?41?.06F 03 -13110.6 1100 -129^2.9 0.225t7ytiE 03 -13423.2 1200 -129U.8 0.1453790E 03 -1 385 '.9 1300 -12055.6 0.5^1^651.^F 02 -11/. 17.0 1^.00 -12758.3 o.t)9':7n5Tr C2 -r^ioi .9 1500 -12616.7 C.4991327E 02 -15914.0 600 -12425.3 0.3fr'-'M'f.'.F 02 -16654,0 700 -12179,1 -11873,9 0.277L3bJE C2 -17922.6 1900 -115C5.B 0.2U-9a30F 0.-! -19120.5 2000 -11071.3 0.1622785F 02 -2y'.4n. 1 2100 -10567.1 0.12tCU35F. \Z -219C5.7 2200 -9990.5 c.9nti;3f'E 01 -2?.'.?3.7 2300 -9333.7 0.77:5154E ui -2'.212.2 2C0O -8609.4 O.t.0e77fc6£ CJ -27061.5 2500 -780C.4 0.4811H<.5F 01 -29041.8 2600 -6909.4 0.3U11C45F 01 -31153.2 2700 . -5934.(1 C.3C24£.c3f^ 01 -333v5.a 2800 -fch74,7 c.:4i.2p«-'.r ui -3'j7i;9.7 2900 -2727.5 0.19]:.21iJE 01 -31*^75.0 3000 -2491.7 0.15i9^i.3r 01 -4;;5»11.0 3100 -1165.7 c.i2:f.4&bi: 01 -43'->S0.1 -46500,1 3200 251.5 C.96U943r: CO 3300 1761.6 -4 96U.e 0.76429b7F 00 -5.'7 7 5.;: S^-OO 3365.3 0.607<.p(.iC CO 350C 5064,4 -56070.3 0.4e259t6C 00 -59497.3 3600 6B59,3 0.383122:E CO 3700 0751.2 -63056.0 0.303y353E 00 . -66746.7 0.24C9246E CO -70569.2 ?588 0.19C01C2E CO i:>oid.i -74523.6 4000 0.15099&0E CO (Lxxxviii) A P P B N D I X XII COMPUTER PROGRA'-IrlE FOR GRAPH PLOTTING PAGE 1 // JOfJ LC!' CART SPETC CA-^T AVAIL PHY^CIIVE UUO'J 1/1^U(> ^'v'jJ 0021 V2 ^'09 ACTUAL I6f; CGNFKi 16< «L IST SCu:;CE o'^r.c-'V.v L-'J Ar-:u2.35) • 25 '>:ftUt2»3}.'; A^»Y.-:AX.Y -I'l 3 F; -t* AT ( ?="i:;.31 '••f'^-(2.:;MX( I ) . t») I Y t J ) » jrl •'•I 1 6 FO' •• AT t 10.-r.3) - I '.oXI 1 ) 5 pC'--iT(lfr=L.:) C'^LL f f'LOT I 1 f X ( 11 (Y (1 n IF lL-:.)'*i»»'jUiE»0 ^.5 or 10 Irli^-l lO.CaL iCFrM(5..M n .Yt r I I235..0. » C'LL F-LOT 1-2. XII).Yd)) Do i"! 20 CALL FPLOrKii -M I I iY( I ) ) CALL rl'LOTdtX-'AXtYV^A) LoL^i lF[L-*)i.C»30t3'J '.C- r.'^ ~0 25 u<^C Fn5 ST I//.' f^LCAiE C'iA'i^r. Pf.:!') 3: CALL SCrO?t7.SCf)»»5C^'Y.D.,0.1 . , « . CALL tcyA'?(X':l->2o/5CFXtY' !.\+4/0CFY»0» 1 • C.2 »C.» CaLL EXIT IOCS CO'vf.^' 0 VA-UABLES A26 PaCG.^A'-: 372 E'-f: OF COiPiLATiON (xc) APPENDIX IV •• • , COMPUTER PROGRA:S;S for CAICULATIOiT C3F FRACTIONAL VOLUMI': CHANGS FOR GOJ-P/ERSION OF MSTALS TO B0RIDS3 Mn) G/iRBIDBo Alg) THEIR SUBSEOUEI-TT COif/ERSION TO OXIDSS. FRACTION VOLUME CHANGE TA3LE3 FOR B OR IDES AND CJLRBIDES PAGE // JOB LOG DRIVE CART SPEC CART AVAIL PHY OSIVE 0000 &006 0006 0000 0312 0001 0002. V2 y,09 ACTUAL 16IC • CONFIG 16IC // FOR •LIST SOURCE P^OG^Av • ONE WOI^O i.-TFGFRS SliQPCuriNE OXI0E( R.VrCOI OI^.ENSION NAwr (9.3> .CLASO(9.3) .A01(91 lOOK?) iCOK #1 1 .fliKOi »D0(9i .cm-;) ,Mjoi9i ,rM0t9i COM^O*; l*fiO .!jO.CO».'.01tbOl,COl.'iUO.f:AO.C.NAN'E.CLA:iO RM AOt I 1 •i)0( 1 1 •C0( U»5fi?T( 1,0-C0S(A01( i ) 1 •-Z-COS*1 ( 11 l»»:-COS(CO IK I t ) ' •2*2.J'COS( AOK 1 ) » -COSIbOl I I ) )»C051CC.l ( I ) ) ) l/U:U0( I I'NAOt I) ) W7! rrt ?• 121 M^.A^Tt I • Jl • J*J .3» •VFCO#lCcASO( I » J J t J»l • 3) t AO 11) 121 FOR VAT (C)yXt3ft2.2X«H7.Ji«2Xi3A*.»8XtF7,^) VfJ I IE 23)110(1) 123 r'nRV.Al ( lObXir?.*.) W9l7F(3il23)C0(I) • rE.^lr OTII3.' . FEATURES SUPPCr^TEO 0\'E WORD r-cTCGERS CO'^E PEOUIftfMEMTS FOR OXIOF COvMOfJ 212 VARIABLES 26 PROGRAM. 25*. RELATIVE ENTRY POIfJT ADDRESS IS 002F (HEX) ,END OF COMPILATION• .// DUO cllflO 000^''' 0^\D8S^°'^39. D8 CNT 0013 PAGE CHAUDHf^Y 1 VAQ 9)»80t9) .C0{9).NU0C9).NA0(9I.P^itOI.CCll^ 99 ni^u^k'^loE',n,:f'itc,^^^ •2X. 'C^v«lT,lA?T. • t2X t 'LATT.Cn.'.ST, * »2X» 'OXIDE ' »2X »•FR AC . VOL. •YST.LATT. ••|2X , 'L^TT.CONST. ' 1 9P F0HrMT(9y . AOH ! t -ATI 1 I 1 •a. !i3/ia0.0 3^1 ( I mt-oi ( 11 l'O/l-J0*0 I'.O COK I-COM 1 1 *3. I'.3/iaO.O 202 F(»RVATt3Fi,,i».3Ft.l.I2.M.3A2.3A^) 3 OFACfP.lO^tAfiiBBfCniAr^l.bOl.CBlfNUBtNABvfNAMCQtJIfJ-USt •(CLASfMj) l.J»! O) AF;:'=Al:l«3.)'-3/lfiO.O fiMBl^ill'-J.l'O/U-O.C CLJi«ctn»3.ii.3/iao.c 106 FORMAT (2iU I "1 P- AMt£lM"CM-SC^^T( l.Q-CuSM"l I '•COSfA'^;! »-COS(HMl) •C0.110**JI-COS(CMl X •) • COS (c^ 1) *2.0 • COS(Av n • COS( BN:i I • COSt CVi) I /NUM o O - (AR^eS-CB'^SMTTC l.O-CUSiABU-COS(Ani)-COS(EBl»«COSOQl»-COSlC • ei)«cc:s(CBn * 2,i;*ccs(ABiccos(0tiH-cos{C3ii M/fNuo-NAG* VFCro^-AcInS&c.(l)'co.n-scRTa.o.cDS(Aoitn)K^^D a (0-?)/P ^ Kri(^oitit)-cosic:Ji(i»i-ccsicoi(i))*2.e»cosiAOi(ii»»co• COSliJO: K 11 I •CO is // XEO CKY^I'LATT. LATT.CONST. LATT.CONST CRJgJ.^ATT. LATT.CONST. OX 1OE ' FRAC.VOL. CRYST.LATT CxIOC ELEMENT HEXAGOfiAL 3.0160 3.0090 AL20 -0.2300 3. C163 CUBIC 4,0496 HEXAGONAL ALB2 0.5397 <..0496 3.00V0 •:;.'J000, 4.0496 3.2620 HEXA50f:AL 4.751:0 ^-.AL203 1,*.768 M,75S0 12.921,0 HEXAGONAL 5.6400 /3-AL203 •0.0142 5.64C0 22.60CO CUBIC 7.92C0 TS-AL203 -C.1902 7.9200 7.92C0 . 7.95(.0 ^-AL203 -0.1810 cuiiic 7.95L0 7.9500 3.0100 AL20 -0.8049 HEXAGONAL £..0496 TETRAGONAL 12.5000 3.o:^o ALB12 5.0766 CUBIC 12.5000 4.0496 10.2003 5.0C00 4.0496 -o.37::4 riEXAGOl;AL 4, 7i.('.0 0^- AL203 6. 75c;0 12.921.C )J-AL:O3 -0.7430 HEXAGONAL 5.64'JO S-.64 ii.OO-'O a TJ-AL203 -0.7948. cubic 7.92J0 7.9? J0 • 7,9200 " CUtJiC 7f^^ AL203 -0.7924 7.9500 7.95vO 7.9500 o HEXAGONAL 3.0100 10.3000 AL20 -0.7928 4*0496 TETRAGONAL 3.i.:oo AtB12 <».7230 CUBIC 10.3000 4.0496 14.3300 5.C0j0 4,0496 0<-AL203 -0.3336' HEXAGO:jAL 4, 75:10 fc.75:»0 12.9250 -0.7271 HEXAGONAL 5.04 00 ^-AL203 5.6400 22.0000 CUUIC 9200 ^-AL203 -o,7un 9200 9200 9500 AL203 -0.779 6 CUBIC , 95-^0 ,9500 5.5391 -0.4535 CUBIC CUBIC i.26B0 6A0 5.5291 CUBIC 5.0250 p. 53 91 BAB6. Oi225*> 5.0550 '..2680 5.3';58 5.0250 BA02 -0.3585 TETRAGONAL 5:3958 6.;J513 2.6990 0.3960 HEXAGONAL CUBIC 6.3000 BEO 2.6990 9E2B 0.2264 HEXAGONAL 2.2956 M,30OO '..4C10 2.2H56 4.30C0 3.5043 4.7990 CAO -0.6120 CUBIC 5,5020 cubic '..1450 i..7G90 CAB6 0.6378 CUBIC H.:4'>o 4« 7990 ii.6'J20 4.14 50 5.5320 5.4100 -C.2542 • CUBIC TETRAGONAL ?.2050 CE02 5.410C CUBIC 5.1515 7.:C50 5.'-ICO CE64 0.5440 5.1615 4.0900 CUBIC 11.2500 5.1C»15 CC203 -0.1017 11.2*;co 11 .;.50o TRIGONAL 3.^:100 CL203 -C.2561 3.3000 0.joop CUBIC 5.4100 CE.02 -0.4417 5.4100 CllfllC" 5.16:5 CUBIC. , 4.i3;;o 5.'«100 4.1390 5.1615 CE203 -0,3724 CUBIC 11.2500 11.2500 11.2500 Cr203 -0,443I TRIGONAL 3.dB00 3.ecoo 6.0600 COO 0,2225 CUBIC COB 0.C237 HEXAGONAL ORTHORHOMBIC t:m •m HEXAGOf.'AL 4*6500 C0203 0,7044 4.65 JO ;..7600 C0304 0,3921 CUBl O.CU'.O n.co'.o 6.06'*0 i..2603 TETRAGONAL 5.0160 COO 0,4565 CUUIC C02B 0.1950 HEXAGONAL 2.5053 4.2633 2.5053 5.C160 4.2603 4*0886 4.2200 HEXAGONAL fc.CSOO C0203 1,0306 i..6500 5.V600 C03O4 0.6585 CW8I B.ce'*o U.CtiAO 0«C0'.O ^..'.210 4.4ono ^-CR02 1,2397 TETRAGONAL CR3B 0.0597 CUBIC 2.8650 ORTHORHOyBIC 4.^.210 2.3350 5.221JO 2.9100 2.B850 6.62^0 3,6243 ORTHORHOMUIC 5.7430 CR03 t).&5 70 4.7890 CR263 0,6099 HEXAGO'lAL . VJj'.O •4,95'.0 X 13.5e'.0 o CR30 0.2290. cumc 4,*j440 <.,5440 < 4.4210 2.9690 S-CR02 0.6663" T£TRACO.'*AL 0.42A3 CUBIC 2.8650 ORTHORHOKBIC ^..^.210 CRB 2.8850 7.8580 2.9160 2.9320 2.8650 2.4404 ORTHORHOMiUC 5,7^30 CR03 6.5^70 4.70^0 4,9540 CR203 0,4061 HEXAGONAL 4.9540 13.5840 •0.0855 CU3IC Ck20 4,54t.O 4.54'.0 4.4 210 ;.9720 S-CR02 0.2145 TE.TRAGONAL ^-CRB2 0.951.2 CUBIC 2.8850 HEXAGONAL 4 .2 10 2.6850 2.9720 2.9150 3.0690 2.8850 1.5075- ORTMORHOV.bIC 5.7^.30 CR03 8.5570 4.7t90 0.0248 HEXAGONAL 4,9540 CR203 4,9540 13,5840 ^.5440 CR30 . -0.3335 CUBIC 4.5440 C.5^40 4.4210 5.1850 S-CR02 0.96*7 TETRAGONAL 0.2080 CUBIC 2.8650 TETRAGONAL 4.4210 CR2B 2.8050 £.18 50 . 2.9160 2.8050 4.3160 7^.30 C^03 3.0565 ORTHORHO'-'BIC e. J'j70 ^.7C90 t.-JIj'.C CR203 0.6579 • HEXAGONAL 95^.0 13.'jb40 •/..y/.'.O CR30 0,0761 CUBIC 4, 5*.40^ r 1* .7n nrt' n.o70t> TFTPAr.r-NA[ ^i' ' 't.'.PlO r983 CR03 3.0674 ORTHORHOVdIC C.5570 4.7390 £..55^0 CR203 C.0623 HEXAGO.\AL '».9!/*-0 13.5(3-0 .54t-'J CR30 0.0310 CUdIC /*.54'.0 54^.0 4.4210 0.*»903 TETRAGONAL 2.9flt0 S- CR02 t,t.2:o CUBIC 2.6850 ORTHORHOMBIC 13.02C0 -cRae^t 0.5926 2.8830 2.9160 2.9S30 2.0769 ORTHORHO.v.BIC 5.703 2.8850 CR03 8.55/0 4.7890 0.2575 HEXAGOf.AL 4,9540 CR203 4,95'-0 13.5040 CR30 -0.1822 CUBIC f,,'j440 4, ii.-.0 4,4 210 0.9703 T£TRAGOJ;AL ORTHORHOMUIC 14.7K0 ^-CK02 4..*. 2 10 CUBIC 2.8B50 7.3H?C 2.91o0 CR<*B 2.0850 4.2620 t>.74j0 2.3850 CR03 3.0601 ORTHORMOMUIC 0,5570 4.7&'/y 4.V540 CR?03 U.6626 H£XAG0f;AL 13,56^-0 4.54 40 CR30 0.0812 'CuiMC 4, 5'.40 4.54^.0 4.^210 0.7968 TETRAGONAL TETRAGONAL 5.4600 ^- CR02 4,*.210- 0.3209 CUBIC 2.8850 5.4600 2.9160 CR5B3 2.8050 10.6^*00 5,7430 2.8050 Cfl03 2,7097- GRTHORHOMUIC 0.5570 4.7090 4,9540 CR^C3 0.5162 HEXAGOMAL 4,';540 13.5240 4,54'*0 Cf?30 *0.01'*0 CU3IC t ,&t*.0 4.54 40 10.5480 ER203 -0.4717 CUBIC CUBIC 4.1100 10,*.!'. 80 1.2669 HEXAGONAL 3.5588 10, 5^*00 ER06 3.5580 /..llOO 5.5U7*. 4.3C90 TED 0.2121 CUBIC ORTHORHOyblC 5.5060 4.3C90 0.^014 CUBIC 2.8663 2.9520 4.3C90 FEB 2.8663 '..0610 5.4271 2.8663 FF203 0.5263" RHOMBOHECRAL 5,^271 5,4271 8.3940 FE304 0.4933 CUBIC 6,3'>^0 8,3?'*0 4,3090 FED C.'«42 7 CUBIC TETRAGONAL 5.1C90 /.,30?0 0.1774 CUBIC 2.8663 4, -30*;o FE2B 2.ei53 :..2490 5, ^*^71 2.8663 FE203 C.B16n RH0K80HECRAL 5.4271 5,'.271 CUBIC 8.3-740 FE30'* 0.7775 6.3940 8.3940 CUBIC 10.0100 •'•1200 G0203 -0.2323 HEXAGONAL 3.636U TETRAGONAL 7.1200 10.1)000 GDB4 0.5513 3.6360 5.7026 4.0500 G0203 -0.'*332 CUBIC HCXAf.QNAL' ~ - '3./i360 CUBIC 6.1120 1C.8000 5.7826 4,1120 CUBIC 5. 200 3.1969 CUBIC 4.6200 HF02 0.3610 HFB 0.1018 HEXAGONAL 5.1200 3.1969 4.62C0 5.1200 5.0583 4.6200 5.1200 HEXAGONAL 3.1410 HF02 0.1323 CUlilC HFB2 0.3244 HEXAGO^!AL 3.1069 5.1200 3.1969 3.1410 5.1200 5.0503 3.4700 3.9273 . CUBIC 1560 LA203 -0.4270 HEXAGONAL LAB6 0.9346 HEXAGONAL 3.76lO 3.9373 3.7010 4, 1560 0. 1299 6.06.10 4. 1560 4,2130 3.2094 .HEXAGONAL 3.0840 MGO -0.3552 CUBIC MGB2 0.24B3 HEXAGONAL 4.2120 3.2094 3.0840 4.2.130 5.2103 3.5220 . /. a (. 0 ORTHORHOMBIC 5.5600 KNO 4.1168 cubic MNB 0.4054 CUBIC 8.9120 fi.9120 2.9770 i.,4 4'.0 . 4.1450 8.9120 0.61C4 TETRAGONAL ^.. 3950 d- MN02 i.. 2950 2.U6C0 0.7553 ORTHORHOMDIC 9.2 700 ftwi 14.5300 MNO 5.2968 CUBIC N!N4B 0.1420 CUB IC 8.9120 ORTHORHOMBIC 4,4440 8.9120 7.2930 4,4440 J».2090 8.9120 TETRAGONAL 4,3950 MN02 0.9817 ^..3950 2.U600 9.2700 2.8660 4.53 30 /5-MN203 0.8669 CUBIC 9,4ceo 9.40f0, • 9.40f:o • y.N304 0.8725 TETRAGONAL 9.'.4 00 3.1100 K002 0.5932 MONOCLIMC 5.6100 MOB 0.3152 CUBIC 3,1466 TETRAGONA! 4, b4 .}C 3.1468 3.1100 5.5260 3,1468 16.9500 5.5840 »^002 0.6122 MONOCLIMC /.,iii.2J 5W.0U0 0.6202 TETRAGONAL . 0 7 0 J roo2 i.,tJ7ja 2,8000 M003 1,4767 ORTMORHO.v.BrC 13.0500 j,(»9C.O 7J-M0C3 1,4390 ORTMORHOy.lilC 3.ti600 •J.0736 CUUIC 'j . 'J i. V 0 Mo:*o ^.54 90 1,7173 ORTHORMOy.lMC M04011 '^.t.', JO (•.. 7 000 ^^00023 1.6606 MONOCLIMC ic.vooa i3*3nro /i-M09026 1.6296 MONOCUlNIC i4*c:^u'j '..0300 10,7500 3.1600 yoo2 0.5505 MCNOCLINIC 5.6)00 ^-MOB 0.3446 CUBIC 3,1468 ORTHORHOVBIC 4 .!} <• 3 0 3.1468' 3.0800 5.5260 3*1468 Q;5771 .MONOCLINIC '^*5U'*0 M0C2 4,i;420 L-OOtiO 0. 5849 TETKAGO-'.AL <.,a7C0 y002 ...i!700 2. ::OCU 13.:;50-) < ^- M003 1. ^226 ORTHORHOMBIC :i.696C- 3. /6f)0 ^- M003 1.3666 -ORTMORHOMBI.C i3,::-«t;o J.f.6U0 3.92CO Mo:-o •0.0938 CUBIC :.*5490 5*54 90 5.5^.90 ^- M04cn 1.6580 ORTHORHCMBIC 2'.*''000 500 6.7CC3 lo,9000 f06O23 1*6221 MONOCLINIC • '.,0550 t 13.36CO /3-f<09026 1*5722 KONOCUlNiC 1'..''500 '.,C?00 16.7^00 3.0600 MCC2 0.2995 MCNOCLIMC 5.6100 M0a2 0.6129 CUBIC 3*1466 HEXAGONAL '..U'.iO 3,1468 3.'J60C 5.y260 3,1466 3.10C0 MO 02 0.3150 "ONOCLlNiC •j.'.^S'.O. 4. •;4 20 5.6C80 MOO 2 C.3215 TETRAGONAL , i'!703 '.;fi7&0 CfsT MOO3 1.0201 0RTH0RMOM6IC l3.fl5U0 3.6960 2.S660 •^t-MOOS 0,9900 ORTHOFHur'UlC 13.9400 3.6600 3.9200 MO 30 •0,:*443 CUBIC 5.5*t9Q 'j.5490 5.54 90 •J- MD4011 1.2163 ORTMORHOMBIC 2'-, ^.OOO 5. '.500 6.7CO0 ^•C802^ 1 * 18G4 MONOCL IMC .ic.?t.t;o •f 1'«'*. • ••*i 0^5!000 P-M09026 l-.l'.'te KONOCLINIC 16.7500 M02& 0.1671 CUBIC TETRAGONAL 5.5430 M002 0.7954 MONOCLINIC 5.6100 3.1'*&e 5.5^.30 (t.8430 3.1<*68 (..7350 5.5^60 M002 0.0160 MONOCLINIC 5.'^140 C,£,-20 5,60c0 WOO 2 0.8258 TETRAGONAL <..t'70C 2. B000 o(~ M003 1.7909 ORTHCRMOMBIC 13.0500 3.6960 3.9-ifaO '>J- MOOS 1.7A9A ORTHORHO:^BIC 13. :'400 3-6b00 3. ';200 P-.M030 0.0439 CUBIC O.i;^90 5.5490 ^-MOi.011 2,0621 ORTHORHOMBIC 5.t500 6.7000 M0QO23 2.O20B (^.OnOCLlNlC 16.^'OCO '..0550 13-3800 ^-H09O26 1.9633 FOtiOCHNlC 1*..'.500 i..r.3(JC 16.75CO 3.0110 M002 0.1927 KONOCLINIC 5.1.100 M02B5 0*7569 CUBIC 3.1A68 RHOMQOHEORAL 4.0^.30 3.1468 5.5260 3.1 CUBIC 4.2103 N6B 1.9245 CUBIC 3.3007 ORTtlORHOYBIC 3.2920 NBO -C.41*19 3.3007 C.7130 4,2103 3.3007 3.1650 <..2I03 NI302 -0.2255 TETRAGONAL 13.7100 13.71UO S.C'aiC Na205 0.1273 MONOCLINIC 21.':4U0 3,8160 19, 470*0 ' 4,2103 NBB2 0.9156 CUBIC 3.3007 HEXAGONAL 3.0960 riBO .0,0870 CUBIC 3.3007 3.ca&o A.2103 3.3007 3.3060 t.;;103 . Nb02 C.2900 TETRAGONAL 13.7100 13.7100 5.9y50 NB205 0.8777 MONOCLINIC 2U3t.00 3,8160 19.*,7CC 1.3007 nQTHQPHOMUIC 3.3050 NDO 0,0^2 5 CUBIC *..2105. him NB02 0.4449 TETRAGONAL 12.7100 13.7100 5,9860 NB205 1.1032 MONOCLINIC 21,2400 3.8160 IV.4700 3.0500 3.6579 CUBIC 4,1280 ND203 -.0.4510 TRIGONAL ND86 1.0590 HEXAGONAL 4.12B0 2,0500 3.6579 6.0200 I1.7V92 4,i2r.o MO 0.1502 CUBIC 4. 1946 NIB 0.4660 CUBIC 3.52-41 ORTHOPMOMOIC 2.9250 3.5241 7.39t30 1946 3.5241 2.9660 4, 1946 NIO 0.4050 CUBIC 4,1946 NI2B 0*2001 CUBIC 3.5241 TETRAGONAL 4.99C0 4.1946 3.5241 4,9BC0 4.1946' 3.5241 4.2360 CUBIC 5.4695 PRB6 0.0189 HEXAGONAL 3.6725 CUBIC 4.1290 PR0183 -0.4189 3.6725 4.1290 5. t.695 11.8354 4.1290 5. 469'J Pft02 -0.4426 CUBIC 5.3940 5,3V40 5.3940 TRIGONAL 3.8600 PR203 -0.4401 2.d600 (.,0240 PR203 -0.4026 CUBIC 11.C400 11.040U 11,C400 PR6011 -0.9032 CUiilC 5.46P0 5,4 600 5.4680 5.420C RH203 0.2920 RHOMBOHLDRAL 'j.6600 RH2B 0.4588 CUBIC 3.8031 ORTHORHOvOIC it.t600 . 3.8031 3.9800 Ii.460J 3.8031 7.4400 RU02 1.5905 TETRAGONAL 4.5200 RU7B3 0.1974 HEXAGONAL 2.7058 HEXAGONAL 7.4670 (..5200 7.4670 4.1200 4.2819 4.7130 S102.i.-0.3210 MONOCLINIC 7.2300 S1B4 1.4515 CUBIC 5.4306 HEXAGONAL 6.-3300 12.5200 5.4306 6.3300 12.7360 7,23LO 5.4306 Ci- TETRAGONAL 4,9730 SI02 -0.1244 4,9730 6,9500 ^..9130 5102 330 HEXAGONAL t.9130 5,4050 SIC2 0.1223 ORTnORHOMBIC v.e900 17, ICOO 10.3000 S102 ju-0.4743 KONOCLINIC 7.2300 S1B6 2.1661 CUBIC 5.4306 ORTHORHOV.BIC 14.39.:0 12.52CO 5.4306 18.2670 9,8852 7.2300 5,4306 oL' $102 -0.3220 TETRAGONAL 4,9730 '..9730 6.9500 U-^^^V SI02 -0.4061 HEXAGONAL '..9130 4.9130 :-75'-^^yit^SI02 -0.3204 0RTH0RH0^ 4.1980 SI02^-0.5495 KONOCLINIC 7,2300 , S1B6 2.6953 CUBIC 5.4306 CUBIC 12.5200 5.4306 4.1980 4.1900 7.2300 5.43C6 TETRAGONAL 4,9730 SI02 -0.4191 4.9730 6.9500 c/'^iW^ S102 -0.4912 HEXAGONAL • 4,9130 4,9130 ORTHORHOMBIC 9.0900 17.1000 16.30i;o SRO •0.5412 CUBIC 5.1396 SRB6 0.3231 CUBIC 6.0700 CUBIC 4.1960 5.1396 6.0700 4.1980 5.1396 6.0700 4.1960 •0.4310 TETRAGONAL 5.C445 SR02 5.04 4 5 0.6161 TAG -0.0355 CUBIC 4.4220 ^ ' TAB 0.2408 CUBIC 3,3058 ORTHORHOMBIC 3.2760 j'- '..4220 3,3058 8.66V0 ^..^.220 3.3058 3*1570 0 (..7090 TA02 .5161 TETRAGONAL 4. 7090 3.061^0 5.29CO TA20 •0.U46 ORTHOr.HOKBIC t.9 2iJ0 3.05-'^ 3.U1UJ TA205 0.9250 TETRAGONAL 3.C100 35.O70U 7.2300 /?- TA40 -0.1502 ORTHOPHOMBIC 3. ::730 3.211.0 4.4;>20 CUBIC 3.3058 HEXAGONAL 3.0830 (S- TAO "0.1916 CUUIC ^«TAS2 0.4809 3.0P00 4.42Z0 3.3058 4,4^.!0 3.3058 3.2410 TA02 0.2703 TETRAGONAL 4.7UV0 4.70';0 3,0650 TA20 -0.2581 ORTHOHHavOIC 5.2900 4, 92CO 3.05C0 TA205 0.6130 TETRAGONAL 3.01C0 3.0100 35.6700 )S- TA40 -0.2879 ORTHORHOMBIC 7.2380 3.2730' 3.2160 C.0669 CUBIC 4.4220 CUBIC 3.3059 TETRAGONAL 5.7780 5*-TAO /3- TA2B 0.U95 5.7780 4.4220 3.3050 4.42:10 3.3058 <*.e460 TA02 .0.6803 TETRAGONAL 4.70'70 4. 7C90 3.0650 TA20 r0.0l86 0RTH0RH0M9IC 5.2900 4.?2:o 3.0500 TA205 .1.1336 TETRAGONAL 3.01CO 3. Q10C 3 5.67CO ^-TA40 -0.0501 ORTHORHOMBIC 7.230O 3.2720 3.2100 3.2900 -0*1003 CUBIC 4.4220 TA3B4 0.3302 CUBIC 3.3058 ORTHORHOMBIC S" TAO 4.4220 3.3058 14.0000 3.1300 4, ^.220 3.3056 0.4142 TETRAGONAL 4,7C90 TA02 4.7C90 3.0650 -0.1740 ORTHORMOMBIC 5.2?'J0 TA20 4.9200 3.C500 0.7957 TETRAGO.VAL 3.81 JO TA205 3.8100 35.6700 TA40 . 7.2250 -0.2073 ORTHORMOMbIC 3.27JO 3.2U<0 5.5953 THB4 0.6484 CUBIC 5.0843 TETRAGONAL 7.2560 TH02 -0.1914 CUBIC 5.0843 7.2560 5.5953 5.0843 4.1150 5.5953 TH02 .THB6 1.1179 CUBIC .5.0843 CUBIC -0.3706 CUBIC 5.0843 I'.WM 5.59 53 - TIB 0.0954 HEXAGONAL 2.9504 CUBIC 4.2600 TIO -0.0573 CUBIC 6.1770 2.9504 4.2600 6. 1770 4.6833 4*1770 0.6148 TETRAGONAL *.,i>929 ^..5929 2.9591 Ht^iCL^C T102 0.7630 TETRAGONAL 3.7050 3.7050 9.5143 B-tan-Liti' T102 0.664S ORTHORHOMBIC S,15t>0 5,'.470 i/, 1450 TI203 0,3571 RHOyBCrifDRAL 5*4300 5.'.300 5*^.300 TI305 0*5085 MONOCLINIC 9.7520 3.0020 9*4420 -0*1465 CUBIC 1770' T18M 0.2100 HEXAGONAL 2.9504 ORTHORHOMBIC 6.1200 TIO 2.9504 3.0600 t. 1770 ^.6833 *..56C0(J^ ,,02 t. 1770 0.4619 TETRAGONAL 4.&9.-?9 *..5929 2,9591 0.5960 TETRAGONAL 3. TUl/O 3.7050 V.51'.0 0,5071 ORTHORHOMBIC 9, 1050 grw)^^ T102 5.'.470 5. 1450 T:203 0.2285 RHOMBOHEORAL 5.'.300 5**'30C 5.4300 TI3C5 .0,3657 MONOCLINIC V.7i.2y 3.d020 y*'.420 O -0.2887 CUBIC 4.1770 0.4519 HEXAGONAL 2.9504 HEXAGONAL 3.0280 TIO TIB2 3.0200 ^ '..1770 2.950fc '..1770 4.6833 '•""'/ajX 0,2183 TETRAGONAL t, 5929 T.02 i..5929 2,9591 /J-nA^^^ TI02 0.3301 TETRAGONAL • 3.7350 3, 7050 9,5140 BYOH-^M^ T102 0*2560 ORTHOPHOMBIC 9,1B5U ij. 4470 5*1450 0,0230 RH0^^a0HLDRAL 5*^*300 TI263 5*^.300 •^.'.300 TI305 0*1361 MONOCLIMC 9.7520 3. nC20 9,4420 s -0.1437. CUBIC '.,1770 TI2B 0.2060 HEXAGONAL 2.9504 TETRAGONA! 6.1100 TIO 2*9504 '.,1770 4.6833 4. 1770 SlUoo^g^^j^^ 0.4667 TETRAGONAL 4,5929 4, 5929 2.9591 0.6013 TETRAGONAL 3.7850 3.7050 9.5140 0*5120 ORTHORHOMbIC 9. ]850 BHocf>^ T102 5. '.4 70 5. r'.50 TI203 0*2326 RhOMBOHUORAL 5.'•SCO 5.^.300 5.^.300 TI305 0*3701- MPNOCLINIC 9*7520 3.0020 9,4420 TIO -0.3217 CUBIC 41 1770 TI2B5 0.5226 HEXAGONAL 2.950*» HEXAGONAL 2.9B00 2*9504 4,.J77 c 0 <..6033 2.9000 ^ f. 770 TI02 0.16J7 TETRAGONAL '»,L»929 C,5929 2.9591 /bW^CVjA T102 0.2684 TETRAGONAL 3.735U 3.7850 9.5141; (Jyinr^^t^ TI02 0.1977 ORTHORHOXBIC 9. 1050 5.4'.70 5,141;0 5.-.3^0 TI203 -0.0236 RHOMIJOHEORAL 5.4330 ^.^•300 TI305 0.0B53 MONOCLINIC 9. 7520 3. G02C 9.'.A20 3.1360 U02 0.2041 CUBIC 5.C682 UB2 0.6521 TETRAGONAL 10.5200 HEXAGONAL 5.4 6112 10.5200 3.1360 5.4&02 3.9860 5.5700 UC2 0.1855 CUBIC 5.*.i.00 b.t.'.ou 5. ^cOO U03 1.0'^93 CUBIC **, 14(,0 it . lACO 4. li(.0 p- U03 0.6757 TRIGONAL 3.';7iy 2.971U ORTHORHOMBIC 13.01 JO U03 0.9283 1C.7200 7.5100 ORTHORHOMBIC C,29C0 U205 O.6205 31,7100 t,7300 U3O0 0.6326 TRIGONAL C.OI'JO 6. L'150 ^t, 13oO 7.0750 U02 -0.1790 CUBIC 5. '-602 o UB4 1.4232 TETRAGONAL 10.5200 TETRAGONAL 1. -,'.6U2 10.5200 7,0750 3.9790 5,^.602 5.5700 -0.1917 CUBIC 5.4^.00 U02 £,'-A0O 5.4f.a0 ^- U03 0,4312 CUBIC t,, lAbO i . uco 4 , 1^60 H' U03 0,1424 TRIGONAL 2, V710 3,9710 i., 1680 U03 0.3146 ORTHORHOMDIC 13.0100 10,7200 7,5100 U205 0.1103 ORTHORHOMBIC C.H'/OO 31.7100 0.7300 u3oe 0.1130 TRIGONAL 6,8150 6,3150 • ^.,1360 7.4730 U02 -0.6082 CUBIC ?,46e? UB12 TETRAGONAL 10.5200 CUBIC 5.4682 10.5200 7,4730 7.4730 5.4682 5.5700 ft - U02-0.614 2 CUBIC 5.4A00 '^,'.A00 5,4AC0 U03 -0.3169 CUBIC A. 1A6'J 1^4 50 A, W.60 U03 -0.4547 TRIGONAL 3.9710 3.9710 A, 1680 U03 -0.3725 ORTHORHOMbIC 13,0100 10,7200, 7,-»iC0 -0.4701 ORTHORHOMBIC (!.29C0 U2C5 31. 710 J (,.7300 U308 -0.4687 TRIGONAL 6.6150 HEXAGONAL 2.9|b0 VOO'l •0.4064 TETRAGONAL VB2 0.7123 3.C450 3.0570 3*0262 -0.3505 TETRAGONAL 2.9540 V00« :.95*.o 3,5^*00 VO -0.2792 cubic c.C9iU '..0730 C.2340 . MONOCLINIC J..7430 V02 *..5170 5.3710 0.0392 RKOMBOHLORAU L..4S,70 V203 5.'.670 i..i.670 11.5190 V205 0.8836 ORTHORHOMBIC L.3710 0.1400 KONOCLINIC y.9820 V3C5 5.C370 9.G3S0 0.5227 MONOCLlNlC n .9oao V6013 3.6710 10.1220 ^^W02 0.6095 MONOCLINIC 5.56'JO CUDIC. 3.1652 TETRAGONAL 3«1150 i..UV2'J WB* 0.2951 3.1552 3.lir>0 'j.5500- 3.1652 16.9300 TETRAGONAL ^.. 9700 WO 2 0.6054 t.b700 2.7000 MONOCLINIC 3.8350 WO 3 1.5564 7.5170 7.2a'jy 5.25UO WO 3 1.6274 TETRAGONAL 5.2:iOO 3.9150 CUBIC 5.0360 WO 3 2.1098 5.03t)3 5.C.100 TETRAGONAL 7.5 700 W4011 1.6092 7.5700 . 3.7<.i;0 0.6071 M.ONOCLINIC 5.5650 3.J652 0RTH0RH0M8IC 3.1900 (f- W02 «.U920 /3-WB 0.2971 CUBIC e.'tOOO 5.5500 3.0700 3tl652 0.6029 TETRAGONAL 4.8700 WO 2 4. C700 2.70C0 KONOCLINIC 3.0350 WO 3 1,5525 7.5170 7,2850 TETRAGONAL 5.25L'0 WO 3 1.623<* 5.2500 3.9153 2.1051 CUBIC 5.0360 W03 5. C260 5.0360 1.6052 TETRAGONAL 7.5700 W4011 7,5700 3.7400 5.5650 5.5640 0.8019 MONOCLINIC CUBIC 3.1652 TETRAGONAL 5- W02 4, B9rO ^^W2B 0.1568 3.1652 5.5640 5. :;500 4.7400 3.1652 • WO 2 0.7972 TETRAGONAL /..C700 *.,n7oo 2.7C00 W03 1.8619 MONOCLINIC • 7.jei^o W03_ 1.9414 TETRAGONAL 5.25C0 5.2500 3.yi56 W03 2.4814 CUBIC 5.0360 5.C3 00 5.0300 W4011 1.9210 TETRAGONAL 7.5 7C'J 7.57U0, . „ 3.7400 5.5650 ^ W2B5 0*6832 CUBIC 3.1652 HEXAGONAL 2.9820 ^-W02 0.2384 MOMOCLINIC 3.1652 2.9820 4.8920 3.1632 13.8700 5.5500 W02 0.2352 TETRAGONAL 4.8700, 4.8700 2.7t>CO KONOCL INK 3.B350 W03 0.9669 7.5170 • .?at30 TETRAGONAL 5.^500 W03 i.0215 5.25CO 3.9150 CUBIC 5.C36C W03 l'.3927 5.C360 5-.C360 TETRAGONAL 7.5/00 W40U 1.0075 7.b7UO 3.7i.;;0 10.6010 HEXAGONAL 3.64 74 TETRAGONAL 7.0860 Y203 -0.2607 CUBIC YD* 3.64 74 7.0860 10.6010 5.7306 4.0120 10.6010 3.6474 CUUIC 1132 Y203 -0.4050 CUBIC 10.60iy YB6 1.1091 HEXAGONAL 3.6474 1132 10.6010 5.7306 1132 10.6010 7.04 0O YB203 -0.2831 CUBIC 10.4370 YDB^i 0.2005 CUB.IC 5.4P62 TETRAGCNAL 10.4370 5.49 62 7,C4U0 10.4370 5.4062 4.C0O0 4 . 1 4 4'« VQ203 -0.5008 CUBIC 10.4370 YB86 0.7243 CUBIC 5.4862 CUBIC 10 5.4862 4; 1444 .4370 5.4862 4,1444 10.4370 CUBIC 4.5840 ZRB 0.0946 HEXAGONAL 3.2312 CUBIC 4.6700 ZRO -0.0542 4.SS40 3.2312 4,6700 4.i-t)4 0 5.1476 4.6700 2R02 0.3790 , KONOCLINIC 5,14 54 5.^075 5.3107 ZRO -0.2163 .CUBIC 4.5840 ZR82 0.3211 HEXAGONAL HEXAGONAL 3.1700 4,5040 3.1700 4.5840 5.1476 3.5330 5.1'.54 ZR02 0.1426 MONOCLINIC 5.2075 5.31U7 HEXAGONAL 3-2312 CUBIC 7.4080 ZRO -0.7630 CUBIC 4.504C ZRS12 3.3696 7.4080 4.5040 7.4080 4.5840 ZR02 -0.6545 MONOCLINIC 5.14 54 5.i075 5.3107 // DIP •OFLETE OXIDE CART ID 0006 DB AOOR 5594 DB CNT 0013. LATT.CONST. OXIDE FRACVOL. CRY^JgLATT. LATT.C0M5T. CARBIDE FRAC.voL. :RYST.UATT. LATT.CONST CPVRT.LATT. CHANGE ;LEMENT CARBIDE -0.3745 HEXAGONAL 3.C16: (,.0'»96 RHOVBOHEDRAL 8.5500 AL20 AL4C3 0.8935 CUBIC R.5500 3. :i6t; 4.0^.96 0.5500 i.oiie HEXAGONAL 4.750O CR203 0.7514 HEXAGONAL 4.9540 u 13 CR30 0.1389 CUBIC 4.t44u 4. -^4 6 0 4.5i.'*0 6.2900 CSC16 •0.1243 CUBIC 6.0790 HEXAGONAL 4.9503 CS02 0.4502 TETRAGONAL 6.0790 4.9500 •IP.5500 7.i5C0 6.0790 CS2C -C.4954 HEXAGONAL 4,^500 4. ^5t*0 CS30 -0.1497 HEXAGONAL U.TflOO 7.&20O CUBIC /..3C90 •0.0672 CUBIC 2.8663 0RTH0'?MM3IC 5.0n90 FCO 0..8211 fc.:090 2,8663 5.Cfl90 '..3050 2.8663 o.cn92 RHG:'.liGHCORAL 1..2 7 1 (•E203 l.??3: 5. *.271 5.-271 . FE304 1.2437 CUBIC U.394U (;.2943 fa.3940 HF02 0.3426 CUUIC 5. 200 HFC, 0.1169 HFXAGOMAL 3.1969 CUBIC 6.6410 4,6410 5. 203 5.0583 4.6410 :..1200 4,95C0 K02 -0.5195 TETRAGONAL 5.70^.0 KCS 0*5700 CUBIC 5.2470 HEXAGONAL 5.7C4I; 5.2470 4.9500 6.1-990 5.2470 21.3080 K20 -0.7043 cubic 6.44V0 6. '.490 C.''4'>0 HEXAGONAL 4.9500 fC02 -0.4 2 24 TETRAGONAL 5.7040 .tCCl6 0.2039 t.C-SCO 5.7Jtt;; 17.49C0 t.(.990 5.2470 K20 -0.6384 CUBIC 6.4 y J t.'.'.'JU 6.4i«5'J 3.9300 LA2C3 -0*1381 HEXAGONAL 3.';373 LAC2 0.3653 ttEXACOMAL 3.7610 TETRAGONAL 3.V373 3.7610 3.93C0 6.1299 6.0610 6.5600 (.:S0 -C.5625 CUUIC 4.2130 MGC2 0.8401 HEXAGONAL 3.2094 TETRAGONAL 5.&5C0 4.2130 3.2094 5.115C0 *..:i3C 5.2103 CUBIC A.213t 0.3716 HEXAGONM 3.2094 HFXAGONAL 7.fc50C •0.4131 MG2C3 3.2094 7.45C3 <..cl30 5.2103 10.61C0 4.21i0 5.7500 CULIC 6.^^40 MN3C 0.0641 CUBIC 8.9120 ORTHOPHOVDIC S.OftCO y>:o P.9120' 6."'720 ,'.4 C 8.9120 4.53C0 44^,5 yN02 1.1269 TETRAGONAL i.,39*j3 2.i:6CfO yf;02 1.3103 ORTHORHCMDIC 5.2700 2.II&00 4.1)330 Mr;2C3 1.0037 CUBIC 9.'.330 5. 43 CO 5.4 3:10 ••N3C4 1.0397 TETRACO;:AL 5.7600 5.76-0 9.4400 . 4.4(t43 0.1109 CUBIC fi.9120 TPIGONAL 13.9SC0 5*4733 CUBIC MN7C3 8.9120 13.9030 /..'.<.'. 3 8.9120 4*5400 4^.40 1.0373 TCTRAOOMAL 4.2950 ^- MN02 .4.3950 2.U6C0 1.2206 ORTMORHOMBIC 9.2700 /I-VN203 0.9193 cubic VN304 0.9250 TETl^Af.Or'AL 5.7600 5.76LC 9.4400 M002 0.6000 MONCCLWMC 5.C1JV MOC 0.3097 CUBIC 3.1468 HEXAGONAL . 2.9320 '..;;^30 3.1<'6e 2.93?0 3.1460 10.9700 5.52CC M002 0.6190 MCNCCLIMC <. • :!^2C M0C2 0.6271 TETHACONAL 4.1:700 4,::7CC CO .'•'.003 1.4871 ORTHORHOMDIC 13.n5CC 2.6960 1.4501 ORTMC.'?HO^'.BIC ?..9CC0 ^•0C3 i3.';4cs 3. w600 V.^'030 -0.0696 CUBIC 5.5490 5.i.4yc; 1.7207 ORTMOnHOVGIC 5.54 90 ^'.04011 2/.. '.:oo 5.4 5C0 1.6919 y.ONOCLlNiC f.,7CC0 V0fl023 1C.9000 4.3550 1.6407 y.ONOCLlNiC i3.3i;oo y09O26 14,45C0 '..:3:o 16. 7 50-:' woe 0.2296 CUBIC 3.1468 HEXAGONAL 3.0100 M002- y.7093 KONOCLIKIC 3.1468 3.0100 5.6100 3.1468 14.6100 M002 0.7302 y.CNOCLlMiC 4. ri4 30 5.S.2tO 5.5040 V002 0,7309' TETRAGO'JAL 4,r.4 2C 4.u70J 2. f:0C0 ^- V003 1.6579 '0RTH0RH0Vb.IC .13.C5wO 3,6960 3. ';660 M0O3 1.6184 0RTH0RHOM13IC 13.9400 3.6600 3.92C0 V030 -0,0057 • CUUIC 5.5490 5.54 90 5.5490 lS-y0401l 1.9161 ORTMORHOMbIC 24,4COO 5.4500 6.7000 V.08023 • 1.8768 WCNOCL If: IC 16.9000 4.i.550 13.380C /3-K09026 l.y220 MONOCLINIC 14.4500 4. 'J3C0 16.7b00 5.6100 3.1468 3.0C2C y.002'- 0.7721 MCNOCLiniC M03C 0.1825 CUBIC HEXAGONAL 3.0020 4.2^.30 3.1468 5.5260 3.1468 4.7240 KOOZ 0.7932 MCNOCLINIC 5.5640 4.0420 5.6CtlO MOO 2 0.8021 TETRAGONAL 4.U700 4.0700 Z.0CC3 M003 1.7547 ORTHORHOVBIC 13.U5C0 3.6900 3.9600 7^- .V003* 1.7137 ORTHORHOYBIC 13.9400 3.6600 3.9200 M030 0.0303 CUBIC 5.5490 0.5490 5.i»490' ^-V040ll 2.0223 ORTMORHON'BIC M0eO23 1.9815 KQNOCLINIC lt.9C0v 4,Ca50 13.3iiO0 MONOCLINIC 14;4D00 M09026 1.924B 4,0200 16.75-0 CUBIC 4.4700 f.BO 0,114 1 CUBIC .:!o3 NBC 0.2416 CUBIC 3.J007 4,4700 4 4.470C 4 . 2 1C 3 3.3007 TETRAGCNAL J3.71'JC NB02 0.5744 12. 7U-0 5.9fi5C MONOCLINIC 21.34.': Nn205 1.2917 3.i:luO 19.4700 ND203 -0.1903- TRIGONAL 3. n5 03 0.3962 HEXAGONAL 3.6579 TETRAGONAL 3.9100 3 • (1 'j w C N0C2 3.91CU 6.C20C il'Mll 6.2400 2.6502 MIO 7.3950 CUBIC 4,1946 -0.7991 CUBIC 3.5241 HEXAGONAL 4. 1946 NI3C 3.5241 2.6002 4. 1946 • 3.5241 4.3383 MPO -0.0023 CUBIC .LuU 0.4258 ORTHORHOMBIC 4.7230 CUBIC 004 0 ..wOOO NPC 4.88 70 ,0040 ^.C50C 6.6630 .0040 CUBIC 5.4300 NP02 0.2819 5.'.3(»0 5. 4 360 5.4691* 3.8600 PR0IG3 -0.1407 Cubic •0.3109 HEXAGONAL 3.6725 TETRAGONAL 5.*«695 PRC2 3.6725 3.86C0 1^.4695 11.8354 6,39C0 cubic 5.3940 PR02 -0.1756 5..3540 < 5.3940 TRIGONAL 3.::6:0 PR203 -0.1640 3. (.6 J- 6.0240 H' CUBIC 11.C4GC PR203 -0.1166 ll,c400 11.C400 CUBIC 5.46b0 rR60ll -0.0569 5.46110 5.46^0 PUO 0.0233 CUDIC 4. V500 0.4ft69 MONOCLINIC 6.1833 CUBIC 4.9200 PUC . 4.6244 4.9200 4.-;5r.o 10.9730 4,9200 4. v5*-0 PU02 0.3192 CUBIC 5. 5, ;960 5.2960 PU203 0.2767 TRIGONAL 3 .4 o >^ 3.o4c;0 CUBIC 5.V570 OU203 0.3761 1C.S45: K-.94i0 lC.'v4 50 PUO -0.0924 CUBIC 4.C5li0 0.6767 MONOCLINIC 6.1B35 CUBIC 9.1290 4.';oj;o PU2C 4.8244 B.3290 10.9730 R.1290 4. ';5'ic PU02 C.1599 cubic 5.3?oC 5. ;96C 5. :V6C PII203 0.1323 TRIGONAL 3.114:0 3.':4C0 5.9570 Pl.'203 0.2204 CUDIC 1C.C45C 1L.V45C 1C.9450 RU02 0.0526 TETRAGONAL 6. -ICO 0.301.3 CUBIC 5.7000 HEXAGONAL 4.9500 (i.ClOO PBCB 5.7000 4.9500 22.7C00 5.7000 PB:O -c.680t; CUBIC urn RD406 .-0.5910 CUBIC 4.9500 Rtj02 0.3329 TETRAGO.'iAL 6.0100 RBC16 0.0301 CUBIC 5.7000 HEXAGONAL ^.OluO • 5.7000 4.9500 7,C400 9.7000 17.9900 P320 -0.5958 CUBIC C.7560 6.7 500 U.7560 RR4C6 -0.4695 cumc 9.32C0 ^.3200 9.3200 3.0C17 SIC2^ .0.0007 MONCCLIMC 7.Z3C-0 SIC 0.0346 CUBIC 5.4306 HFXAGONAL 12.5200 5.4306 3.0P17 37.7960 7.£2:0 5.'»306 TETRAGOIJAL 4,9730 0(- SI02 • 1.0745 4.9730 6.9500 oL-'ll^J^^ SI02 0.0173 MEXAGOIiAL 4.9i:c 4.9130 5.4c:,o 1.0795 CRTHORHOrbIC 9. £'900 17. ICOO u.3o:o S102, 0.6106 MOMOCLIMC 7.2300 .0334 CUBIC 5.4306 HEXAGONAL 3,onoo 0(- SIC 0 9.4306 • 3.01*00 ir. :,:uc 9.4306 15.1174 7,2300 oC' SI02 1.0770 TCTRAGO::AL 4.9730 4.9730 C.?5U0 S102 0.13194 HEXAGO:-.AL 4,';i;o 4.9i:o 1.0819 CRTHORH0W13IC 9.C900 17. If 00 R.5CC0 3.0117 C.6087 f;ONOCLJJ:IC 7.23c6 0(«SIC 0.0346 CUBIC 9.<»306 HEXAGONAL 12.5200 5.4306 3.CP17 10.07SC 7.2300 5.4306 1.0745 TETRAGONAL 4.y7 30 V. S102 4.9730 6.95^0 0.8173 HEXAGONAL 4./ISO 4.9130 5.4CjU 9.«500 SI02 1.0795 ORTHORHO-bIC I7.:::c 16.3COO 7.2 300 3.0"17 SI02 0.6095 MONOCLINIC ^.SIC 0.0341 CUBIC 5.4306 HFXAGONAL 12.52D0 9.43Q6 3.0nl7 7,2300 52.8900 5.'»306 TETRAGONAL 4.9730 1.0755 4.9730 6.9500 HEXAGONAL 4,9130 3.079C / SI02 C.6125 MONOCLINIC 7.2300 tX' SIC 0.0321 CUBIC 9.4306 HEXAGONAL lZ.t»20 0 9.4306 3.0790 7.2300 83.1000 5.4306 TETRAGONAL 4.9730 (5i-'SI02 1.0795 . 4.9730 6.9500 4.9130 SIO^ 0.8216 HEXAGONAL 4- . 9 ISO 5- . 4050 CRTHORMOfCIC 9.8900 ^.r^^-rw^ SI02 1.0344 17.1000 lfc.20C0 SIC 0*0347 CUBIC 9.4306 CUBIC 5102L 0.6004 WOMOCLINIC 1 • ^ 2 ^ C 5.4306 4.3597 7.2:30 5.4306 6^- SI02 1.0742 TETRAGONAL 4.?753 4.073C 6-55CV *..513C oC-^UA^^ SI02 0.0169 HEXAGONAL 4,':-130 0^-'^u^0Vvji*'S102 1.0791 ORTHORHCVBIC 9.'.9:3 16 SRO -0.4439 CUBIC 5.1396 CUBIC 6.0700 cuurc 6.2500 5. 396 sr?C2l 0.0916 6.0700 6.2500 6'.^5C0 5.1396 6.0700 SR02 -0.3103 TETRAGONAL 5.C44 5 5.:44 5 C.C161 TETRAGONAL 4.1200 SRO •0.4022 CUBIC 5. 1396 . SRC2(i:) 0.0155 CUBIC 4.1200 5.1396 6.0900 1396 6.0700 SR02 •C.2507 TETRAGONAL 5.;'4i.5 5.:4'.5 6.6161 4.4564 c^-TAO •0.0229 CUBIC 4.'.2iC TAC 0.2248 CUBIC 3.3050 CUBIC 4,'.2 23 3.3058 4.4564 t**.964 4.'.2 20 3.3050 0,5359 TETRAGONAL 7093 ^- TAC2 /,.7C53 2. :65u TA20 . •0.1030 0RTH0RHC*'UIC L.z';co '..•;2-o 3 • U 5 0 - JL- TA205 0.9502 TETRAGONAL 3.1! U3 3. ^133 3^.6733 TA40 -0,1391 . ORTHORHCMblC 2.:"733 . 3.2163 ^.TAO 0,0490 ' CUBIC ^..'.2 20 TA2C 0.1407 CUBIC 3.3058 HEXAGONAL 3*1042 3.3058 3.1042 4.4220 3.-3058 a.94 10 ^-TA02 :,6492 TETRAGOKAL i..7:V3 4. 7C90 TA20 -0.0363 ORThORHCMBIC :.;;650 5.2930 4.9230 0^- TA205 1.0943 TETRAGONAL 2. C5C3 J..': 133 3 . 'j 1 00 /i— TA40 -0.07 56 ORTHORHOMBIC 35.67Cw 7.23i:0 3. :730 3.2U0 TMC2 -0.0050 CUBIC 5.59*^3 THC2 0.3406 CUBIC 5.0843 MONOCLUMC 6.3300 5.0043 4*2400 5.5953 5.0843 6.5600 5.5953 0.1766 CUBIC 5.591>3 THC 0.1327 CUBIC 5.0843 CUBIC 5.3000 TH02 5.5953 5.0843 5.3000 5.5953 5.0843 5.30C0 •0.1004 CUBIC 4.1770 TIC 0.1479 HEXAGONAL 2.95C4 CUBIC 4.3270 TIO 1770 2.9504 4,3270 4.1770 4.6833 TI02 0.5410 TETRAGONAL 4.5929 4.5929 2.9591 /)7lAi5t ^roT.^*^ TI02 0.5886 ORTHORHCyi-.IC TI2C3 0.2950 RI'Of-'UOHEOnAL TI3C5 0.4395 MONOCLINIC 5.t6?2 TETRACOK'AL 10.5200 CUBIC 4.9550 U02 0.3440 CUBIC uc 0.4R01 4,9550 4 61.2 10.5200 5. 4 if. 2 5.5700 4.9550 /J'U02 0.3233 CUBIC 5.440C 5.4400 5.44i0 U03 1.34 3 2 CUBIC 4 . 1 J 4. 1400 4. 14^;, ^-U03 C.3704 TRIGCr.AL 3. V71C 4. i6t:o 3.5240 U02 C.097 3 CUBIC 5.'.6-:: 0.B12P TETRAGONAL 10.5200 TETRAGONAL 5.40^^ UC2 10.5200 3.524C L.4&.:2 • 5.5700 5.9910 U02 COCO 4 CUBIC 5.4 40'J /3- 5.4M;C 5.41.00 CUBIC 4. 14 bJ ' U03 C.V13 2 4. 1400 . :4C« ^^.UC13 0.5272 .TRICOr;AL 3, '-'710 :. 0 71 u 4, 16JU 0.2361 CUBIC 5.46C;; TETRAGONAL 10.5200 CUBIC UC2 'I2C3 0.6093 n.crpo i..1.6^2 10.5200 5, <<6ii2 5.5700 o.onno 0.2171 CUUIC 5.4i«u0 /J- UC2 5.4400 5.4400 CUBIC u,1460 UC3 1.1551 4.1460 I. .1460 0.7203 TRIGONAL 3.V710 ^. U03 3.9710 4.1680 -0.2279 TETRAGONAL 3.0450 CUBIC 3.0282 CUBIC J.1820 voo-i 3.0450 VC 0.3169 3.0282 3.C450 4,1.820 3.0282 TETRAGONAL 2.9540 V005 -0.1553 2.9540 3.5400 CUBIC 4.0930 vo -0.0624 4.0930 4,0930 MONOCLINIC 5.7430 V02 0.6050 4,5170 5.3750 5.4670 V203 0.3516 RhONBOHEDRAL 5.4670 5.4670 11.5190 V2C5 1.4503 ORTMORHOMBIC 3.5550 4,5710 -;.903O V3(.'5 C.4027 MONOCLINIC 5.0370 \r.ti350 0.9805 MONOCLIMC II. VOOJ V6013 3.t710 IJ.U^U 3.04 50 2.9360 V0--1 -0.1597 TETRAGONAL V2C 0.2100 CUtilC 3.g2S2 HCXAGCKAL 2.9C6C 3.0282 4.5970 3.C430 3.0282 V0C5 -0.0006 TETRAGONAL :.5 540 2.9540 3.5400 CUUIC 4.0'/30 VC 0.0203 4.093W '..-9 30 y,ONOCLii;ic 5.7430 V02. 0.7463 4.5170 5.j75a V2C'3 C.4710 RHOiiLOHCOiJAL 5.4670 5,46/3 5-^670 :i,519;> V205 1.6664 OP-THO-rHOKLIC 3.55/0 V305 C.6137 ;.:onoCLi:;ic y,*-i;20 ;»,w3/o V. J.S'^i V6013 1.1554 r'.or-DCLrac lU.12^0 5-56t'J •0.6909 CUcJiC 3.1652 HEXAGONAL 2.9063 .v02 10.1239 MOMOCLINIC 3.1652 2.9:63 4, (, •:•; 3 3.1652 2.H36b 5.55o0 K*C2 13.0743 TET.'^AGCf-AL 4.f 7LJ 4. }. 7 '* 2.7-;^;; V.03 29.3730 MONOCLI.MC 3.t.3 50 7, 1.1V0 n03 30.2174 TETRAGONAL 3, '.-r.o •.•;03 35.y4-;o CUBIC 5. -360 5.:360 5.-36- '.•.'4011 30.0013 TETRAGOf.AL 7.57-3 7.5700 3.74CC 5.5650 0.3315 CUBIC 3.1.|2 RHOMBOMEORAL 3.5000 0.5655 MONOCLIMC W2C 3.5000 4, P.9:0 3.5000 O 3,1652 4, ,"703 W02 0.5614 TETRAGONAL X 4.i;7:: 2.73i^U •»;o3 1.4865 MONOCLINIC 3. tt350 7.5170 7.205C wo 3 1.5555 TETRAGOr:AL 5,25i;0 5, £5C0 3.9150 »:03 2.0247 cubic 5.C3C0 5.03'-0 5.C36C W4011 1.5376 TETRAGONAL 7.5700 7.5 7'JJ 3.7400 5.5650 W2C 0.1570 CUBIC 3.1652 HEXAGONAL 2.9943 0.0017 MONOCLIf.lC 3.1652 2.994h 4. r:y:c 3.1652 4.7262 5,5500 '.•.'02 .0.7970 TETRAGONAL 4, F'.7C0 4,l'7uC 2.7800 •//03 1.8615 nONOCL W\IC 3.1-250 7,51 /: 7.:c50 "...03 1.9410 TETRAGONAL 5. ^500 5.25^/0 3. V150 ;v03 2.4C:0 CUUIC 5.'w-360 5.C-360 5.C360 W4011 1.9207 TETRAGONAL ;.57C0 7.57'JO 3.74:.0 ZRC 0.1130 HEXAGONAL 3.2312 CUBIC 4.69 60 iUO -0.069U CUbIC 4. '5240 3.2312 4.6960 4,5840 5.1476 4.6960 4.5840 2I02 0.3562 r.ONOCLINlC 5.1454 5. ^075 5.31U7 (cxiii) APPENDIX V BINARY BOaiDSS IN THE PERIODIC TABLE AI^ PROPERTIES OF IMPORTAI'TT BORIDEo AiMD C/\RBIDS.S (cxlv) . . Binary boridcs in the PcrirdicTfb!o Ln » bnih=nidc. in parcn:hi.-L'» » unfcnmn. = ut il cnnPrnud. 1. h = low -ind hich tcmrvr..iurc5 . VllA VIIIA IB IIB IllB lA IIA IIIA • iVA VA VIA LiB, Hc,D B.-B. HcB., MpB,: • AlD,.i>V-.M O.jB CuB...)?» KB» lCaB:» St-B. TiB |-,B. 04fl \fr.^B Co-B Ai.B CaB* TiyBi rs O.B Frit NtjB-io-NtjBj.J CaU. TiBj r,H. O.B, CoD I',fl. OB m-N'ijB, I'.B, •toB, Miitt, \fB IBj OB. MnU^ OB, Rti.Bf K/i-Bj PJjfl (RbB,» SrB» VB. Zi-flj .Vh./I. .\tn,B 7V,B KB, Mo.B: Ru,,B, RhB-,.i IB. .\>,B, 1\P. fiuB,,.i VB,, Mi'R: RK.B, ye.. Ru'Uj Moti~A ^* Binary boridcs in iho Periodic Tablo 1.inihani(!c. in parenthc^M =• unrcrizin. iialic^ *> »cll confirmed. I. h lou- and hieh icmpcraturet I-'. IIA niA IVA VA VIA VIIA VIIIA IB MB IIIB tCsBj U,8 /;/B, ro.B ir,B Rc.B? 0*B.,. /rflo,ilI PtjB LaBj R»;D O^.fl, //fln.ih» Pl.Bj LaBt TaB ll'Bj Rr,n, Oifl; /'fl-,, P*B Rc,II? Os,B, /rB, ToB, RcD Rc,U,? Re,B.7 RtB, LnC. . ;Cd.Tb.Dy.Ho.t:r.Lu;B... ;Dy.Lu;D,. arctno«n 7hB* t'flj .VpB, PuBf?) AmBt TftB» VBt Npfi» FuB, AmD^ fB,, .VpB. rt.B4 A'pfl,, PuB. PuO PuB ieo M.P. 2,230 2,235 2,230 Density g.crnT^ 2.49 3*39 4.26 Resistivity 222.0 191.8 77 Microhardness 2,700 2,920 3,000 Kg.mm. ^B^Me ^-37 0.36 Crystal structure C C C Thernal expan- 6.5 6.7 6.8 sion/°C X 10^ Energy of crystal 1,230 1,220 1,200 lattice K.cal.Hole"^ Co-efficient of 1.16(0-100) 0.83(0-100) 1.08(0-100) electrical resis• tivity /deg. X 103 Co-efficient of -30.3 -26.2 absolute thermo e.m.f.Q(^ . l-iV degT-^ AH^298 '^-cal.Hole"^ ^ -50.4 Modulous of elas- 46,000 39,300 ticity Kg.nmiT^ YB LaB, M.P. °C 23 P 2,530 Density g.cniT^ 3.64 4.76 2.52 Resistivity 40.5 1? io6 Microhardness 2,770 xvg •ram-*2 0.88 Crystal structure Thermal expan- 6.2 6.4 sion/°C X 10^ Energy of crystal 1,780 1,770 lattice K.cal.Mole Co-*efficient of electrical resis- 1.24(0-100) 2.68(0-100) tivity/deg. x 10^ Co-efficient of absolute thsrmo 0.5 +7 e .m.f. , m deg -1 -1 AH^^^g K.cal.Mole -24 112.3 -13.8 + 2.7 Modulous of elas 48,800 _p ticity Kg.nun. t'/.VU T132 ^2 Hf3^ M.P. °C • . 2,980 • 3,040 + 100 3,250 + 100 Density g.cmT^ 4.5(4.52) 6.17(6.09) 10.5(11.20) Resistivity 9-15 16.6 8.8 Microhardness 3,370 2,252 2,900 Kg.mm. Crystal structure H H H Thermal exnan- „ , o „_ sion/"C X 10" Energy of crystal 3^260 2,540 lattice K.cal.Mole C0"9fficisnt of electricL=.l resis- 2,?8(300-2000) 1.76(300-1800) 3.6(20-2630) tlvity/des." x 10^ Co-efficient of absolutabs olutee thermthermoo -5.1 1»2 e .ra.f. p( , IN deg 1 AH^298 ^^•cal.Mole"*'- -6? -76.7 Nodulous of elas- ^^^^0^ 3^^000 tlcity Kg.mm V3B, VB. NIDB, M.P. °C 2,350 2,400 + 50 3,000 Density g.cmT^ (5.46) 5.28(5.10) 6.97(7.00) Resistivity 19 34 Microhardness 2,350 2,800 2,600 Kg.ran. ^B^Me Crystal structure H H Thermal expan- 5.3 8.1 sion/°C X 10^ Energy of crystal 2,880 3,060 lattice K.cal.Mole Co-efficient of electrical resis- 3.16(100-1100) 1.39(100-1100) tivity/deg. x 10^ Co-efficient of absolute thermo 9.2 1.4 -1 e.ra.f. p( , m deg -1 AK^298 ^-cal.Mole 36 Modulous of elas• 27,300 ticity Kg .mmT'^ IaB2 Pi% Cr^B M.P. °C 3,100 1,750 Density g.cmT^ 12.38(12.62) 4.53 (6.24) Resistivity 37.4 19.5 176 Microhardness 2,^00 2,470 1,240 Kg.mmT Crystal structure H C 0 Thermal expan- 11.5 7.5 sion/^G X 10^ Energy of crystal 2,940 1,730 8.2 lattice K.cal.Mola" Corefficient of electrical resis- 1.48(100-1100) 1.92(0-100) 1.13(20-100) tivity/deg. x 10^ Co-efficient of absolute thermo e.m.f. , I-IV degT-*- Modulous of elas- 26 200 ticity Kg.nimT^ CrB CrBg Ho3 M.P. °C 2,050 2,200 + 50 .2,350 Density g.craT^ 6.05(6.11) 5.22(5.60) -8.2-8.3(8.77)- Resistivity 69 84 . 45 . Microhardness ^^250 2,100 2,350 Kg.mmT^ Crystal structure .0 H . T Thermal expan- -L^^X sion/°C X 10*^ Energy of crystal 2,140 1,870 lattice K.cal.Mole"-^ Co-efficient of electrical resis- 3,26(20-100) 2.61(20-100) tivity/deg, x 10^ Co-efficient of absolute therno -0.94 -O.OJ e.m.f, d( , l-N degT**- i^^H^^f^Q-K.calAiole'-^ -3O -16.3 Modulous of elas- 50O ticity Kg .minT^ .' CXXl Mo3. V/B M.P. °C 2,100 2,100 2,400 + 100 Density g.cmT^ (7.78) 7.01(7.48) 15.30(16.0) -• Resistivity 45 18 Microhardness 1,200 2,350 3,700 Kg.mm. Crystal structure H R Thermal expan- sion/°C X 10^ Energy of crystal lattice K.cal.Mole Coi-Gfficient of electrical resis- 3.3(100-1100) tivity/deg. x 10^ Co-efficient.of absolute thermo 3.2 e .m.f. p( , MV degT"^ AH^298 K-cal-Mole"-*- 23.0 50.0 1.2 rr -22 Modulous of elas ticity Kg.mm -2 HdB, Fe,B M.P. °C 2,300 + 50 2,540 1,339 Density g.cm. 17.0(13.1) 4.86(4.94) (7.32) Resistivity 43 20 36 Microhardness 2,663 2,540 1,340 — 2 KP .mra. 0.63 Crystal"structure H T Thermal expan- 7.3 sion/°C X 10^ Energy of crystal 1,780 lattice K.cal.Mole Co-afficient of electrical resis- 4.26(100-1100) 1.93(0-1'30) tivity/deg. x 10^ Co-efficient of absolute thermo 3.2 0.4 -28 -1 e.m.f. 0( > deg. -1 ^H^298 K'Cal.Mole -25 - 45 -6 Modulous of elas 2.9 X 10 ticity Kg-mmT^ FeB ^S^A SiiB^ M.P. 1,540 2,540 Density g.cni:3 7.15(6.1?) (5*08) (4.95) Resistivity 80 207 84.7 Microhardness — 2 Kg.ram. «B/^Me Crystal structure 0 C C Thermal expan- g^g sion/^C X 10^ Energy of crystal 1,780 1,220 lattice K.cal.Hole"-^- Co^-efficient of electrical resis- -0.42(0-100) 0.9(0-100) tivity/deg. x 10^ Co-efficient of absolute thernio -14.2 7.6 -17.7 e.in.f. J IN deg,""*" ^^f298 K-cal.Mole"-^ Modulous of elas- ^ ^ ,^-6 _p i.> X lu ticity Kg.mra."^ cXXlV GdB, TbB/ YC 2 M.P. °C . 2,100 •• 2,300 Density g.cmT^ 5.0(5.30) (5.36) 4.13(4.58) Resistivity - ~ 88.7 Microhardness 2,300 2,300 7O8 Kg.imnT^ Crystal structure Thermal expan- g^r;- r^^g sion/°C X 10^ * . Energy of crystal ^^^r^^O 1,790 lattice K.cal.Mole"-^ Co'^efficient of electrical resis- 1.4(0 - 100) l.^liO - 100) tivity/deg. x 10^ Co-efficient of • absolute ther^-no 0,1 -1.1 -0,8 e.m.f. , m deg~^ i6H^298 K.cal.Mole"-^ Modulous of elas• ticity Kg.mraT^ uc TiC H.P. °C 2,020 2,315 3,147 Density .g.cm. (6.079) 12.97(13.63) 4.93(4.92) Resistivity 144 100 52.5 Microhardness 77 923 2,470 Kg .nun. 0.41 0.51 0.52 Crystal structure Thermal expansion/ 9.9 10.4 7.74 °C X 10^ Energy of crystal 3,890 lattice K.cal.Mole Co-afficient of electrical resis- 1.16 tivity/deg. x 10^ Co-efficient of absolute thermo 1.1 -11.2 e.m.f. ^ , iv/ deg' -1 AH^293 K.cal.Hole -42 -40 -43.85 Modulous of elas 46,000 ticity Kg.mm. • ZrC HfC VC M.P. °C 3,530 3,890 2,810 Density g.cml^ 6.73(6.66) 12.2(12.6?) 5.36(5.48) Resistivity 50 45 65 Microhardness 2,925 2,913 2,094 Kg.mm. Rc/^Me -^--^ ^--9 Crystal structure C . . . C C Thernial expan- ^^^^ g^^g sion/^C X 10^ Energy of crystal ^^^^0 . 2,800 3,900 lattice K.cal.Mole" Co-efficient of electrical resis- 0.95 1.42 tivity/deg. x 10^ Co-efficient of absolute thermthermoo ^ -11.3 -11.7 3*7 e.m.f. M7 de AH^298 '^-cal.Mole"-*- -47*7 -50 -30.2 Modulous of elas- 35,500 35,900 43,000 ticity Kg.mmT Nb^C NbC TaC M.P. ^C 3,480 3,380 Density g.cm- 3 7.86(7.85) 7.56(7.39) 14.3(14.4) Resistivity 51.1 42.1 Microhardness 2,123 1,961 1,599 -2 Kg. mm' 0.53 Crystal structure PH Thermal expan- 7.0 6.65 6.29 sion/^C X 10^ Energy of crystal 2,570 3,220 2,770 lattice K.cal.Hole Cd-efficient of electrical resis 0.86 1.07 tivity/deg. x 10 Co-efficienf of absolute thermo -4.0 5.0 e.m.f. !••?/ de2. -1 AH^293 K.cal.Hole -34 -34.3 Modulous of elas- 34,500 29,100 ticity Kg.mm'- 2 cXX v//f ^23^ ^7% ^3^2 H.P. °C 1,550 1,665 1,895 Density g.cmT^ 6.97(6.99) 6.92(6.92) 6.68(6.74) Resistivity 127 109 75 Hicrohardness ^^g^O 1,336 1,350 Kg.mm. Rc/Ri.i3 0.57 Crystal structure C H 0 Thernal expan- ^^^^ 10^^ IO.3 sion/°C X 10^ Energy of crystal lattice K,cal.Mble""'" Co-efficient of electrical resis- 1.72 1.06 2.33 tivity/deg. x 10^ • Co-efficient of absolute thermo 2.76 -7.1 -6.7 e.m.f. ^:H^298 K.cal.Mole"-*- -25.8 42.52 -21.01 Modulous of elas- ^8 000 ticity Kg.nmT^. M02C MoC M.P. °C 2,410 2,700 . 2,730 Density g.cmT^ 8.9(9.167) 3.4(8.88) 17.2(17.34)-' Resistivity 71 75.7 Microhardness l,'f-99 3jOOO Kg.mmT^ Hc/^He Crystal structure FH H PH(0) Thermal expan- .^^g ^^g sion/^C X 10^ Energy of crystal 2,280 2,000 lattice K.cal.Mole"-*- Co-efficient of electrical resis- 3*78 1.95 tivlty/deg. x 103 Co-efficient of absolute thermo -1.9 -8.17 e .m.f. ^ J MV degT^ AH^298 ^^.cal.Hole"-^ -4.2 -2.0 -7.09- Modulous Of elas- ^^^^^^ ^^^g^^ ticity. Xg.mn. cxxx WC M.P. °C 2,720 Density g.cmT^ 15.-6(15.77) Resistivity 19.2 Microhardness 1,780 — 2 Kg.mm. Crystal structure H Thermal expan- 3.84 slon/^C x 10^ Energy of crystal 2 76O lattice K.cal.Mole"-^ ' Co-efficient of elec• trical resistivity/ 0.495 deg. X 103 Co-efficient of absolute thermo e.m.f. -23.3 o< , IN degT-*- ^H^298 K.cal.Mole"^ -9.1 Modulous of elas- 7I 000 ticity Kg.mmT^ ' <]'D>0Q