UK ISSN 0032-1400
PLATINUM METALS REVIEW
A quarterly survey of research on the platinum metals and of developments in their application in industry
VOL. 31 APRIL 1987 NO. 2
Contents
Platinum in the Glass Industry 54
A Study of Platinum Alloy Welds 62
Solidification in Microgravity 62
Industrial Fuel Cells Forum 63
Copper and Nickel Alloys Clad with Platinum and Its Alloys 64
Hydrogen Permeability at Elevated Temperatures 71
A New Type of Molecular Conductor 72
More Organometallic Compounds 73
Some Ternary and Higher Order Platinum Group Metal Alloys 74
Platinum and Palladium in Astronomy and Navigation 91
Abstracts 101
New Patents 108
Communications should be addressed to The Editor, Platinum Metals Review Johnson Matthey Public Limited Company, Hatton Garden, London EClN 8EE Platinum in the Glass Industry ZGS MATERIALS SUPPLEMENT CONVENTIONAL ‘ALLOYS By J. Stokes Johnson Matthey Materials Technology Division, Wembley
Platinum and its alloys have long been accepted as essential materials for the fabrication of equipment used in the glass industry. However the superior mechanical properties of the zirconia grain stabilised materials developed by Johnson Matthey have led to their successful utilisation for many of the most demanding applications; for others conventional platinum group metals and alloys are still preferred and both types of material are considered here.
The platinum group metals are characterised high quality optical or crystal glasses are being by high melting points combined with excellent manufactured. Pure platinum is therefore chemical nobility. These properties are par- preferred in such high quality glass applica- ticularly useful in the glass industry which tions, even though the generally higher melting manufactures a multitude of end products. The points of these glasses limits the service life of range includes domestic glass as tableware or the platinum, due to grain growth and soften- cookware, flat glass for windows, crystal glass ing with time. for prestige domestic use, optical glass, radia- In some areas of the industry control of the tion shields, and fibres for reinforcement and glass flow rate is crucial to the success of a for- insulation, along with many others. Glasses in ming or processing operation. In such cases the their most basic form are combinations of soda, tendency for glass to wet platinum surfaces lime and silica together with other modifiers results in adhesion and poor flow and refiners, which melt at high temperatures characteristics. To overcome such problems 5 to form aggressive liquids. per cent gold-platinum can be used, an alloy Platinum with a melting point of 1769OC is which can be described as non-wetting to one of the most inert of the platinum group molten glass. Although limited by a lower max- metals, and is suitable for applications at imum operating temperature the use of this temperatures up to approximately q5o0C, alloy has enabled increased glass flow control although at these high temperatures softening and improved operating efficiencies. due to grain growth reduces the materials’ abili- All conventional platinum group metals and ty to withstand stresses and hence limits their alloys exhibit softening with time at service life. temperature, and consequent reduction in The addition of rhodium, typically 10 weight ultimate strength due to recrystallisation and per cent, to platinum produces a much stronger grain growth; in addition deformation occurs alloy which can be used under more highly by creep. These factors limit the life of many stressed conditions, and with some gain in max- fabrications so Johnson Matthey have imum operating temperature. However, the developed a range of Zirconia Grain Stabilised high initial cost of rhodium tends to limit its use (ZGS) platinum alloys which do not suffer from as a platinum strengthener to about 20 per cent. this undesirable loss of strength (1,2,3,4). One disadvantage in the use of rhodium is ZGS materials have a fine, evenly dispersed, that it tends to colour the glass yellow under discrete, second phase of zirconia, present certain conditions. This limits the applications throughout their matrix. These particles then of rhodium containing platinum alloys where slow down the processes of degradation
Platinum Metals Rev., 1987, 31, (2), 54-62 54 Fig. 1 During production of the discontinuous fibres used for heat insulation a steady stream of molten glass from an elec- trically heated feeder bushing is poured into a rapidly spinning basket. After hitting the base of the basket the molten glass is thrown outwards by the cen- trifugal force, forming fine fibres as it passes through the orifices in the cylindrical wall of the basket. The stream of fine fibres leaving the basket and then falling downwards under the force of gravity can be seen on the left-hand side of the il- lustration Photograph by councry of Gvproc Insularion Limrtd
dramatically. They achieve this by pinning hence initial cost) for a given level of stress, dislocation networks formed during thermo- (iii) enhanced resistance to intergranular cor- mechanical processing, so inhibiting the move- rosion, ment of these dislocations to the grain boun- (iv) operation at higher service temperatures. daries. This process of dislocation movement is Zirconia grain stabilised versions of one of the steps that precedes grain boundary platinum, rhodium-platinum and gold- movement and competitive grain coarsening, platinum alloys are used extensively in many leading to the removal of the highly anisotropic areas of the glass industry. structure developed during the manufacturing operations. As a consequence, softening occurs Glass Fibre Production and the ability of the materials to withstand The manufacture of continuous glass fibres stress with time at temperature is severely requires the use of a platinum containing com- diminished. With ZGS materials microstruc- ponent called a “bushing”. In essence, turd degradation is effectively restricted, giv- bushings are rectangular open topped boxes ing extended operating lives when compared to having bases with numerous precisely shaped conventional platinum group metals and alloys. orifices, called “jets”, through which the fibres Another benefit of ZGS materials is that of are drawn. In the process of glass fibre improved resistance to intergranular con- manufacture, molten glass or glass beads are tamination. This is achieved through retention fed from above into the bushing, heated to the of the high aspect-ratio grain structure, which operating temperature by direct electrical provides a long and tortuous route for in- resistance heating, and then drawn through the tergranular contaminants to travel. As a conse- jets in the baseplates. Individual glass fibres are quence, the critical intergranular crack length combined to form roving which in turn can be for failure is increased; this is shown in Figure woven into mat, and using a laying-up process 2. In summary, the use of ZGS alloys in the and a resin binder large high strength fabrica- glass industry gives the following advantages: tions can be made, for example car bodies. (i) greater strength with time at temperature, Chopped strands of roving can be added to a and hence longer service life, resin for use as a high strength moulding com- (ii) the ability to reduce cross-section (and pound or for local reinforcement of glass rein-
Platinum Metals Rev., 1987, 31, (2) 55 Fig. 2 When both conventional and ZGS platinum and its alloys are subjected to high temperatures, of say 14OO0C, while under stress, there is an opportunity for any surface contaminants to move into the material along grain boundaries. In the case of conventional alloys (left) the worked structure is replaced by equiaxed grains between which the impurities (shown in blue) can move readily, especially normal to the direction of the stress, so weakening the section. However, with ZGS materials (right) there is only very limited grain growth and the grains retain their elongate shape. Although the impurities again move along the grain boundaries the direction of movement is mainly parallel to the direction of stress, so the section retains its mechanical in- tegrity for very much longer
forced plastics. Yarn which is produced from hundreds of filaments twisted together is usual- ly processed into various kinds of cloth, tapes, sleeves, etc., and used for electrical insulation and pipe mouldings. For the glass fibre producer the Noble Metals Group at Johnson Matthey has developed a pro- prietary process for the manufacture of baseplates with high precision and excellent metallurgical integrity. Using this process, some 5,000 baseplates have been produced in the United Kingdom and over 30,000 worldwide by Johnson Matthey associate houses. The method of baseplate manufacture re- quires the use of special equipment and tools of the highest precision and quality. This is necessary to ensure a high degree of bore con- centricity. If concentricity is bad then thinning of the wall in part of the section will occur and in operation a hot spot will be formed. During fibre production the hot spot will lower the viscosity of the glass at that point and it may flow back up the outside of the jets. This leads to flooding of the baseplate, as glass flows among the jets, and prevents fibre production. Single baseplates with up to 2,000 jets and hav- ing widths up to I 10 mm have been produced; using a modular construction far greater numbers of jets are possible. The jets can be aligned in longitudinal or transverse rows, and within each row the jets can be arranged in a rectangular format or with 6oo offsets. Such
Platinum Metals Rev., 1987, 31, (2) 56 Fig. 3 Typical stress data for conventional rhodium-platinum alloys, and for the Johnson Mat- they range of ZGS platinum alloys at 14OO0C, showing the superiority of the zirconia grain stabilised materials
arrangements allow for logitudinal or transverse The latest development to improve bushing cooling fins, which may be nickel, palladium or economics is the use of ZGS 5 per cent silver. The jets themselves may have bore rhodium-platinum, which has superior diameters from 1.1 mm up to 2.5 mm and mechanical properties to conventional 10 per lengths 2.25 times their bore diameters. Wall cent rhodium-platinum. The reduced initial thicknesses may be as low as 0.25 mm while jets cost of the alloy, resulting from the lower with thicker walls can be counterbored. rhodium content, has proved most acceptable Baseplates manufactured from platinum and as it has not reduced the life of the bushing. rhodium-platinum have been used for many By establishing a close relationship with glass years for the production of glass fibres having fibre producers and working with them over diameters in the range 25 to 10pm. Below this many years, Johnson Matthey have gained con- the wetting of platinum by glass results in siderable experience in baseplate and bushing poor glass flow through the fine jets, and thus manufacture. Johnson Matthey have now continuity and diameter are severely affected. licensed their fabrication processes to glass pro- Use of the non-wetting gold-platinum alloys has ducers in a number of countries. enabled fibres with diameters as fine as 6 pm to be produced economically and with bushing ef- Discontinuous Fibre ficiencies in excess of 90 per cent. The use of High quality fibres have a high recovery fac- ZGS platinum, rhodium-platinum and gold- tor such that following compression during platinum alloys has overcome one of the major packing, delivery and long term storage, the operational limitations of a conventional mat will recover to its original thickness and bushing, namely baseplate distortion. give optimum heat insulation. This necessitates Since the development of ZGS materials the use of a platinum or rhodium-platinum bushing lives have increased by over IW per spinner basket, which is used in conjunction cent, significantly improving the economics of with a platinum group metal feeder bushing. fibre manufacture. Through the introduction of The feeder bushing can be heated by electrical ZGS baseplates the use of high rhodium con- resistance, either directly or indirectly through tent alloys has become less necessary. Addi- the use of a rhodium-platinum coil situated tionally, the higher strengths of the ZGS around the orifice ring. The purpose of the materials have enabled lighter bushing bodies, feeder bushing is to provide a steady stream of with thinner wall sections, to be used. glass of homogeneous composition and closely
Plarinum Metals Rev., 1987, 31, (2) 57 baskets has been declining recently due to the use of modern high strength superalloys, which were introduced for economic reasons. However, the life of superalloy spinner baskets may be limited by erosion and distortion of the orifices, resulting in a reduction in the yield of dimensionally acceptable fibres. An improve- ment is achieved using a platinum-containing alloy, so most insulation fibre manufacturers do retain platinum group metal spinner baskets in their production lines. Through the introduction of ZGS rhodium- platinum alloys the operating lives of spinner baskets have been improved significantly. The added strength helps to reduce bowing of the basket walls during service. ZGS rhodium- platinum feeder bushings similarly have been introduced where the combination of high strength and resistance to contamination has in- creased operating lives. Optical Glass Production Glass for use in optical applications must be Fig. 4 By means of high speed photography it of extremely high quality. In this case the quality is possible to record the glass fibres leaving a determining factors are consistent homogenei- spinner basket and then falling downwards, as gravity overcomes any residual centrifugal force ty, a high degree of transparency and high Photography by counny of Cypm lnsulmian timired transmittance of light. Transparency is affected by coloration and controlled viscosity, from the forehearth to the bubbles, seed and blisters within the glass. spinner basket. Many of these problems were associated with Several different licensed methods of produc- the use of refractories within critical areas of the ing insulation fibre find applications glass manufacturing process. Through the throughout the world. The essentials of all selective introduction of platinum into the key these methods rely on a spinning basket bet- areas of melting, conditioning and forming, ween 150 and 600 mm in diameter whose high quality optical glass can be produced. walls contain accurately drilled orifices. Glass Pure platinum and ZGS platinum are the from the feeder bushing strikes the base of the preferred materials since, as stated earlier, the spinning basket and is then thrown outwards use of rhodium-containing alloys leads to col- and upwards whereupon it passes through the oration of the glass. orifices due to the centrifugal force. The In the melting furnace, platinum is used for streams of fibres produced are then broken up bubbler tubes, electrodes and, occasionally, as either by a second rotating spinner or by an at- a lining material in small furnaces. Skimmer tenuating flame, depending on the process blocks which remove surface debris from the employed. Fibres of glass, typically between 9 glass prior to conditioning are common, and and 25pm, then fall under gravity onto a con- consist of a refractory block clad with platinum veyor belt where they are agglomerated through sheet, typically 0.5 mm thick. However with addition of a binder. ZGS platinum a typical cladding thickness The use of platinum group metals for spinner could be only 0.3 mm, giving a significant re-
Platinum Metals Rev., 1987, 31, (2) 58 duction in the weight of the platinum employed. high quality domestic ware. In order to achieve Optical glass is conditioned to remove bub- consistently high quality, platinum melting, bles, seed and blisters, to ensure homogeneity conditioning and processing equipment is now of composition and to give close control of used throughout the industry. In many cases temperature, all of which are crucial to the the low throughput of glass by crystal manufac- quality of the product. The most common turers dictates that batch melting techniques method of achieving these aims is through the are used. In these types of operation large use of a refining or fining system made from platinum crucibles, often up to 500 mm in platinum. Generally tubular in section, the diameter, are employed for the melting stage. design of these items is proprietary information The use of ZGS platinum has extended and varies from plant to plant. Following the operating lives, increased resistance to attack signing of non-disclosure agreements with glass from contaminants and in addition, in some producers, Johnson Matthey have manufac- cases, it has enabled the weight of the crucible tured many such items. to be reduced. Larger crystal glass manufac- At the forming stage in the manufacturing turers use small continuous furnaces and in process secrecy again limits the amount of free- these cases platinum linings are often used. ly available information. However, platinum is Conditioning in platinum finers is carried out used for flow control devices, stirrers and gobb- in a similar manner to that for optical glass pro- ing units, most of which are made of clad duction. Again the objective is to produce glass refractory. for the forming operation that is homogeneous In summary, the high quality of modern op- with respect both to composition and tem- tical glasses results from significant use of perature, as well as being free from bubbles. platinum and ZGS platinum in key areas. At the forming end a plunger operating above an orifice ring controls the size of the glass gob, Crystal and Tableware Glass and rotation of the plunger ensures constant Production temperature throughout the gob. The orifice Crystal glass generally relies upon the addi- ring is made from platinum and the plunger is tion of lead oxide to give it high transparency, generally a piece of refractory material clad colour purity, a high refractive index and to in- with platinum. crease its density. It is a combination of these In the case of tableware the use of platinum factors which makes crystal glass such a is generally confined to the forming end of the desirable material for cutting and faceting in process where pressing or blowing takes place.
Fig. 5 With good insulation, direct electrically heated platinum forehearthe provide an eficient means of produc- ing consistently high quality optical glasses
Phoiqlrsph by COUK~~of EGLASSTREK GmbH
Platinum Metals Rev., 1987, 31, (2) 59 Reaction of Platinum with Miscellaneous Substances (5)
Substance Results of reaction, and/or comments
Sodium or potassium carbonate, fusion Only very small losses occur during mixture, alkali bifluorides, borax normal fusions Sodium nitrite or nitrate Up to 1-2 mg loss on fusion Alkali chlorides, alkaline earth chlorides Attack on metal above 1000°C, especially at air line Alkali bisulphates Attack occurs above 7OOOC Magnesium pyrophosphate Attack occurs above 900°C Alkali oxides, peroxides, hydroxides, When fused will rapidly attack platinum sulphides Sulphuric acid, hydrofluoric acid, alkali Evaporations may be carried out with hydroxides, sodium peroxide little loss Hydrochloric acid No attack if oxidising agents absent Concentrated phosphoric acid or P,O, Noticeable reaction on prolonged heating Hydrochloric acid + oxidising agent (e.g. Rapid attack aqua regia) Fused cyanides Platinocyanides formed Selenium, tellurium, phosphorus, All attack platinum arsenic, antimony, lead, tin, zinc, bismuth, etc. Iron oxide, lead or bismuth oxides Reaction occurs above 1200-1 25OOC Air, nitrogen oxygen, oxides of Negligible effect nitrogen, bromine and iodine vapour, carbon dioxide Ammonia, sulphur dioxide, chlorine, These atmospheres cause attack on volatile chlorides platinum Hydrogen, carburetted gases or Encourage reduction of a wide range of vapours, luminous gas flames, reducing substances at elevated temperatures. gases Must be avoided Organic ignitions, coal Burn off carbonaceous materials at as low a temperature as possible with access of air More stable oxides, AI,O,, MgO, TiO,. Ignitions possible without attack ZrO,, etc. ZnO, Co,O,, NiO Ignitions should be carried out in CdO and other reducible oxides oxidising conditions Silica, silicates Attack under reducing conditions above 1ooooc
The supply of glass to a pair of shear blades is glasses differ considerably with their composi- sometimes through a rhodium-platinum down- tion. In the case of (heat-resistant) opal glass draw tube. This conditions the glass to some manufacture, extensive platinum cladding is extent but also controls the flow to the forming necessary at the forming machine supply end of machine. the forehearth. With other glasses, platinum The corrosive and erosive properties of cladding of refractory metals such as molyb-
Platinum Metals Rev., 1987, 31, (2) 60 denum is necessary only at or around the only an approximation of sub-surface tem- gladair interface. perature and viscosity can be made. A far better The use of a paddle plunger or a gobbing stir- temperature measurement and control arrange- rer clad in platinum or rhodium-platinum is ment is made possible by the use of immersion often used in high output operations. These in- thermocouples in the furnace and forehearth. clude feeds to independent section presses or These assemblies contain multiple thermo- spinning machines used to produce tableware couples which enable temperature to be and stemware, such as wine glasses. measured at various depths within the glass. The temperature and aggressive chemical con- Temperature Measurement ditions require that these assemblies are In all sectors of the glass industry sheathed below the glass line with a rhodium- temperature measurement and control is of ex- platinum alloy. treme importance. With temperature change, ZGS 10per cent rhodium-platinum is prefer- glass viscosity and flow rate can vary red for this use because of its excellent con- significantly and the subsequent control of glass tamination resistance, and its ability to function forming and processing operations is impaired. at high operating temperatures. Additionally, Gob size and homogeneity are, for example, of the high strength of the alloy means that only prime importance in the production of crystal thin sheaths, typically 0.5 mm thick, are need- glass and precise temperature control is crucial ed to protect the alumina. in the control of these factors. The use of ZGS 10 per cent rhodium- The use of standard alumina sheathed platinum has proved extremely successful even platinum-rhodium/platinum thermocouples for in the most chemically aggressive glasses, for measuring furnace crown temperatures has example the amber glass which is used exten- been common for some time. However, the hot sively for container manufacture. atmosphere above the molten glass often con- tains exhaust gases from combustion of the fuel Other Glass Industry Applications and vapour phases from the batch, either of Two-ply glass tubing is used for the manufac- which can attack the alumina sheathing and ture of low pressure sodium vapour lamps. affect thermocouple accuracy. This problem is Here a 10 per cent rhodium-platinum mandrel compounded by the increasing number of is used to bring a controlled thickness of special refractory materials used in furnace lin- sodium-resistant glass into contact with the ings and by some of the more exotic glass addi- outer glass at a predetermined rate. tions which can be incompatible with alumina. In the aerospace industry limited use is made The use of 10 per cent rhodium-platinum as a of glass which is coated with thin films of sheathing material over the alumina had proved platinum and rhodium. to be successful in overcoming these problems. In the case of oil fired furnaces the presence of Conclusion traces of sulphur-containing gases can lead to The platinum group metals and alloys possess direct attack on platinum group metals, or to chemical and physical properties which occur the reduction of refractory oxides which can in unique combinations that make them par- then cause attack. The use of ZGS 10 per cent ticularly suitable for many applications in the rhodium-platinum as a sheathing material has glass industry. significantly reduced the number of failures As glass manufacturers have striven to im- due to contamination. prove the quality of their established products, Measurement of molten glass temperature is to achieve economies in production and to an area where radiation pyrometers are used ex- satisfy the demand for new materials, the tensively. However, such systems only measure platinum suppliers have contributed improved the temperature of the glass surface and as such fabrication techniques and alloys with superior
Platinum Metals Rev., 1987, 31, (2) 61 properties. In particular the use of ZGS References platinum and alloys has given improved service I G. L. Selman, J. G. Day and A. A. Bourne, life, reduced metal inventories, and improved Platinum Metals Rev., 1974, 18, (z), 46 z G. L. Selman and A. A. Bourne, Platinum Metals resistance to contamination, thus extending the Rev.,1976, 20, (31, 86 applications for platinum in the glass industry. 3 R. B. McGrath and G. C. Badcock, Platinum The continuing close relationship between sup- Metals Rev., 1987, 31, (I), 8 pliers and users will present further oppor- 4 A. E. Heywood and R. A. Benedek, Platinum Metals Rev., 1982, 26, (3), 98 tunities for progress to be made in glass 5 A. G. Knapton, Platinum Metals Rev., 1979, 23, production technology. (I), 2 A Study of Platinum Alloy Welds THE EFFECT OF HYDROGEN CONCENTRATION Considerable experience of the use of Russian journal Avtomaticheskayu Svarka being platinum alloys for glass-melting apparatus has sponsored by the British Library Lending Divi- now accumulated, and this shows that a key sion, and published by The Welding Institute, factor determining service life can be the in- Abington, Cambridge, England. tegrity of the alloy in the proximity of welded joints. Brittle fracture of platinum alloys can Solidification in Microgravity result from contaminants entering the weld during fabrication or use, and a recently Gravity induces significant disturbances in reported investigation by 0. D. Smiyan, B. I. gaseous and liquid systems. These disturbances Shnaider, D. M. Pogrebiskii, L. A. Potapenko are manifested in the form of buoyancy, and E. I. Butkova of the E. 0. Paton Welding sedimentation, thermal convection and Institute of the Ukraine SSR Academy of hydrostatic pressure. All these phenomena af- Sciences has considered the effect of welding fect the solidification characteristics of liquid technique on crack initiation and development metals and alloys. By carrying out a solidifica- (Avt. Svarku, 1986,395, (2), 10-12, 29). tion process in a microgravity environment, The alloy used was platinum-20 rhodium-Io gravity-induced disturbances are virtually palladium-o. I iridium-o. I gold, in the form of eliminated and the solid structures produced a disc of 0.5 mm thick sheet which had been an- are unique in uniformity of composition and nealed for 30 minutes at 10ooOC.Concentric properties. welds were made by plasma micro-welding, Undercooling experiments have been carried either under an argon +hydrogen atmosphere out on a number of refractory elements, in- or without a protective shielding, while the cluding platinum, rhodium, iridium and perimeter of the disc was held rigid. ruthenium, in the free-fall microgravity Microstructure, hardness and composition (Io-6g,,; IXIO-~Torr) environment of the were examined and it was concluded that this drop-tube facility of the Marshall Space Flight alloy is highly resistant to crack formation dur- Center by W. H. Hofmeister, H. B. Robinson ing welding, that the use of the protective at- and R. J. Bayuzick (Appl. Phys. Lett., 1986~49, mosphere does not affect the results, and that (201, I342-!344). there is a relationship between welding se- Both platinum and rhodium achieved an ex- quence and the hydrogen distribution. Under pected cooling rate of between 17 and 20 per unfavourable conditions the local hydrogen cent of their melting temperatures whereas concentration can vary by more than 2: I, and iridium and ruthenium undercooled between may account for the reduced strength of some 10 and 13 per cent. The latter effect was welded joints. associated with heterogeneous nucleation caus- It is suggested that the formation of concen- ed by impurities. A high degree of undercool- tric welds, where the stresses are expected to in- ing on solidification is an important crease as the diameter of the circular weld phenomenon in the production of amorphous, increases, is a convenient way of evaluating the single crystal and metastable phase structures. weldability of a material. Clearly microgravity research is providing an An English language translation of this paper understanding of material behaviour which will appears in Automatic Welding, 1986, 39, (2), lead ultimately to new Earth- and Space-based 13-1 5; this cover-to-cover translation of the products and processes. I.R.M.
Platinum Metals Rev., 1987, 31, (2) 62 Industrial Fuel Cells Forum EUREKA INITIATIVE TO HASTEN COMMERCIALISATION
American and Japanese work on fuel cells has trodes to improve the economics of this type of received considerable coverage in this journal cell. The alkaline fuel cell was described by Dr. over the past decade; much less has been writ- Van den Broeck of Elenco, Belgium, who refer- ten about fuel cell activity in Europe. Although red to the 40 kW Elenco alkaline cell intended Elenco, Siemens and others have worked suc- for stationary power generation; this will soon cessfully on alkaline fuel cells there has been commence first stage trials. only very limited activity on phosphoric acid Three groups of participants then explored the and other fuel cells. For these reasons a Eureka possibilities of formulating commercial projects forum on fuel cells was held in London during between member countries. The low power February under the chairmanship of Dr. G. J. (0-5 kW) session, chairman Mr P. R. Wyman K. Acres of Johnson Matthey. Over 100 people of the G.E.C. Hirst Research Centre, con- from fourteen European countries attended. sidered the markets for small fuel cells based on Eureka is an initiative, taken by the govern- their perceived advantages. Potential uses were ments of Europe, which is focused principally identified at remote, unattended, tele- on the commercial exploitation of new communication stations; for consumer leisure technologies for non-military applications. Fuel activities where absence of noise and pollution cells have been identified as an opportune topic may be more important than initial cost; for for a Eureka programme which will bring isolated residential power supplies and for together the necessary European catalyst, elec- European space applications. The medium trochemical and engineering expertise. The power (5-150 kW) session, chaired by Mr. K. Keynote Speech was given by Dr. D. Pollard of Gussgard of the Norwegian Water Resources the G.E.C. Engineering Research Centre who and Energy Administration, again identified noted the Japanese projection that by 1995 the uses which depend upon the particular advan- market for phosphoric acid fuel cells will tages offered by fuel cells in this power range, amount to 1000 MW/year, using platinum elec- including high efficiency, low maintenance re- trode loadings of 2gkW. quirement and clean, quiet operation. In addi- The current situation was highlighted in tion to the applications identified for the papers on phosphoric acid, solid polymer and smaller units, potential outlets were seen for alkaline fuel cells. These systems, which are all combined heat and power systems where motor platinum catalyst based, provide the only op- generator sets are currently used, and for portunity for short to medium term commer- powering city buses. The high power output cialisation of fuel cells. The phosphoric acid (250 kW-11 MW) session, chairman Mr. G. fuel cell system was described by Dr. L. J. M. Hoffmann, Ruhrgas, F.G.R., established that a J. Blomen of Kinetics Technology Interna- significant market existed for electricity genera- tional, The Netherlands. His company is col- tion and district heating schemes but that col- laborating with Engelhard Industries to laborative projects would be necessary if manufacture fuel cells in Europe. Their present Europe was to respond effectively. In par- aim is to develop a 25 kW fuel cell, intended for ticular, the limited European capability in computer power and similar requirements, bas- platinum electrode and stack technology was ed upon a commercially available 5.6 kW unit. seen as an inhibiting factor. Dr. S. Stucki of the Brown Boverie Research This forum may be seen as the key event Centre, Switzerland, described a solid polymer which will stimulate European activity in this electrolyte cell which uses platinum or oxides of high technology business, and create a major ruthenium and iridium loaded onto the elec- new outlet for platinum. J.E.P.
Platinum Metals Rev., 1987, 31, (2), 63 63 Copper and Nickel Alloys Clad with Platinum and Its Alloys THE IMPORTANT INFLUENCE OF DIFFUSION By D. Ott and Ch. J. Raub Forschungsinstitut fur Edelmetalle und Metallchemie, Schwabisch Gmund, West Germany
Cladding base metals with platinum or platinum alloys offers certain technical and economic advantages. In an earlier paper the mechanical properties of the metals to be joined were discussed. In this second paper it is shown that interdifiion of the two materials being joined together must be considered, and that ifthe partners have different diffusion coef- ficients diffzculties can result during later production stages. This is especially true ifvoids form in the diffusion wne due to the Kirkendall effect. This effect is particularlypronounced when copper alloys are used as the base metal, however it can be avoided either by using nickel-rich alloys or by incorporating an electrodeposited intermediate nickel layer of suitable thickness.
The mechanical cladding of non-precious that are well suited to this process (I). Now, in metals or their alloys with precious metals, this second part we will discuss the diffusion especially gold and gold alloys, is well establish- behaviour between the various components, ed. The technology was first developed for and its importance to the cladding process. jewellery applications, where to some extent it was later replaced by electroplating. However Experimental Work growth in the electronics industry resulted in a Initially attempts were made to join platinum revival of mechanical cladding for selectively sheet, 0.5 to ~mmthick, to the respective base coating copper- or nickel-based materials with material by cold rolling. To enable the sand- precious metal-containing alloys for contact ap- wiched materials to be reduced by rolling it was plications. In the main gold or palladium alloys necessary to improve the adhesion of the two were used for this application. Mechanical clad- layers immediately after cladding, by heat treat- ding enables a wide range of thicknesses, from ment. It was established that if this annealing Ikm upwards, and a nearly unlimited selection was carried out at temperatures above 650OC of alloys to be used. Since the process involves for about 0.5 hours in a vacuum better than alternating mechanical deformation and heat 10-' torr the adhesion was very poor, indeed treatment, to improve the adhesion of layers, it appeared to be worse than before the heat important parameters are the deformation treatment. On samples annealed at characteristics and the diffusion behaviour of temperatures above 7moC for 0.5 hours it was the metals concerned. observed in all cases that the platinum had In the first part of this two paper series we separated from the copper base. The platinum discussed and compared the deformation sheet-at 0.5mm much thinner than the 2.0mm characteristicsof base metal alloys with those of copper base-appeared torn and heavily wrink- platinum and platinum alloys, which are of in- led. Scanning electron microscopy showed that terest from a cladding point of view. It was the originally contacting surfaces now displayed shown that it is possible to select combinations characteristic features, which are shown in
Platinum Metals Rev., 1987, 31, (2), 64-71 64 Fig. 2 The surface shown is that of platinum which has parted from the copper, to which it had been roll bonded, following annealing at 9OOOC for 48 hours
samples, heated in the critical diffusion temperature range, showed that voids had formed on or near the original contacting sur- faces after only short annealing times. These are illustrated in Figure 3, which is of a sample where the voids formed after an initial diffusion treatment and were sufficient to cause separa- Fig. 1 When a sandwich of platinum-5 per cent tion of the platinum from the copper base. This iridium/copper, formed by cold rolling, was an- microsection shows that both the original con- nealed for 72 houre at 8OOOC separation occur- red. Scanning electron microscopy showed that tacting surfaces are now rough. Due both to the the two surfaces which were originally in contact stresses resulting from heat treatment and to had now developed characteristic forms. The progressive weakening as diffusion alloying copper side of the diffusion zone is shown above in both electron micrographs, the magnification caused voids to grow with time, the interface of both being indicated could no longer bear the load and in many places the top separated from the base. However in some areas contact between base Figures I and 2. It was discovered also that the separation was much less pronounced when nickel was clad with platinum. In order to check the possibility that the poor adhesion was caused by impurities-especially oxides formed during cladding-molten copper was cast onto platinum. When the resulting sandwich was rolled down to 1.2111111the adhesion remained fairly good. Additionally copper and nickel layers ~mmthick were electroplated onto platinum and/or platinum alloys, and a copper sample was platinum plated in a fused salt bath. However after heat treatment for longer than I 5 minutes in the temperature range 600 to 800Oc Fig. 3 Different diffusion rates have caused poor adhesion or even separation still occurred Partial Separation of the Platinum laye" from the copper base. The volume of the platinum has on all these samples. been increased and there is a zone of voids Metallographic examination of diffused within the copper x 55
Platinum Metals Rev., 1987, 31, (2) 65 however form a fascinating topic for further work. In order to study the diffusion behaviour without the formation of voids produced during the initial cladding stage, the apparatus describ- ed in the earlier paper for high temperature ten- sile testing was used. Sandwiches of platinum and platinum alloys with base materials (each in the form of squares with sides of about ~omm) were annealed to the cladding temperature- Fig. 4 This interface between platinum and which in most cases corresponded to the later electrodeposited nickel shows no hole formation annealing temperature-and held for I 5 after annealing for 8 hours at 700’C x 125 minutes at a pressure of I to 8kN. After the pressure was released and the sample cooled, and top remained, and here diffusion and hole the adhesion was good in all cases. Typical formation continued. This progressive diffu- microstructures of the diffusion zones produc- sion and transfer of copper into the platinum ed in this way are shown in Figure 5. These shows up as a thickening of the platinum layer “pressedy7 samples were generally annealed at these places, the copper-platinum alloy form- without pressure so that the hole formation ed by the diffusion process being more porous could be observed, and so that the conditions than the original platinum foil (2). The separa- approximated to those likely to be met with in tion of platinum from copper and copper based service. They could, however, have been car- alloys, following heat treatment, is therefore an ried out under pressure in the tensile testing inherent problem caused by different diffusion machine. rates or mass transfer of metals in contact with During pressing a nitrogenh per cent one another, the so-called Kirkendall effect hydrogen atmosphere was used, and later an- (2,3). The metal with the faster diffusion rate nealing was carried out in a vacuum better than diffuses into the other metal and leaves behind IO-~torr. All samples were cold rolled after voids which are not filled by the slower diffu- the diffusion processes, and in general the sion of the other metal. Eventually the voids reduction prior to an annealing step was at least combine along the diffusion interface to pro- 50 per cent. duce the type of structure shown in Figure 3, In a series of experiments we established the and thus the adhesion gets worse. best conditions for obtaining good adhesion of This also explains the observation, shown in pressed samples. For the alloys under con- Figure 4, that the Kirkendall effect is less with sideration annealing at 7m°C for 20 minutes a nickel base, since the diffusion coefficient of while pressurised at 5kN was found to produce nickel must be smaller than that of copper due the best results. At lower loads or for shorter to the higher melting point of nickel. times the adhesion between the platinum com- The experiments also suggest that the ponent and the base metal could be poor. order-disorder phenomenon contributes, Good joining, that is where there were few or either by influencing the diffusion or the no pores, occurred with the’following systems: stresses at the interface. The critical (i) copper/platinum, (ii) copper-25 per cent temperatures of ordering, 615OC for PtCu, and nickel/platinum, (iii) copper-25 per cent 812OC for PtCu, are a possible reason for the nickeVplatinum-5 per cent cobalt, and (iv) critical temperature range of 600 to 8m°C copper-25 per cent nickel/platinum-5 per cent observed during the diffusion experiments. iridium. This was not studied in detail as it was outside Difficulties occurred with platinum-5 per cent the scope of the research programme. It would cobalt/copper or copper-tin (6 or 8 per cent).
Platinum Metals Rev., 1987, 31, (2) 66 Fig. 6 After 50 per cent cold deformation followed by annealing for 4 hours at 8OOOC a porous zone, resulting from the Kirkendall ef- fect, is shown in a platinum-5 per cent cobalt/copper-8 per cent tin diffusion couple x275
Fig. 7 After 50 per cent cold rolling followed Fig. 5 Unetched microsections showing the dif- by annealing at for hours the porous fusion zones produced when sandwiches of noble 7oooc 'One in lhis platinum/copper-8 per cent tin diffu- metal and base have been annealed at 700 0 for C sion couple is thinner than that shown above in 2o minutes under 5kN pressure, followed by Figure 6 x275 cooling to normal pressure. The platinum-rich layersare on top in each case x275 (a) Platinum/copper (b) Platinum-5 per cent cobaltlcopper (c) Platinum-5 per cent iridium/copper-25 per cent nickel
In order to show the various degrees of void formation that occurred during diffusion or pressure welding, microsections of diffused sandwiches were photographed in the unetched condition. Furthermore, etching revealed the characteristic diffusion tails caused by the in- creased diffusion rates along grain boundaries, Fig. 8 Fo~~owing50 per cold deformation compared to the slower rates within the lattice. and annealing for 8 hours at 7OOOC the diffusion This is shown in Figures 6 to 8. zone of this copper-20 per cent nickel base and platinum-5 per cent cobalt top layer contains a The confirm that the problems which zone of porosity, but this is narrower than those arise when attempting to obtain good adhesion shown in Figure 6 and 7 x 275
Platinum Metals Rev., 1987, 31, (2) 67 reduction was possible in all the cases studied. Cold rolled samples no longer show any voids and the diffusion zones are reduced in thickness to a few micrometres; barely visible under an optical microscope at x 1000 magnification. The structure of both top and base layers is that of a strongly cold worked material. The holes formed by the Kirkendall effect when a platinum-5 per cent cobaltkopper-8 per cent tin diffusion couple was annealed at 800OC are shown in Figure 6. After only 4 hours a wide band of porosity occurs. This zone is Fig. 9 Deformation ratios observed in much thinner after hours at 70o0C, and even diffused sandwiches with platinum-5 per 8 cent cobalt as the top layer on copper and less in a copper-8 per cent tidplatinum diffu- copper alloy bases, after annealing for 20 sion couple after 8 hours at 70o0C, see Figure minutes at a temperature of 7OOOC under 7. Apparently the relatively small cobalt con- 7kN pressure tent of the platinum enhances hole formation, as does an increase in annealing temperature of only IOOOC. of platinum-5 per cent cobalt to copper or The beneficial effect of nickel in the base copper-tin alloys by welding are due to ex- material is very pronounced. After only 2 hours cessive void formation in the diffusion layer, at 700OC or I hour at 800OC a platinum-5 per resulting from the Kirkendall effect. cent cobalt top layer will be separated from a The thickness of the diffusion zone after copper-10 per cent nickel base. After annealing pressing and cooling in the furnace depended a copper-20 per cent nickel/platinum-5 per cent on the system, and on the diffusion conditions. cobalt couple at 700OC for 8 hours a distinct At 700OC for 20 minutes it was between 2 and zone of voids shows up, as can be seen in Figure 9pm. During the hot welding stage the different 8, while a copper-40 per cent nickel base with metals in the diffusion couples are compressed a platinum or platinum-5 per cent cobalt top differently, depending on their hot strengths layer shows practically no hole formation after (I). The deformations observed in the diffusion annealing at 700 or 8woC for 6 and 8 hours. pairs with platinum-5 per cent cobalt as the top The growth rates of the diffusion layers bet- layer are shown in Figure 9. Because of their ween various copper-based materials and hot strength, platinum alloys deform much less platinum-5 per cent cobalt and platinum-5 per than the underlying copper alloys. This also cent iridium, after annealing 50 per cent cold may contribute to the poor adhesion observed worked samples at 700OC for 8 hours and with platinum alloys. In general the deforma- 800OC for 4 hours, are shown in Figures 10 and tion of copper-nickel alloys is similar to that of I I, respectively. In general the results are wide- the platinum and platinum-5 per cent cobalt ly scattered, due to the non-uniform formation top layers. When a pressure welded sandwich is of the layers caused by holes. Nevertheless it rolled down, a platinum-5 per cent iridium can be stated that in general copper-tin alloys alloy exhibits only 50 per cent of the deforma- exhibit the widest diffusion zones and that the tion experienced by copper-nickel alloys. A width of the zone increases with tin concentra- platinum/copper sandwich pressed at 700OC for tion. The copper-nickel alloys generally have 20 minutes with 7kN showed a 60 per cent the narrowest diffusion zones. Apparently the reduction in thickness of the copper but only 10 growth of the diffusion zone decreases at higher per cent for the platinum. After diffusion nickel concentrations; this confirms the obser- welding, cold rolling to at least 50 per cent vation that there is reduced porosity at the
Platinum Metals Rev., 1987, 31, (2) 68 Fig. 10 The diffusion zone thicknesses are shown for sandwiches of platinum-5 per cent cobalt top layers on cop- per and copper-based alloys atter cold rolling and anneal-
iy. Copper-tin base sand- 40 8 j 1 wiches have the broadest diffusion zones E a t 30- H 0 pressed =Elm$ 8OOOC 4h anneal ;20- 3 R 7OOOC 8h anneal k 10- 00 00
Fig. 11 Diffusion zone thicknesses are shown for sandwiches of platinum-5 per cent iridium on copper and copper-based alloys aRer cold rolling and annealing 0 pressed 80OOC 4h anneal 1 7OOOC 8h anneal
higher nickel concentrations. In general there is 3 x 10- I cmz/s at 700OC. These figures are less diffusion after 8 hours at 700OC than after remarkably close to the ones given elsewhere 4 hours at 800OC. for the platinum/copper system, which were The widest diffusion zone, 35pm, occurs in about 3.5x10-l' cm'ls at 850OC and the system platinum-5 per cent cobalt/copper-8 1.5x1o-~~cm~/sat 70o0C(2). per cent tin after 4 hours at 800OC. The nar- The concentration/distance curves, as deter- rowest zone was 13pm, which was observed in mined by electron microprobe analysis for copper-40 per cent nickel with platinum and copper-8 per cent tin/platinum, copper-25 per platinum alloys forming the top layer, after 8 cent nickel/platinum-5 per cent cobalt and cop- hours at 700OC. If one assumes parabolic ped6prn electroplated nickeVplatinum are growth rates according to the equation: shown in Figures 12, 13 and 14. Across the dif- X = (where X is the thickness of the dif- fusion layer the concentration gradient for fusion zone, t the annealing temperature and D copper is much flatter than that of the plati- the diffusion coefficient) then the values obtain- num, showing that copper diffuses faster into ed for D are ~XIO-" cm2/s at 8m°C and platinum or nickel than vice versa. On the other
Platinum Metals Rev., 1987, 31, (2) 69 4 Fig. 12 Shown here are the three eoncentrationldistance profiles across a diffusion zone of a pressure welded 50 per cent cold rolled platinum/copper-8 per cent tin sandwich after annealing at 8OOOC for 4 hours
Platinum Fig. 13 These are the con- centration profdes across the Nickel diffusion zone of a pressure welded platinum-5 per cent cobalt/copper-25 per cent nickel sandwich 50 per cent cold rolled after annealing at 7OOOC for 4 hours. The con- centration gradient for cop- > per is much flatter than that c- of platinum v) z WI- z
Fig. 14 The concentra- tionldistance profiles of a dif- fusion zone for a pressure welded copperleleetroplated nickel/platinum sandwich are shown after 50 per cent cold rolling and annealing at 10 prn 7OOOC for 8 hours. The dip > - in the copper curve is due to t v) the porous zone
cW -z
D
Platinum Metals Rev., 1987, 31, (2) 70 hand cobalt seems to have diffused even less during copper/nickel diffusion the well known than platinum. The irregularities on the copper Kirkendall holes form within the copper, as is curves are explained by the hole formation. shown in the dip of the copper curve on the From similar measurements made on platinum concentration/distance graph, see Figure 14. top layer diffusion couples it is concluded that platinum and also cobalt form a tin-rich -in- Conclusions termediate phase on diffusion with copper-tin Investigations of the diffusion behaviour of alloys. Apparently the cobalt “getters” some of various copper- and nickel-based components the tin away, forming a platinum-(cobalt- in contact with layers of platinum, platinum-5 copper)-tin phase faster than platinum does on per cent cobalt and platinum-5 per cent iridium its own. As yet it is not known if this platinum- have been made by various methods, and have (cobalt-copper)-tin layer is a true separate in- shown a consistent picture of pronounced diffu- termediate phase, but it will be studied later. sion of copper into platinum. This causes voids The Vickers microhardness of these ternary to form on the copper side of the interface due platinum-cobalt-tin or quarternary platinum- to the Kirkendall effect and results in adhesion (cobalt-copper)-tin phases is about 380 HV, problems. However these can be overcome by significantly higher than those of the starting using nickel as the base metal, by incorporating metals. It is surprising that this high hardness an electrodeposited nickel layer or by using a of the diffusion layer did not show up as an nickel-rich copper-nickel alloy. adhesion problem during cold rolling of the dif- fused sandwiches. Acknowledgements From the gradients of the relevant elements, We wish to thank Impala Platinum Mines Limited shown in Figure 13, platinum and cobalt seem for their support of these investigations, and Dr. A. Bischoff of W. C. Heraeus G.m.b.H. for assistance to diffuse differently, as do copper and nickel. with the microprobe investigations. Apparently there is a relationship between the changing slope of the copper and of the cobalt References curves near the top layer, since the platinum I D. Ott and Ch. J. hub, Platinum MefaLC Rev., and nickel curves show no change in the gra- 1986, 30, (3), 133 dient of their concentratioddistance curves. 2 W. Seith and T. Heumann, “Diffusion in Metallen”, 2 Edn., Springer-Verlag, Berlin, 1955 From Figure 14one can deduce that nickel and 3 A. D. Smigelskas and E. 0. Kirkendall, Trans. platinum diffuse evenly into each other. But AIME 1947, 171, 130
Hydrogen Permeability at Elevated Temperatures The study of the reactivity of minerals in Using an oxygen-buffered, double capsule fluid media under conditions of high technique, Chou has measured the permeation temperature and pressure has important im- of hydrogen through platinum, two silver- plications for their industrial utilisation. In palladium alloys, gold, and silver at a pressure such hydrothermal experiments the precious of 2 kilobar (29,000 psi, 200 MN/m*) in the metals are commonly used as containment temperature range 450 to 812OC. He showed materials; platinum and silver-palladium being that the permeabilities lie in the order: employed as semi-permeable membranes for Pd 3o Ag 7o >Pd 1o Ag 8o >F’t>Ag>Au hydrogen while gold and silver serve as The activation energies increase in this order. hydrogen barriers. To date the lack of reliable This study shows that the addition of data on the permeation rates of hydrogen has palladium to silver increases its hydrogen caused difficulties in the selection of materials permeability exponentially, and extends the and experimental conditions. data on the silver-palladium system, where the Now, however, a study by I-Ming Chou of palladium-rich alloys are used commercially as the U.S. Geological Survey has remedied this diffusion membranes for the purification of deficiency (Am. J. Sci., 1986, 286, 638-658). hydrogen. C.W.C.
Platinum Metals Rev., 1987, 31, (2) 71 A New Type of Molecular Conductor THE STRUCTURE AND PROPERTIES OF Cs[Pd(S 2C2(CN) 2)2] 0.5H20 By Professor A. E. Underhill Department of Chemistry and Institute of Molecular and Biomolecular Electronics, University College of North Wales, Bangor
A new type of two-dimensional metallic conductor, based upon a palladium dithiolene complex, has been shown to possess a novel struc- ture involving short S-S contacts in two orthogonal directions, resulting in it having metallic properties down to 4OK under high pressure. Studies of compounds of this type may lead to the development of materials for use in a chemical computer and a major programme in this area, to be known as the Molecular Electronics Research Initiative, is to be launched by the British government.
For a number of years we have been in- 125 K with clear evidence of a smeared out vestigating the synthesis, structures and pro- transition at around 240 K. Below about 125 K perties of novel molecular conductors based on the crystal behaves as a semiconductor with an square coplanar anions containing nickel, activation energy of 41 meV. Thermopower palladium and platinum. In 1981we synthesis- and magnetic susceptibility measurements also ed the first example of a one-dimensional metal indicate that the compound is a small band gap based on metal dithiolene anions, (H,0)0,33 semiconductor or semi-metal at room Lio,,[Pt(S,C,(CN) ,) I .67H, 0 (I). Over the temperature and all measurements reflect the past two years Mr. P. I. Clemenson has been in- transition at about 240 K to a low temperature vestigating the preparation of a series of semiconducting state. [M(S,Cz(CN),),]- (where M is nickel, The unusually high electrical conductivity is palladium or platinum) monoanion salts of related to the crystal structure of small cations by electrocrystallisation of solu- [Cs(S,C,(CN),), ].o.gH,O. This is shown in tions containing the dianion salt. This has led to the figure and is quite different from any the discovery of compounds exhibiting novel structure previously reported for a magnetic or electronic properties (2). Using [M(S,C,(CN),),]- monoanion salt (3). The solutions of Cs,[Pd(S,C,(CN),),I he observed structure contains [Pd(S,C2(CN),),l,2- the formation of small plate-like black crystals dimers in an eclipsed configuration with intra of Cs[Pd(S, C, (CN) ,) ,1 -o.gH,0 growing on Pd-Pd distances of 3.329(5) di. The occurrence the platinum anode. Whereas the monoanion of the monoanions as dimer pairs is consistent
"i(Sz Cz (CN) 2) z I- and [WSz Cz (CN) 2) 2 1 - with the single negative charge on the anion salts of Group I cations behave as semiconduc- which will result in a single unpaired electron in tors at room temperature with conductivities of the highest occupied molecular orbital of the Platinum Metals Rev., 1987, 31, (2), 72-73 72 ambient pressure at 240 K is suppressed and at the highest pressure studied (12. I kbar) the crystals remain metallic down to 40 K. Below 40 K at this pressure, the resistance rise with temperature is relatively small and the conduc- tivity at 1.4 K was found to be above 10 Skm. The effect of pressure is to squeeze the dimer monoanion pairs closer together and therefore to increase the extent of the S-S interactions. It has already been shown in organic metals that the effect of pressure is to stabilise the metallic state down to low temperatures and indeed in some instances a superconducting state may be achieved at very low temperatures. Cs[Pd(S,C,(CN),),l.o.~H,Ois a new type of molecular metal because it is a stoichiometric .- metal complex with a two dimensional conduc- ting network as distinct from the previously prepared molecular conductors based on non- integral oxidation state complexes with an essentially one-dimensional conduction In this b-axis projection of the crystal pathway. structure of Cs[Pd(S zCz(CN),),] - 0.5H20 the short S-S contacts are indicated by References broken lines. The molecular structure of I A. E. Underhill and Munir M. Ahrnad, 3. Chem. [Pd(SzC,(CN),)z]- is also shown SOC.,Chem. Commun., 1981, 67 2 P. I. Clernenson, A. E. Underhill, M. B. Hursthouse, R. L. Short, G. J. Ashwell, I. M. Sandy, M. T. Jones, C. Jacobsen and K. the c and a directions. This gives rise to a 2-D Carneiro, Synth. Met., 1986, 19, 579 sheet structure in the ac plane, the sheets being 3 M. B. Hursthouse, R. L. Short, P. I. Clernenson and A. E. Underhill, 3. Chem. SOC., Dalton separated in the b direction by the caesium ions Trans., submitted for publication and water molecules. The large surfaces of the 4 I. D. Parker, R. H. Friend, P. I. Clernenson and plate shaped crystals correspond to the ac plane A. E. Underhill, Nature, 1986, 324, (6097), 547 of the structure and measurements of the anisotropy of conduction show that the most More Organometallic Compounds conducting direction is in the a direction with The three volume Dictionary of Organometallic Compounds and the first sup- an anisotropy of less than 10. Thus the elec- plementary volume, published by Chapman trical conduction properties and structure show and Hall, have been reviewed here during the the compound to be a two-dimensional conduc- past eighteen months. These have now been tor as distinct from the previously prepared followed by the Second Supplement, again one-dimensional metals based square edited by Dr. Jane E. Macintyre, running to on over 600 pages and priced at E145. A further coplanar complexes. 3 I 5 compounds of the platinum metals are in- The pressure dependence of the conductivity cluded, all with their molecular formulae, CAS of the compound has been studied by Dr. registry number and literature reference. As Richard Friend and Mr. Ian Parker at the before, the editor has had the cooperation of a Cavendish Laboratory at the University of distinguished international advisory board and of a number of specialised editors for individual Cambridge (4). They have shown that under metals, while sources of further information are pressure the crystals behave as metals, that given in a substantial list of original publica- above 7 kbar pressure the transition observed at tions covering the period up to mid-1985. Platinum Metals Rev., 1987, 31, (2) 73 Some Ternary and Higher Order Platinum Group Metal Alloys A PRELIMINARY REVIEW AND ASSESSMENT OF THEIR CONSTITUTION AND PROPERTIES By I. R. McGill Johnson Matthey Technology Centre Platinum-based alloys find many applications in both high and low temperature industrial environments and are particularly suited to operation under corrosive aqueous and high temperature gaseous condi- tions. A wide variety of alloys exist which have been specifically designed for these purposes and in many cases they contain one or more non- platinum group metal. Although this situation is quite acceptable, there remains a fundamental need for systematic investigation of the basic pro- perties and constitution of platinum group metal alloys. Such a founda- tion in materials technology generally leads to an understanding of materials behaviour and provides guidance in designing new alloys with improved properties for existing and future applications. This review features the work which has been done on ternary and higher order platinum group metal alloys and provides access to important data. In July 1857 a patent was granted to Jules By the mid-19th century it had been Henry Debray for “Improvements in the recognised that the properties of platinum Manufacture or Reduction of Platinum” (I), could be improved by selective alloying with and the English rights of this important patent other platinum group elements, so extending were immediately purchased by George the already growing industrial applications of Matthey. It was claimed within his specification platinum. that the method developed for processing The constitution and properties of binary platinum ores was of particular advantage, in alloys of the platinum group metals have been that alloys of platinum and the different metals thoroughly investigated and equilibrium phase found within its ores were produced which diagrams exist on all but a few systems. possessed properties more advantageous than However, little has been done to characterise pure platinum. Indeed, in 1859, H. Sainte- the 20 possible ternary systems. Published in- Claire Deville and J. H. Debray declared that formation which is available on these systems is they had solved the problem of preparing a highlighted in Table I by a blue tint, while the platinum-iridium-rhodium ternary alloy with type of data available on both these ternary and excellent ductility for fabrication (2). The higher order systems is presented with weight percentages of rhodium and iridium references to the literature in Table 11. Clearly, specified by Deville and Debray were 5 and the platinum-palladium-rhodium system has 19.6, respectively. The constitution of the received the most detailed investigation platinum-rhodium-iridium system has not been primarily because of the major industrial im- well established and only recently has there been portance of binary platinum-rhodium alloys, any attempt to characterise the structure and pro- for example, in catalysis and as a constructional perties of selected ternary alloys (3). material for glass processing equipment. The Platinum Metals Rev., 1987, 31, (2), 74-90 74 UK ISSN 0032-1400 PLATINUM METALS REVIEW A quarterly survey of research on the platinum metals and of developments in their applications in industry VOL. 20 APRIL 1976 NO. 2 Contents Sulphate Emissions from Automobile Exhaust 38 Palladium Alloys for Electrical Contacts 44 Coating Methods for Use with the Platinum Metals 48 Russian Research on the Platinum Group Metals 53 Hydrogen in Palladium 54 Carboxylato Complexes of the Platinum Group Metals 54 Abstracts 64 New Patents 69 Communications should be addrmsed to The Editor, Pkrtinum M& R&w Johnson Matthey & Co Limited, Hatton Garden, London EClN 8EE T.M.bleI1 ii System References and Data Type resistancc tensile1 solubility {(TI rupture tensik constitutm as test gas or rupture electncal of tensile stress including 1creep:stress ambent lrom resistance propertes area characteristics Imp coefficant limlt in elastlcity propertes impunties of EMF shock strength at rupture of characteristics Reductm Mineralogy Corroston Ternary andlor diagram phase Density Thermal ReslStNlty Thermal Creep Temperature lensile %Elongatton % StIeSs RopomnaI Effect Hardnesslmicrohardns Modulus System Reference 4 5 6 7 8 9 10 Pt-Pd-Rh 11 12 13 14 15 16 17 3 Pd-Rh-RU -4 -5 -18 F+t-lr-Ru -19 -20 -19 Pt-Pd-Ru -2 -21 Ir-Ru-0s -22 -23 Pt-Rh-RU -19 20 Pt-Pd-lrPd-Rh-lr 3 Ir-Pt-0s 3 PI-Rh-lr 24 Pt-Rh-lr 2 Pt-Rh-Pd-RuPt-Rh-Pd-RU 133 Pt-Rh-lr-Ru 3 R-Rh-Pd-lr 15 Platinum Metals Rev., 1987, 31, (2) 76 UK ISSN 0032-1400 PLATINUM METALS REVIEW A quarterly survey of research on the platinum metals and of developments in their applications in industry VOL. 20 APRIL 1976 NO. 2 Contents Sulphate Emissions from Automobile Exhaust 38 Palladium Alloys for Electrical Contacts 44 Coating Methods for Use with the Platinum Metals 48 Russian Research on the Platinum Group Metals 53 Hydrogen in Palladium 54 Carboxylato Complexes of the Platinum Group Metals 54 Abstracts 64 New Patents 69 Communications should be addrmsed to The Editor, Pkrtinum M& R&w Johnson Matthey & Co Limited, Hatton Garden, London EClN 8EE UK ISSN 0032-1400 PLATINUM METALS REVIEW A quarterly survey of research on the platinum metals and of developments in their applications in industry VOL. 20 APRIL 1976 NO. 2 Contents Sulphate Emissions from Automobile Exhaust 38 Palladium Alloys for Electrical Contacts 44 Coating Methods for Use with the Platinum Metals 48 Russian Research on the Platinum Group Metals 53 Hydrogen in Palladium 54 Carboxylato Complexes of the Platinum Group Metals 54 Abstracts 64 New Patents 69 Communications should be addrmsed to The Editor, Pkrtinum M& R&w Johnson Matthey & Co Limited, Hatton Garden, London EClN 8EE Fig. 3 100 hour etreee rupture and tensile characterietice of eelected alloye in the 40 platinum(pa1ladium)-10 rhodium eyetem, aner Ref. 6. Tensile aa etrength data were obtained ue- 4 ing 1.5 mm diameter wire teet 30 ;;- piecee annealed for 15 minutes I at 1000°C in air prior to teet. s The loading rate woe 10 mm/min W 20 with a gauge length of 50 mm Lo W 2 v)z 10 F density of such alloys by the addition of alloy. Figure 3 highlights the effect of palladium. palladium substitution for platinum in the Excellent reviews of this subject have been pseudo-binary system platinum(palladium)-Io published (I I, 25). Although palladium can be rhodium on both the tensile and 100 hour rup- added safely to 5 weight per cent rhodium- ture stress of alloys at temperatures of 1200 and platinum alloy without loss of high temperature 1400OC. strength, and with a slight improvement in duc- From mechanical property data reported by tility at temperatures up to 1250°C, further Rytvin, Kuz'min and Petrova (8) on a selection substitution for platinum causes a degradation of platinum-rhodium-palladiumalloys tested at of properties with respect to the parent binary temperatures of I 100 to 1400OC, Figure 4, it is Fig. 4 The high temperature tenaile strength of rhodium wae interpolated from data presented in Ref. 30. The data for platinum, pdadium and the two ternary dloye were taken from Ref. 8. Wire ramplee 1.3 mm in diameter were annealed for 3 how at 130OOC and then teeted with a loading rate of 6 mmlmin Platinum Metals Rev., 1987, 31, (2) 79 I Fig. 5 Elongation data have been taken from Ref. 8 and were obtained over a 50 mm gauge length. Pre-tert conditionr and loading rate were ar dercribed in Figure 4 Fig. 6 Elongation valuer for doyr containing 20 weight per cent rhodium and for the doywith 50 weight per cent platinum were obtained using a 50 mm gauge length. Elongation valuer for the remaining aUoyr were obtained over a 30 mm ewelength(10) recommended that palladium-rhodium and I2.75Mh (10). These differences reflect the platinum-palladium-rhodiumalloys be used for variation in pre-test annealing conditions and high temperature applications. The tensile pro- test sample geometries. Per cent tensile elonga- perties of 20, 10, 15 and 7 weight per cent tions at fracture for a number of ternary alloys rhodium-platinum binary alloys, however, still have been reported (8, IO), and are shown in exceed those of any other alloy investigated. Figures 5 and 6. Again there is a striking dif- Rytvin and colleagues report tensile strength ference in the values of elongation values for the platinum70 palladium-Iorhodium at fracture for the platinum-70 palladium- alloy at 1200 and 1400OC to be 22.56 10 rhodium alloy. It is reported that the and 5.88MPa7 respectively. Reinacher, platinum-70 palladium-Io rhodium alloy fails in however, reports respective values of 28.24 and an intercrystalline manner at 140o0C, but with Platinum Metals Rev., 1987, 31, (2) 80 Fig. 7 Data have been taken from Ref. 10, with pre-teat rample conditioning and teneile test eonditionr ae described in Fb3 an elongation at fracture equivalent to that of Values of the per cent reduction in area after pure platinum (10). tensile test give some indication of this effect Perhaps the most important observation and are- shown in Figure 7, after (10). An ex- made on the high temperature tensile proper- planation of this behaviour and an interpreta- ties of the platinum-palladium-rhodium alloys tion of the data has been given (I I). with palladium contents between 40 and 70 weight per cent, and rhodium contents between Creep and Streee Rupture Properties 10and 20 weight per cent, is the low ductilities The stress rupture characteristics of alloys in shown by these alloys between goo and I IOOOC. the platinum-palladium-rhodium system, with Fig. 8 100 hour etresr rupture data have been compiled from Ref. 7 and Ref. 10. The materials teeted at 900,1250 and 150OOC (7) were pre-conditioned for 60 min at 9OO0C, 30 min at 120OOC and 10 min at 150OOC in air, rerpectively. The other three were pre-conditioned for 15 min at 140OOC in air (10) Platinum Metals Rev., 1987, 31, (2) 81 rhodium contents up to 20 weight per cent have A comparison between the 100 hour stress to been thoroughly investigated (7, 10, 16) and rupture properties of example materials from previously reviewed (I I, 25). There is no doubt each of these categories can be seen in Figure 8, that the high temperature performance of (7, 10). Figures 9 and 10 present 100 hour platinum-rhodium binary alloys containing up stress rupture data on selected binary alloys, to 20 weight per cent rhodium exceeds that of and pure elements for reference. any ternary alloy examined to date. Ternary At temperatures up to 125ooC,the properties alloys which have been investigated fall into of low-palladium ternary alloys, Figure 8, com- two catagories; (i) alloys with a combined pare favourably with binary platinum alloys rhodium and palladium content not exceeding containing up to 5 weight per cent rhodium, 20 weight per cent, and, (ii) alloys containing Figure 9. A slight improvement in ductility has between 40 and 70 weight per cent palladium. also been observed. Fig. 9 100 hour etreee rupture data presented here have been compiled from Re&. 30, 32 and 33 Fig. 10 100 hour etrese rupture data for these five binary elloye have been com- piled from Refe. 30 and 33 Platinum Metals Rev., 1987, 31, (2) 82 Fig. 11 Theae 100 hour rupture f-8 have 'been compiled from Ref. 7 Fig. 12 Theae figurer of the 100 hour atreaa-rupture propertiea of platinum-5 rhodium-palladium doyr have been compiled from Ref. 7 Fq. 13 Data for the atreaa-rupture propertiea of platinum-3 palladium-7 rhodium have been compiled from Ref. 7 Platinum Metals Rev., 1987, 31, (2) 83 Fig. 14 Stress-rupture properties, at 1200°C, of four high palladium ternary alloys have been compiled from Refs. 10 and 16 Fig. 15 These data have been compiled from Ref. 10, the stress-rupture proper- ties being determined at 140OOC At temperatures between 1250 and 150o0C, temperatures between 900 and I 5m°C is shown alloys containing less than 5 weight per cent in Figure 12. palladium and with rhodium contents below 10 The results of investigations on ternary weight per cent show an increase in strain com- platinum-palladium-rhodium alloy pared to the binary alloys platinum-5 rhodium replacements for the most commonly used and platinum-Io rhodium, Figure 11. An in- platinum-rhodium binary alloy, that is crease in the palladium content to 10weight per platinum-Io rhodium, have lead to the develop- cent, however, decreases rupture strain and ment of a compromise alloy, namely marginally reduces rupture strength (7). The platinum-3 palladium-7 rhodium. The stress effect of palladium on the IOO hour rupture rupture properties of this particular alloy are stress of a platinum-5 rhodium alloy at presented in Figure 13 and, by reference to Platinum Metals Rev., 1987, 31, (2) 84 Figure 9, it is only at operational temperatures rate against calculated values was found. The of I 500OC that the material shows inferior pro- experimental creep rate data from this work perties to that of platinum-ro rhodium. An un- have been reproduced in Figure 16. fortunate consequence of using palladium as an The effects of alloying platinum with alloying additive to binary platinum-rhodium palladium, rhodium, iridium and ruthenium on alloys is the tendency of most materials to fail the formation of dislocation structures in binary by intercrystalline cracking at intermediate alloys has been investigated by Usikov, temperatures between 850 and 10ooOC. The Stepanova and Rytvin (17)~and highlights the lack of ductility in this temperature regime resulting effect on creep rate, Figure I 7. Clear- restricts their use to low stress applications. ly, palladium additions to platinum up to 10 As far as the high palladium alloys are con- weight per cent have virtually no effect on the cerned, results on the stress rupture stacking fault energy of platinum, with the characteristics of selected materials obtained by result that there is little difference between the Reinacher would suggest that the creep properties of these materials. The effec- platinum-40 palladium- 10 rhodium alloy has tiveness of other platinum group metals in adequate strength properties for industrial ap- reducing the stacking fault energy of the plications where the operating temperature platinum solvent and thereby improving high does not exceed 120o0C (10, 16). Figures 14 temperature creep properties was found to be and I 5 compare the stress rupture properties of ruthenium>iridium>rhodium>palladium. high palladium ternary alloys at 1200 and This behaviour is undoubtedly reflected in ter- I 50o0C, respectively. nary and higher order alloys and clearly offers An attempt to correlate the high temperature the opportunity for developing new alternative creep properties of a selection of platinum- heat resistant alloys. palladium-rhodium alloys with palladium and rhodium concentration has been reported (9). Electrical Resistance and Thermal EMF Reasonable agreement between experimentally The electrical resistance and temperature determined values for rupture life and creep coefficient of resistance of a complete range of Fig. 16 Creep rater were determined on wire rampler of 0.8 mm diameter, with a gauge length of 50 mm and an npplied rtrerr of 4.83 MPa. Prior annenling war carried out at 1350 and 1425OC for 3 hourr. Experimentd valuer reported were used to ertablirh time-to-failure and creep rate equationr nr functionr of palladium nnd rhodium doy content (9) Platinum Metals Rev., 1987, 31, (2) 85 alloys in the platinum-palladium-rhodium temperature range, and are presented in the system have been measured and reported (6). form of pseudo-binary sections and a constant Iso-resistance plots at 25OC are provided thermal e.m.f. contour map. Thermal e.m.f. together with a similar graphic presentation for results are consistent with the view that the the temperature coefficient of resistance. The platinum-palladium-rhodium ternary system hghest electrical resistance and lowest shows complete solid solubility. temperature coefficient of resistance is shown by an alloy platinum-so palladium-30 rhodium. Environmental Propertiee Thermal e.m.f. values for alloys containing up The effect of thermal cycling on the creep to 10weight per cent rhodium against platinum ductility of platinum-rhodium, platinum- were determined for the 100 to 10ooOC palladium-rhodium and platinum&ladium- ~~~ ~ ~ ~ ~~~~~~~~~~ ~~~~ ~ la#. IV Room Temperature Tensile Data for Platinum-Palladium-RhodiumAlloys I with Rhodium Contenti of 5. 10 and 20 weight". Der cent Alloy (wt. %I Tensile strength Young's modulus Normalised tensile strength G o (MPe) E x lo-' (MPa) olE x 10' 95 - 5 225.5 194.2 1.16 ~ 90 5 5 264.8 186.3 1.42 ' 85 10 5 274.8 180.5 1.52 80 15 5 304.8 176.5 1.72 75 20 5 362.8 170.6 2.13 70 25 5 324.9 168.7 1.93 60 35 5 332.4 162.8 2.04 50 45 5 329.8 158.9 2.07 40 55 5 309.8 156.9 1.97 30 65 5 309.8 149.1 2.07 20 75 5 284.9 147.1 1.94 10 85 5 257.3 145.1 1.77 5 90 5 243.6 141.2 1.73 - 95 5 284 133.4 2.13 90 - 10 323.6 211.8 1.53 80 10 10 374.6 200 1.87 70 20 10 412.5 186.3 2.2 60 30 10 406 174.6 2.33 50 40 10 406 166.7 2.43 40 50 10 360 160.8 2.23 30 60 10 357 157.8 2.26 20 70 10 330.5 153 2.16 10 80 10 281.1 151 1.86 - 90 10 372.6 149 2.5 80 - 20 416.8 237.4 1.76 70 10 20 443.9 225.5 1.97 60 20 20 462.2 21 5.7 2.14 50 30 20 512.2 206 2.49 40 40 20 568.4 196 2.9 30 50 20 562.1 190.3 2.95 20 60 20 487.2 184.4 2.64 - 80 20 500.2 172.6 2.9 Platinum Metals Rev., 1987, 31, (2) 86 Fig. 17 Test samples in sheet form were annealed for 2 hours at 90 per cent of the melting point, cold-rolled to 0.5 mm sheet (6 per cent reduction) and cut to 3 mm discs for experimental work to determine the potency of the second ele- ment on the creep properties (17) rhodium-ruthenium alloys has been studied by of cycles required to achieve a crack length of Medovoi and Rytvin (13). Sheet samples of I mm was used as an indication of thermal alloy were held between ceramic plates and shock resistance. Ductility was determined heated by electrical resistance. The thermal cy- from the creep time at 140o0C with an initial cle was between 1400 and I~~OOC,with a full stress of 4.9 MPa. The results of this investiga- cycle lasting 30 seconds. Time spent at the tion are presented in Figure 18. The binary lowest temperature was 5 seconds. The number platinum-rhodium alloys and also the Fig. 18 To determine resistance to thermal shock, samples were cycled between 1350 and 14OOOC. Tests were carried out on vacuum melted materials, forged at 1100 to 150OOC and rolled to 0.5 mm thickness (40per cent reduction). Sam- ple dimensions were 60~10~0.5 mm with a central hole serving as a stress con- centrator. AU the samples were annealed at 145OOC for 2 hours prior to test (13) Platinum Metals Rev., 1987, 31, (2) 87 Fig. 19 Irothermal rectionr at 140OOC are given for variour platinum group I metal ternary ryrtemr, &er Refr. 3 and 19 platinum-15palladium-5 rhodium alloy had the was that alloying elements which cause a reduc- highest thermal shock resistance of all the alloys tion in grain size and creep ductility of tested. The basic conclusion from this work platinum alloys also lower the resistance to Platinum Metals Rev., 1987, 31, (2) 88 thermal shock in the range 1350 to 1400OC. ruthenium alloy which is similar to that observ- In 1975, Stepanov, Chernyshova and ed in the binary platinum-20 iridium alloy. The Shevelev reported on the behaviour of a internal oxidation of ruthenium may be the platinum-I 5 palladium-5 rhodium alloy and cause of such behaviour, resulting in an oxide two binary palladium-rhodium alloys during dispersion strengthened material. standard welding operations (14). It is clear The 1400OC isothermal cross-section of the from this investigation that an alloy containing palladium-rhodium-ruthenium phase diagram palladium is more prone to weld crack forma- has been reported by Raevskaya, Vasekin and tion than platinum-rhodium binary alloys. The Sokolova (3), indicating the existence of a two effects of micro-impurities on weld crack for- phase region based upon the binary solid solu- mation were also investigated. The presence of tion of platinum-rhodium and the ternary ter- silicon, calcium and aluminium was found to minal solid solution of ruthenium. Isothermal exacerbate the cracking phenomenon in all cross-sections at 140ooC for the ternary systems alloys investigated. iridium-rhodium-ruthenium, platinum- Not only does the presence of metallic im- palladium-iridium and palladium-rhodium- purities affect the properties of platinum group iridium are also presented. From microstruc- metal alloys but gaseous impurities can tural and X-ray analyses it was shown that a significantly alter in-service behaviour. complete series of ternary solid solutions were Kalinyuk and Solomentsev have investigated present in the platinum-rhodium-iridium and techniques for the determination of gaseous im- platinum-rhodium-palladium systems at purities in noble metal alloys (I 5). Oxygen and 1400°C, and that the miscibility gaps in the hydrogen determinations are presented for palladium-iridium-platinum(rh0dium)systems platinum and platinum-rhodium, platinum- were due to decomposition of the solid solution palladium-rhodium and platinum-palladium- in the palladium-iridium system at 148oOC rhodium-iridium alloys. However, no alloy (27). compositions are given as comparative analysis Hardness variations are also presented as a techniques were being evaluated. function of alloy composition in the palladium- iridium-rhodium and rhodium-ruthenium- Other Ternary and Higher palladium systems, and are used to confim the Order Systems position of phase boundaries. Some indication The mechanical properties of two palladium of the constitution of the platinum-ruthenium- alloys containing rhodium and ruthenium, rhodium-palladium(iridium) quaternary palladium-I rhodium-4 ruthenium and also systems has been provided based upon electron palladium-3 rhodium-2 ruthenium, have been probe microanalysis, hardness and lattice cell reported by Wise and Eash (4, 5). Ruthenium volume changes of selected experimental alloys. is shown to be extremely effective in hardening Similar constitutionalwork on the ruthenium- palladium and increases the annealing platinum-rhodium(palladium)(iridium) ternary temperature from 80o/90o0C to 1ooo/110o~C. systems has been reported by Raevskaya, The tensile strength of palladium-I rhodium- Vasekin, Konobas and Chemleva (19). 4 ruthenium in the fully annealed state is ap- A schematic presentation of the ternary phase proximately 90 per cent greater than that of diagrams at 140oOC is shown in Figure 19, after palladium. An increase of 42 per cent is shown (3) and (19). for the palladium-3 rhodium-2 ruthenium alloy. In attempting to define optimum composi- Both alloys exhibit reductions in cross-sectional tions in complex alloyed platinum alloys for use area of greater than 84 per cent in either the an- in heat resistant applications, Norvik, Rytvin, nealed or as-received condition. These authors Medovoi and Ulybysheva examined statistically also report a precipitation hardening effect at a range of alloys in the platinum-palladium- annealing temperatures of 800°C for the high rhodium-gold-iridium system (34). The results Platinum Metak Rev., 1987, 31, (2) 89 of creep rupture tests carried out at 1400OC then the effect of gold on the stress rupture pro- would initially indicate that a platinum perties of platinum-palladium-rhodiumalloys is alloy of nominal composition, platinum-Io quite remarkable, Figure I 5, as the rupture life palladium-Io rhodium, with 0.1 weight per quoted by Reinacher for the platinum-6o cent of gold and iridium was a suitable can- palladium-Io rhodium alloy was 1.25h (10). didate for further development. This particular alloy tested at 1400OC under an applied load of Conclusions 4.9MPa, demonstrated a rupture life capability Considering the importance of the platinum of 77 hours which is indeed comparable with group metals in many high temperature in- the properties of platinum-40 palladium-20 dustrial applications, it is surprising that there rhodium, Figure I 5, and platinum-10 rhodium. has been only limited systematic study of the It was also clearly demonstrated that time-to- constitutional characteristics and properties of failure increased with a decrease in the ternary and higher order systems. What is palladium content and an increase in the available in the literature has provided impor- rhodium and gold contents. The need for an tant guidelines for those involved in the iridium content of 0.1 per cent was stressed. engineering development of platinum group Further work identified an alloy, platinum-6o metal products. Clearly there is a need for fur- palladium-Io rhodium containing 0. I per cent ther studies of these systems which may result gold, and excluding iridium, which had a rup- in the development of additional alloys suitable ture life of 60 hours. If this is indeed the case, for use in aggressive environments. References I British Patent 1947; 1857 19 M. V. Raevskaya, V. V. Vasekin, U. I. Konobas and T. A. Chemleva, Vesm. Mosk. Univ., Ser. Sainte-Claire Deville and J. H. Debray, Ann. 2 H. Khim., 1984,25, (I) Chim. Phys., 1859,56, 385 20 V. V. Vasekin, M. V. Raevskaya and E. I. 3 M. V. Raevskaya, V. V. Vasekin and I. G. Rytvin, “Summary of Reports to the 4th AU Sokolova, J. Less-Common Met., 1984,99, 137 Union Meet. on Constitution Diagrams of 4 E. M. Wiseand J. T. Eash, TramAIME, 1935, Metallic Systems”, ed. N. V. Ageev, Nauka, 179 313 Moscow, 1982,p. 77 5 E. M. Wise and J. T. Eash, Trans.AIME, 1938, 21 R. S. Polyakova, Thesis, “Phase Diagram of 128, 282 Systems Pd-Ru and Pt-Pd-Ru”, Inst. Met., 6 W. A. Nemilov, A. A. Rudnitski and R. C. Polya- Akad. Nauk SSSR, 1956 kova, lev. Sekt. Platiny, 1951,26, 16 22 L. J. Cubri, Miner. Sci. Eng., 1972,4, (3), 3 7 G. Reinacher, Metall, 1962, 16, (7), 662 23 S. A. Toma, Thesis, “Mineralogical Studies on 8 E. I. Rytvin, V. M. Kuz’min and A. E. Petrova, Some Synthetic Alloys and Minerals of the Metalloved. Term. Obrab. Met., 1967, (4), 58 Platinoid Group”, Aston University, U.K., 1975 9 I. E. Rytvin, V. M. Kuz’min and Yu. V. Meitin, 24 S. A. Toma and S. Murphy, Can. Mineral., 1977, Metalloved. Term. Obrab. Met., 1969,(2), 71 15, 59 10 G. Reinacher, Metall, 1971,25, (7), 740 25 A. S. Darling, Platinum Metals Rev., I 962,6,(4), 148 11 A. S. Darling, Platinum Metals Rev., 1973, 17, 26 A.S.Darling,Platinum Metak Rev., 1961,5,(2),58 (41, 130 27 E. Raub, J. Less-Common Met., 1959, I, 3 12 French Patent 2,135,445;1971 28 E. Raub, H. Beeskow and D. Menzel, Z. 13 L. A. Medovoi and E. I. Rytvin, Metalloved. Metallkd., 1959,50, (71, 428 Term. Obrab. Met., 1974,(8), 76 29 A. A. Rudnitskii, R. S. Polyakova and I. I. 14 V. V. Stepanov, T. A. Chernyshova and V. V. Tyurin, Im. Sekt. Platiny, 1955,29, 19 Shevelev, Fiz. Met. Metalhed., 1975, 39, (I), 30 “Edelmetall-Taschenbuch”, Degussa, Frankfurt 183 a M., 1967 15 N. N. Kalinyuk and A. N. Solomentsev, Zavod. 31 W. Koster, Z. Metallkd., 1948,39, (I),I Lab., 1976,42, (31, 271 32 G. Reinacher, Z. Metallkd., 1962,53, (7), 444 16 G. Reinacher, Metall, 1973,27, (7), 659 33 G. Reinacher, Metall, 1961,15, (7), 657 17 M. P. Usikov, G. S. Stepanova and E. I. Rytvin, 34 F. S. Novik, E. I. Rytvin, L. A. Medovoi and L. Russ. Metall., 1981,(5), 114 P. Ulybysheva, Sou. Non-Fern Met. Res., 18 J. G. Want, Platinum MetalsRev., 1961,5,(2), 42 1980,8, (31, 298 Platinum Metals Rev., 1987, 31, (2) 90 Platinum and Palladium in Astronomy and Navigation THE PIONEER WORK OF EDWARD TROUGHTON AND WILLIAM HYDE WOLLASTON By John A. Chaldecott The Science Museum, London Astronomy and navigation depend to a large extent on the ability to measure angular displacements with a high degree of accuracy, and since early times instrument makers have sought to improve the usefulness of their products by innovation. Shortly after ingots of malleable platinum and palladium became available commercially in England it was realised that these new metals had properties which were superior to those of silver, upon which the scales used for measuring angles were then engraved. The use made of platinum and palladium by one Londonfirm of instrument makers in thefirst half of the nineteenth century is considered here. The platinum that came to be used by makers One of the names applied in the gold mines of scientific instruments early in the 19th cen- of the Spanish West Indies to these white tury had its origin in one of the Spanish col- onies in South America, the Viceroyalty of New Granada. It occurred there as white metallic grains mixed with black magnetic sand and grains of gold, in alluvial deposits in the Chocd district of what is now the Republic of Colom- bia. The grains of both metals were rounded and of approximately the same size, the propor- tion of platinum present varying in different localities from one to four or even more ounces per pound of gold. Grains of gold and those containing platinum were recovered together from alluvial deposits by washing, and the two kinds were then separated from each other by hand sorting, grain by grain. Any gold which still remained associated with platinum was then removed by amalgamation with mercury. No practical use was found during the greater part of the 18th century for these white metallic grains which, William Hyde Wollaeton on the orders of the Spanish Government, were 1766-1828 thrown into the Bogota river, that method of A sketch made by Francis Chantrey R.A., using disposal being intended to prevent fraud which the camera lucida. The device was invented by Wollaston in 1807 and soon came to be used might otherwise occur by melting platinum- widely as an aid to drawing containing grains with gold (I). Repmduced by muncsy of ihc Tmsta of the Scirnce Muscum Platinum Metals Rev., 1987, 31, (2), 91-100 91 metallic grains was “platina” and the name was enough to be marketed commercially. The accepted into the English language when method he used was kept a closely guarded samples were made available from Spain to in- secret and was not divulged by him until short- terested persons in Europe. In the year 1777, ly before his death in 1828 (6). In brief, it con- by which time European scientists believed that sisted in adding ammonium chloride to the platina was a distinct metal, a Swedish chemist solution obtained by dissolving platina in aqua Torbern Bergman proposed that platina should regia, thereby precipitating the platinum as be renamed platinum (2). chloroplatinate. Spongy metallic platinum was There appears to have been little support then obtained by carefully heating the then for such a change of nomenclature, and it precipitate, and it was then consolidated by was not until early in the 19th century, when compression, heating, and forging, to produce true platinum metal had been isolated from an ingot of malleable platinum. platina by chemical means, that the word Approximately three quarters of Wollaston’s platinum came to assume its current meaning. total output of malleable platinum was For some unknown reason several important marketed for him commercially by William British makers of scientific instruments still Cary (1759-1829, a mathematical instrument continued to use the word platina in preference maker in the Strand, London (7). Some idea of to platinum until well into the 1840s~as will the size of ingot that Wollaston was able to pro- presently be made clear. duce in those early days is to be seen in Wollaston’s register of ingots sent to Cary, The Isolation of Platinum where one is noted as weighing just over 33 and Palladium ounces troy (8). Ever since the 1750s chemists had been aware that grains of pure platina were in some small Troughton’s Association degree malleable, yet they could not be brought with Wollaston into fusion by the greatest heat attainable in or- Edward Troughton was the foremost maker dinary furnaces. The problem was finally of scientific instruments in Britain during the resolved in a different manner during the first first quarter of the 19th century. He made con- few years of the 19th century, when an informal siderable improvements in many types of in- partnership of two English chemists applied struments used in astronomy, navigation and themselves to an analysis of crude platina. geodetic survey, and such was the excellence of At that time it was common knowledge that his work that there was a great demand for his when platina was dissolved in aqua regia there products from many parts of the world. In I 826 was always left a black insoluble residue. The Troughton took as his partner another and partners decided that one of them, William younger London instrument maker, William Hyde Wollaston, should investigate the soluble Simms (1793-1860), the name of the firm then portion, leaving the other partner, Smithson being changed to Troughton & Simms (9). Tennant (1761-ISIS), to concentrate his atten- After the death of Troughton ten years later, tion on the insoluble residue. The mutual divi- the business was carried on by Simms, and the sion of effort culminated in Wollaston name of the firm remained unaltered until 1922 discovering the presence of two new metals: when, following a merger, the firm became palladium in 1802 (3) and rhodium in 1804 (4). known as Cooke, Troughton and Simms. Tennant’s discovery of another two new One of the most important improvements metals, iridium and osmium, was announced in Troughton introduced was a new method of 1804 (5). dividing the arcs of astronomical and some By the end of 1804 Wollaston had succeeded other instruments; this was first used by him in in isolating platinum by chemical means and in 1785, and after he had given a description of the producing ingots of malleable metal large method to the Royal Society of London in Platinum Metals Rev., 1987, 31, (2) 92 1809, the Society awarded him its Copley Medal (10). Prior to Wollaston's isolation of platinum and palladium, instrument makers usually engraved the angular scales of sextants and similar in- struments on a thin strip of silver laid in a groove cut in the brass frame to receive it. Silver has the unfortunate property of tar- nishing and, if not cleaned, will eventually turn black in colour. However, repeated rubbing gradually wears away the silver, which is fairly soft, and in time the incised divisions become less and less distinct and may eventually be lost altogether. The alternative was to use a strip of gold, which does not tarnish but is far more ex- pensive. When Wollaston's malleable platinum became available Troughton realised that the Edward Troughton metal had properties that would make it more ca. 1753-1836 suitable than silver for use as an inlay on which This marble bust of Troughton costing El05 was to engrave the angular scale of a sextant. It subscribed for by his friends and executed in 1825 by Francis Chantrey R.A. At Troughton's could take a fine polish, had a silvery ap- request it was placed in the Royal Observatory at pearance but did not tarnish, was dearer than Greenwich in 1834 silver but cheaper than gold, and was harder Reproduced by counny of the Royal Gmnwich Obocrvstory than both those metals (11). Wollaston's record of his own income derived period from 1810 to 1820inclusive (see Table), from chemical activities shows that in the year the final delivery being made only a few months 1806 he supplied Troughton direct rather than before Wollaston gave up his refining process through Cary with 48 oz 8 dwt of malleable owing to the difficulty of obtaining supplies of platinum, at a cost of 15s. an ounce (12). Fur- crude platina from South America (13). ther supplies were obtained at intervals over the From an invoice preserved in Wollaston's Wollaston's Sales of Malleable Platinum to Troughton Date Troy Weight cost supplied oz dwt gr 1 fsd 8 Mar 1806 48 8 0 36 6 0 14 Jul 1810 14 2 0 10 11 6 11 Jan 1812 0 0" 39 2 10 16 Jun 1812 17 Jul 1813 25 10 0 17 4 3" 6 Apr 1815 30 0 0 22 10 0 May 1816 43 2 6 Feb 1817 29 3 0 21 Sep 1818 30 12 0 22 19 0 17 Jul 1820 21 5 0 15 18 9 Totals I 266 8 10 I f195 2 0 A 10 per cent discount had been allowed by Wollaston off the usual price of 15s. per ounce Platinum Metals Rev., 1987, 31, (2) 93 A section of the broad surface of the exterior brass rim of the mural circle made by Troughton for the Royal Observatory at Greenwich. The six-foot circle was mounted with its plane vertical, so Troughton’s name was closest to the stone pier on which the circle was supported; next came the auropalladium inlay, and then the platinum inlay on which was engraved the figures that indicated the degrees. Furthest from the pier was the date when the circle was completed papers (14)we know that in August 1814the Troughton’s design envisaged two metallic price for gold purchased from a London gold strips, each about 0.25 inch in width, laid in and silver merchant was 4. 8s. an ounce; so parallel channels cut about 0.25 inch apart in Wollaston sold his platinum at less than one- the broad outer surface of a brass ring which fifth the price of an equivalent volume of gold. formed the outer edge of the circle. As con- structed, one of the strips was engraved over its Troughton’s Early Use of entire length with the integral figures from I to Platinum and Palladium 360, spaced at positions corresponding to the In the year 1806 the Royal Society appointed relevant degrees of arc. The other strip was a committee to consider a recommendation engraved with transverse lines corresponding to from the fifth Astronomer Royal, Nevil degrees; and each degree was further subdivid- Maskelyne, that the Observatory at Greenwich ed into twelve equal parts by shorter lines, to should be equipped with a new mural circle indicate five-second intervals. Mounted outside (IS),to replace the mural quadrant that had the circle and separate from it were six reading been in use since 1768 but could no longer be micrometer-microscopes, spaced at equal inter- trusted. A model of a proposed instrument vals around the periphery, so that it was possi- which was designed to measure the polar ble for an astronomer carrying out observations distances of stars was shown to the committee with the mural circle to measure angles to an ac- by Troughton and in I 807 he received an order curacy of less than one second of arc (I 8). to make a circle of that type having a diameter It was essential that these strips should have not exceeding six feet (I 6). An order for the op- a bright or silvery appearance and would not tical components of the instrument was placed tarnish on exposure to the atmosphere, and for with the fm of P. & J. Dollond (17), for advice on that subject Troughton may well have Troughton suffered from colour blindness and consulted Wollaston. The latter would have on that account did not undertake optical work been aware of investigations carried out more himself, usually sub-contracting it to the fm than forty years earlier by William Lewis, who of Dollond or to another named Tulley. had found that an alloy obtained by fusing Platinum Metals Rev., 1987, 31, (2) 94 Wollaston’s note recording Troughton’s method of preparing a flat strip of auropalladium intended to form an inlay for a mural circle. The cross-section of the strip was first made semicircular,and it was then laid in a channel cut to receive it in the brass frame of the instrument. It was fixed in place by hammering, and engraving was carried out aRer the surface of the inlay had been smoothed and polished kpmduccd by pcmuwuon of the Syndics of Grnbndge UNvemity Libmry twenty carats of gold with only four of platina Troughton paid 48. 2s. @. Of that quantity proved to be pale in colour, “could scarcely be some 6.6 ounces went to form only one of the judged by the eye to contain any gold”, and strips of the Greenwich mural circle, namely “hammered well into a pretty thin plate” (19). that engraved with transverse incisions. For trial purposes Wollaston prepared sam- According to Wollaston the strip of ple specimens of a gold-platinum alloy, one auropalladium intended for use as an inlay was containing 20 per cent and the other 25 per cent first formed semicircular in cross-section, and platinum, but it seems that neither specimen was then hammered into place in the channel met Troughton’s requirements and both were cut to receive it (22). The dimensions as record- returned by him. Some years earlier Wollaston ed by Wollaston would be inappropriate for the had melted six parts of gold with one part of Greenwich mural circle, however, but might palladium and obtained an alloy which was have applied to an inlay intended for a sextant. “nearly white” in colour (4), and this may have Platinum was used for the other strip on led him to try the effect of fusing gold with which the figures I to 360 were engraved. On other proportions of palladium. A specimen the assumption that both channels cut in the containing 25 per cent palladium was found to brass rim to receive the inlays were of the same be satisfactory; as Wollaston recorded in one of depth, some 8 ounces of malleable platinum his notebooks, the alloy was “white & free as would have been required for that purpose; but need to be” (20). at the price Wollaston was then charging for In the two years from May 1808 Wollaston platinum, I 5s. an ounce, the cost of such a strip provided a total of 9.5 ounces of this 4:1 would not have been much over L6. The great specification of auropalladium (21), for which disparity in price between strips of these two Platinum Metals Rev., 1987, 31, (2) 95 Part of the brass arch of a sextant of 10-inch radius, made by Edward Troughton about the year 1819. The scale is divided into degrees and minutes from - 5 to + 140 degrees, and by using the vernier provided it is possible to take readings to 10 seconds of arc. To indicate that the scale was divided on platinum, Troughton engraved the word Platina on the adjacent brass frame Repraduced by counny of the Trustees of the Nsrionnl Museums of Scotland metals, around E25 say, may well have influenc- be found to answer the expectations formed of ed Troughton in deciding to restrict the use of its qualities”. Apparently he heard nothing (25). auropalladium to only one of the strips and to use platinum for the other. Troughton’s Sextants Troughton’s mural circle was completed in The instruments used by astronomers, 1810, and after its installation at Greenwich it navigators, hydrographers and surveyors were was in use from June I 812 until I 85 I. It is now of particular interest to Troughton, and cater- to be seen in the Pond Gallery of the Old Royal ing for their needs constituted an important Observatory at Greenwich, which forms part of part of his business. In I 788 he patented an im- the National Maritime Museum (23). proved form of sextant having a double-frame Troughton was not the only person to use construction joined together by pillars (26); it auropalladium for a mural circle. In July 1819 achieved a useful reduction in weight yet Wollaston received a letter from Franpis without any sacrifice of rigidity, a considerable Arago informing him that the French instru- advantage where sextants of large radius (8 to ment maker, Jean Nicolas Fortin, wanted a 10inches) were concerned. Such was the nature bulk of auropalladium equivalent to 19gram- of Troughton’s design that instruments of that mes of silver, for use in the mural circle that he pattern have since come to be known as pillar was making for the Paris Observatory. sextants. Wollaston calculated that 315 grammes of his None of Troughton’s sextants constructed auropalladium alloy would be required, and at before 1788 carried a manufacturer’s serial the end of the month he sent 318 grammes (just number, and this was still the case after that over 10.25 ounces) to Arago (24). At the same date in respect of his pocket sextants (radius time he provided a small piece prepared by about 3 inches). The practice of stamping a Troughton for laying into a sextant, with the serial number on the frame of every one of his comment that any length of it could be laid at pillar sextants was introduced in or soon after once into a groove cut to receive it and by ham- 1788, and the numbering started then was car- mering fmed in its place. Wollaston intimated ried on sequentially and without interruption that he would like to hear from Arago how after Simms became Troughton’s partner in work on the Paris mural circle was progressing, 1826, and was continued by the firm for many and expressed the hope that the alloy “would years after the death of Simms in 1860. Platinum Metals Rev., 1987, 31, (2) 96 A study carried out a few years ago by Stim- 1819 and now preserved in the Royal Museum son has revealed documentary evidence which of Scotland (28). serves to establish the relevant dates when Examples of 8-inch pillar sextants bearing the several Troughton sextants of known serial inscription “Platina” are to be seen in museum numbers came into, or were already in, use. collections in Britain: one made by Troughton From an analysis of that data Stimson was able around 1813 is in the National Maritime to establish that Troughton’s rate of production Museum, Greenwich (29); and another made of the pillar sextant from 1788 onwards was about 184 by Troughton & Simms is in the fairly uniform and amounted to about forty- Royal Museum of Scotland (30). three a year (27). Among the large collection of astronomical On that basis Troughton must have sold instruments assembled by a keen amateur some seven hundred pillar sextants by the time astronomer, Richard Sheepshanks (31), after he he acquired his first stock of malleable had settled in London in 1824, was a 3-inch box platinum from Wollaston, and it is probable sextant made by Troughton & Simms (32). The that a large majority of those instruments would sextant is of some interest in that the scale was have been provided with inlaid scales of silver, engraved on palladium. Nothing is known of its the remainder being of gold. date of manufacture save that it must have been Following his introduction of platinum scales later than 1825. After the death of Sheepshanks it would not have been possible to tell at a in 1855 his sister presented all his astronomical glance whether some of his sextants had a new and other scientific instruments to the Royal or recently cleaned inlay of silver, as distinct Astronomical Society (33), and the box sextant from one of platinum. To remedy this situation remained there until it was given to the Oxford Troughton had the word “Platina” or “Silver” Museum of the History of Science (34). engraved on the inner part of the brass arc In addition to the examples already quoted, it frame supporting the engraved inlay. The name is clear from notes set down by Wollaston in occupied an area equidistant from both ends of 1819 that at least two sextants made by the divided scale, as appears in the reproduc- Troughton had been provided with scales tion of a portion of the brass arch of a engraved on inlays of auropalladium (35). In Troughton 10-inch pillar sextant made about one instance Troughton was said to have The scale of a 3-inch radius box sextant made by Troughton & Simms probably in the late 1820s for Richard Sheepshanks, a keen amateur astronomer and great friend of Edward Troughton. The palladium inlay is divided to degrees and minutes, and by using the vernier shown it is possible to take readings to 10 seconds of arc Rcpmdud by courtesy of the Oxford Muwm of the History of Science Platinum Metals Rev., 1987, 31, (2) 97 Edward Troughton’s invoice for the supply to the Board of Longitude of an artificial horizon with mercury, and two 8-inch radius sextants, both described as having been divided on Platina. The in- struments were issued to Dr. J. L. Tiarks for his use when determining the longitude of Funchal in the island of Madeira Rrprcduccd by counny of the Royal Gmnwich Obxwalorv prepared a strip 9.8 inches in length and platinum that Troughton purchased from weighing 134grains, ready for laying into a sex- Wollaston over the years say from 1812through tant; the dimension quoted leads one to believe to 1820 were more than enough to enable him that the inlay was intended for a sextant of to furnish his total output of sextants over that 8-inch radius. period with platinum inlays, should customer It is also evident from another note by demand have made it desirable. Wollaston that he had been approached by Once platinum was no longer available from Dollond regarding the supply of a strip of Wollaston, it would have been necessary for auropalladium 12.2 inches in length and 0.0375 Troughton to seek further supplies from inches in thickness, suitable for laying into a abroad, perhaps from France. A note recorded sextant (36). The length specified by Dollond by Wollaston in 1820shows that Cary acquired suggests that he wanted the inlay for a sextant some platinum ingots from the firm Cuoq, of 10-inch radius. Wollaston calculated that 280 Couturier et Cie., in Paris; the price charged grains of his auropalladium would be required was equivalent to 16s. Id. an ounce, of which for that purpose, and from the dimensions sup- IS. 10d.covered freight charges (38). plied by Dollond one can deduce that in this particular instance Wollaston adopted a figure Sextant Prices of 17.2for the density of the alloy that he in- Troughton produced a printed catalogue in tended using to meet Dollond’s needs. 1782 (39) and so far as is known he issued no Wollaston did not indicate the thickness of more catalogues during the next forty-three inlay (about 0.04 inch) that Troughton used in years (40). During that period he never lacked his pillar sextants. However, Usselman has for work and may well have felt that there was found by analysing original samples of no need for him to produce a catalogue in order Wollaston’s platinum and palladium derived to advertise his wares. However, the price of a from crude platina, that a purity in excess of 99 Troughton 8-inch sextant divided on platinum per cent was attained for platinum but only 90 is known from an invoice sent to the Secretary per cent for palladium (37). So by assuming a of the Board of Longitude in July 1822 and density for platinum of say 21.2, and taking preserved with the Board’s papers. Two such Wollaston’s own determination of 17.2 for sextants were provided, only one of which was auropalladium, the weight of platinum that new and priced at E21; the second-hand instru- would be required to replace the same bulk of ment cost five guineas less (41). auropalladium in a Troughton 8-inch sextant is Both sextants were delivered to an about 167grains. astronomer, Dr. John Lewis Tiarks (42), who On that basis one can say that the stocks of was sent by the Board on a mission to ascertain Plarinum Merals Rev., 1987, 31, (2) 98 “with the greatest possible accuracy the the option of acquiring a sextant divided on longitude of Funchal” on the island of Madeira palladium was not present in the catalogue (43). This action was made necessary after the reproduced in 1829, nor in any of the sixth Astronomer Royal, John Pond, stated his catalogues printed from 1844 onwards; but it belief that the longitude of the island, as then does appear in all the firm’s catalogues publish- known to mariners, was in error (44). A new ed from 1832 to 1838 inclusive. value for the longitude of Funchal was subse- As no catalogue listed auropalladium scales as quently reported by Tiarks and was published an option, one may wonder whether the box by the Royal Society (45). sextant mentioned above as having been made It may have been the influence of Simms after for Sheepshanks is a unique example. he became Troughton’s partner that brought about a change of outlook by the firm regarding Some Followers of Troughton the need for a printed catalogue. In 1829 the Several well-known makers of sextants ap- editor of the Astronomischen Nuchrichten must pear to have followed Troughton’s practice of have had access to a copy of a Troughton 81 using the word platina to indicate that a scale Simms catalogue, for he printed the details in a was divided on platinum metal. The earliest ex- supplement to the December issue of that jour- ample seen so far is in an advertisement present nal (46). It would seem that the catalogue in its at the end of a work written for use by pupils original form would have been five pages in at Oundle School under the patronage of the length. Grocers’ Company of London (50). It carries Only one other separate catalogue is known “A list of such Instruments, as are requisite for to have been produced by the firm before the the Young Surveyor, or Student in 1880s. It is an eight-page undated document, Mathematics, made at the lowest Prices, by R. and is preserved with the papers of George Bid- Banks, 441, Strand, London”. The final entry dell Airy, the seventh Astronomer Royal (47). on that list reads: Some guide as to its approximate date can be “A 3-inch Pocket Sextant, with recent im- derived from the document itself and indicates provements, the divisions on brass, silver, that the catalogue could not have been printed platina, or gold, to one minute, a most accurate, before September 1838, and probably no later portable, and useful Instrument”. than 1841. The price-range was from three to four guineas. The prices given in that catalogue and No extant example of such a Banks sextant relating to the firm’s 8-inch improved sextants divided on platinum has yet been located. with double frames are as follows: Aberdeen University has an invoice dated Divided on Silver to 10 seconds...... t18 18s. 2nd May 1812 for the supply to Marishall Col- Divided on Platina or Palladium...... t21 0s. lege in Scotland by William Cary, of 182, near Divided on Gold...... t23 2s. Norfolk Street, Strand, London, of a 10-inch These same prices are present in all copies of reflecting circle costing L18. 18s. (51). A Col- the firm’s catalogues that are present as end- lege inventory drawn up in 1823 describes the papers to a book written by Frederick Walter circle as having a “platina arch” (52). Simms, the first edition of which appeared in In the collection of instruments preserved at 1834 (48), and in at least six of the seven later the Italian Istituto Geografico Militare, in editions of the work that appeared over the next Florence (53), there is a sextant with the word thirty-one years. No copy of the 5th edition has “Platina” engraved close to and on one side of been located. Finally, there is another catalogue the divided scale; on the other side the maker’s at the end of a book published in 1852 by name is engraved “J. D. Potter, Poultry”. William Simms (49). From London trade directories we know that A comparison of all the relevant catalogue en- John Dennett Potter was the successor of tries dealing with the firm’s sextants shows that another notable instrument maker at that Platinum Metals Rev., 1987, 31, (2) 99 address, namely Robert Brettell Bate who died Acknowledgements in 1847. I am grateful to the following for their assistance in as a final example, one may cite an 8-inch the preparation of this article: John Burnett and Alison Morrison-Low, Royal Museum of Scotland; brass pillar sextant engraved “Lilley i% Son, David Coffen, HastinB-on-HudWn, New York; London” which has an inset platinum arc, and Janet Dudley, Royal- Greenwich Observatory, is labelled “Platina” (54). London trade direc- Herstmonceux; Dr. John Reid, apartment of Physics, Aberdeen University; Carole Stott, National tories indicate that John Lilley did not take his Maritime museum,Greenwich; greenwich; and D~.andGerard dr. Gerard son into partnership until around 1845. Turner, Museum of the History of Science, Oxford. References I M. L. [J.-B. Leblond], Obsns Physique (Rozier), 27 A. N. Stimson, Vistas in Astronomy, 1976, 20, 1785,27, 362-373 123- I30 2 T. 0. Bergman, Kungl. Vetensk. Akad. Handl., 28 Inventory no. 1986.L3.1 1777,389 317-328 29 Inventory no. S.152 3 B. I. Kronberg, L. L. Coatsworth and M. C. 3o Inventory no. 1986.~3.2 Usselman, Ambix, 1981,28, 20-35 31 Obituary notice: Mon. Nores Roy. Astr. Soc., 4 w. H. Wollaston, Phil. Trans., 1804, 94, 1856, 16, 90-97; reprinted in Mem. Roy. Astr. 419-430 Soc., 1857,25, 154-162 5 s. Tennant,0Phi, Trans.’ 18049 94, 411-418 32 Anon, Mon. NoresRoy. Astr. Soc., 1876,36, 130, 6 W. H. Wollaston, Phil. Trans.,. 1829, ~. 1x9,.. 1-8 57 item no. 2, 7 J. A. Chaldecott, Platinum Metals Rev., 1979,23, 33 Ibid., 1857, 17, 223; 1858,18, 88-89 112-123 34 Inventory no. 31.6.57 8 Cambridge University Library Add. MSS 7736, 35 Op.cit.,(Ref. 20), 15:entries Januaryand June 1819 notebook I, 4 36 Ibid., 19 9 Obituary notices: Ma. Notes Roy. Astr. SOC., 1836, 3, 149-155;reprinted in Mem. Roy. Astr. 37 Op. cit., (Ref. 3), 24 SOC.,1836, 9, 283-290; Dictionary of National 38 Op. cit., (Ref. 8), notebook K Biography, London, 1899, 57, 259-260 39 Bodleian Library, Oxford: the John Johnson I0 E. Troughton, Proc. Roy. SOC., 1809, 99, Collection 105-145 40 J. Burnett, private communication, Feb. 1986 I1 Vickers hardness figure for both platinum and 41 Royal Greenwich Observatory archives, RGO palladium is 40, and for silver 26 14/48,sect. 36, folio 37or I2 Op.cit., (Ref. 8), notebook L, entry 8 March 1806 42 Obituary notice: Mon. Nores Roy. Astr. SOC., I3 Summarised from entries in op. cit., (Ref. 8), 1838,4, 108-110;reprinted in Mem. Roy. Astr. notebooks I, K and L SOC.,1838, 10, 394-397 14 Op. cit., (Ref. 8), loose sheet in notebook of Ten- 43 Royal Greenwich Observatory archives, RGO nant’s income and expenditure account 14/49,sect. 7, folios 161r-v 15 Figured in J. Pond, “Astronomical Observations 44 Ibid., folio I6or made at the Royal Observatory at Greenwich”, 45 J. L. Tiarks, Phil. Trans., 1824, 114, 360-371 London, I, frontispiece; pl. 1815, 1833,9, 1-2 46 Anon, Astr. Nach., 1829,8, (I~o),cols. 37-42 16 Royal Greenwich Observatory archives, RGO Royal Greenwich Observatory archives, RGO 6/22, folios 55r-v 47 61160, sect. 10, folios 147r-150~ [H.] D. Howse, “Greenwich Observatory”, Lon- 17 48 F. W. Simms, “A Treatise on the Principal don, 1975,3,26-30 [one of three volumes by dif- Mathematical Instruments employed in Survey- ferent authors] ing, Levelling and Astronomy”, London, 1st 18 W. Pearson, “An Introduction to Practical Edn., 1834, endpapers Astronomy”, London, 1829,2, 478 49 W. Simms, “The Achromatic Telescope”, Lon- 19 W. Lewis, “Commercium Philosophico- don, 1852,separate pagination 1-15 Technicum”, London, 1763, 526 50 T. Dix, “A Treatise on Land-surveying”, Lon- cit., (Ref. 8), notebook “Forsteraccount”, 20 Op. 12 don, 3rd Edn., 1808, 176-180,pl. 11, figs 1-2; 21 Ibid., 13 and endpaper 22 Ibid., 16 51 Aberdeen University Library MS M.361/1/68/1 23 Inventory no. M.5 52 Ibid., Knight MS M.119 24 Op. cit., (Ref. 20), 17 53 Address: Via C. Battisti 10, Firenze, Italy 25 For the text of Wollaston’s letter to Arago, see op. 54 D. Coffeen, “Tesseract Catalogue B: Early Scien- cit., (Ref. 3), 26-27 tific Instruments”, Hastings-on-Hudson, New 26 E. Troughton, British Parenr 1644 of 1788 York, 1982,item 34 Platinum Metals Rev., 1987, 31, (2) 100 ABSTRACTS of current literature on the platinum metals and their alloys PROPERTIES Oxygen Generated Platinum, Rhodium and Palladium Volatile Losses from Pure Magnetic Phase Diagram of Ordered Metals and Their Alloys (Fe -.MnJPt Alloys M. RUBEL, M. PSZONICKA, M. F. EBEL, A. JABLONSKI A. Z. MENSHIKOV, V. P. ANTROPOV, G. P. GASNIKOVA, and v. PALCZEWSKA,~.Less-Common Met., 1986,125, YU. A. DOROFEYEV and V. A. KAZANTSEV, 3. Magn. & 7-24 Magn. Muter., 1987, 65, (I), 159-166 Various techniques have been used to determine The magnetic structure and magnetic phase transi- volatile products generated from Pt, Pd, Rh, Pt-Rh tions of ordered (Fe,,hlnJPt alloys were in- and Pt-Pd-Rh. The materials were oxidised with 0, vestigated by neutron diffraction in the temperature or r.f. 0 plasma. Rho,, a-PtO,, PdO and probably range 4.2-9mK. A complete magnetic phase PtO, were produced using the 0 plasma, while diagram is presented, where the regions for different Rho,, a-PtO, , PdO and PtO were generated during magnetic states and the character of transitions bet- 0, interaction. Oxides generated by plasma from Pt- ween them are shown. Pd-Rh were enriched with Pd, and P.h to a lesser ex- tent. No enrichment was detected for oxides formed Pt-Si Contact Metallurgy Formed by by plasma etching Pt-Rh.Oxides obtained in 0,were Three-Temperature Annealing Sequen- distinctly enriched with Pt, and oxide formation ces and Short Annealing Time decreased with increased Rh or Pd in the alloys. C.-A. CHANG and R. SEGMULLER, 3. Appl. Phys., 1987, Preparation of Amorphous Palladium- 61, (I), 201-205 Rase Surface Alloys on Conventional R-Si contact metallurgy has been studied via a wide Metals by Laser Treatment range of annealing sequences using a three- N. KUMAGAI, K. ASAMI and K. HASHIMOTO, 3. Non- temperature annealing process but with shorter an- Cyst. Solids, 1986, 87, (1-2), 123-136 nealing durations than usual. With 2oo-300-500°C or 2oo-300-450°C processes, and a total annealing An attempt was made to prepare an electrocatalytical- time of 20-40 min in a N,:H, mixture of ratio 9:1, ly active amorphous Pd alloy covering a conventional crystalline bulk metal, which would act as elec- all the PtSi fdms formed showed a complete reaction an between and Si, which is a necessary condition. trical conductor for use in electrodes. Laser surface R melting and subsequent self-quenching vitrified the Hydrogen Induced Changes in the entire surface of a Pd-25Rh-1oP-gSicast alloy when Metallurgical Interactions at PtSi-Si it was transversed by a continuous CO, laser. The surface alloy needs to be bonded to the substrate, Interfaces prior to laser treatment, to ensure rapid heat absorp- T. T. BARDIN, J. G. PRONKO, R. C. BUDHANI and R. F. tion from surface to substrate. BUNSHAH, 3. Vac. sci. Technol. A, 1986, 4, (6), 3 121-3126 Effects of Short-Range Order on the The role of H in the kinetics of interfacial reactions Electrical Resistivity of Plastically between Pt,Si,, (x=0.67, 0.5) thin films and Si Deformed Pd-Ag and Pd-Ag-Fe Alloys substrates, and consequent changes in the electrical A. RAOUFI, s. ARAJS and K. v. RAO, Phys. Status Solidi, characteristics of PtSi/Si Schottky diodes were 1986, 97, (21, 571-577 studied. The absolute H concentration in the fdms The effects of plastic deformation on the electrical decreases with increasing temperature of deposition resistivity of Pd loo -,Ag, (x = 25, 30, 40, 45 and so), and increasing Pt concentration. For films with x Platinum Metals Rev., 1987, 31, (2), 101-107 101 CHEMICAL COMPOUNDS Synthesis of a New Family of Water- Iodo-Bridged Complexes of Platinum(I1) Soluble Clusters: Ru3(CO) ,*-%LX and Synthesis of cis Mixed-Amine (x= 1 -3), Os,(CO),,L,, and Ir,(CO),L, Platinum(I1) Compounds (L=Trisodium Salt (Hydrated) of Tris(m- su1fonatophenyl)phosphine) F. D. ROCHON and P. C. KONG, Can. 7. Chem., 1986, 649 (9), 1894-1896 B. FONTAL, J. ORLEWSKI, C. C. SANTINI and J. M. BASSET, InOw. Chem., 1986, 25, (24), 4320-4322 Iodo-bridged Pt(I1) dimers [Pt(L)I,] with ligands L containing N as the donor atom have been synthesis- The synthesis of a new family of water-soluble metal ed from the reactions of cis-[Pt(L),I,] with per- clusters, based on the hydrosoluble ligand chloric acid. The dimers can be cleaved in aqueous L = P[C, H, -m-SO;Na+(H, O)], is discussed. The media by a second N ligand to produce isometrically title Ru , cluster has been obtained by three routes. pure cis-[Pt(L)(L')I,]. These compounds can be converted to the chloro or carboxylato compounds by precipitating the iodo ligands with a Ag salt and ad- ELECTROCHEMISTRY ding KCI or a carboxylate salt. Oxygen Evolution at Platinum Electrodes Synthesis and Electrical Conductivity of a in Alkaline Solutions 1. Dependence on New Family of Pt Mixed Valence Com- Solution pH and Oxide Film Thickness plexes: Pt6(IVH3),,ClIOX4 (X=C104, BF, v. I. BINS and A. DAMJANOVIC, J. Electrochem. soc., and PF6) 19879 134, (11, 113-117 M. TANAKA and I. TSUJIKAWA, Bull. Chem. soc. Jpn, The 0, evolution reaction at Pt electrodes in alkaline 1987, 59, (9), 2773-2778 solution at various pHs is re-examined. Two linear V- A new family of Pt mixed valance complexes was syn- log i regions exist, each having a different dependence thesised from Magnus' Green Salt [Pt(NH,),I[PtCI,I on Pt oxide film thickness and OH- concentration. by partial oxidation using an oxidant of H ,0 or elec- The rate of 0, evolution is strongly dependent on trochemically. After partial oxidation 1/6 of CI- fdm thickness at high current densities, but indepen- ligands from Magnus' Green Salt are randomly dent at low current densities. replaced by NH, ligands and simultaneously counter ions X are introduced. These complexes comprise High-Temperature Steam Electrolysis one-dimensional chains with direct Pt atom contact. Using SrCeO ,-Based Proton Conductive The electrical conductivity u was measured from 80K Solid Electrolyte to mom temperature. The u at room temperature is H. IWAHARA, H. UCHIDA and I. YAMASAKI, ht. J. high which suggests that u along a chain direction Hydrogen Energy, 1987, 12, (2), 73-77 may beas highas that of K,[Pt(CN),]Br,,,.xH,O if High-temperature steam electrolysis was studied us- single crystals could be obtained. ing solid proton conductors based on SrCeO, at Annual Survey of Ruthenium and 700-90o0C, and using Pt or Ni as the cathode. The Osmium for the Year 1984 current efficiency for H, evolution was >95% at a current density of o.2A/cm2 at 8o0°C, but it decreas- P. A. SHAPLEY, Organomet. Chem., 1987, 318, 3. ed with increasing temperature. (1-3), 409-468 Ru and 0s organometallic complexes are presented Electrochemical Preparation of a Pt-Ru for the year 1984. Mononuclear, dinuclear and Alloy polynuclear complexes are examined, as are Ru,, M. A. QUIROZ, I. GONZALEZ, Y. MEAS, E. LAMY-PITARA Os,, Ru,, Oss,Ru,, Os, and higher nuclearity and J. BARBIER, Electrochim. Acra, 1987, 32, (2), clusters. Typical reactions of the complexes are 289-291 discussed and theses and other reviews are mention- ed. (387 Refs.) The electrochemical reduction of Pt(1V) and Ru(II1) in separated and mixed solutions on a Pt electrode in A General Route for the Synthesis of IN HCI solution showed that simultaneous reduction Tetranuclear Clusters Containing Closed of both occurred and led to alloy formation. Triruthenium and Triosmium Triangles Palladium/Hydrogen Membrane Elec- G. A. FOULDS, B. F. G. JOHNSON, J. LEWIS and R. M. SORRELL, J. Chem. Soc., Dalton Trans., 1986, (12), trode for High TemperaturelHigh 2515-2518 Pressure Aqueous Solutions Cluster compounds [N(PPh,),l[M,M'(CO),,] z. NAGY and R. M. YONCO, J. Electrochem. soc., 1986, (where M=Ru or Os, and MI=&) and 133, (1 I), 2232-2235 [N(PPh,),][M,M'H(CO),,] (M=Ru or Os, M'=Fe, A Pd-Ag alloy membrane with suitable H, partial Ru or 0s) have been prepared in good yield by the pressure on the dryside has been utilised as an elec- reaction of an appropriate tetracarbonylmetallate trode for high temperaturehigh pressure aqueous with bis(acet0nitrile) complexes. The anionic clusters solutions where fast relaxation measurements of the have been protonated to give the corresponding electrode kinetics are made. The Pd-Ag membrane neutral hydride clusters. acted as a classical H electrode between 100-300~C. Platinum Metals Rev., 1987, 31, (2) 102 New Types of Anodes for the Oxygen Photoassisted Hydrogen Production from Evolution Reaction in Acidic Solution a Methanol-Water Mixture on Platinized IrO /Ti0 /Ti Cr 0 -Doped Ti0 Y. MATSUMOTO, T. TAZAWA, N. MUROI and E.-I. SATO, A. SOBCZYNSKI, 3. Mol. catal., 1987, 39, (I), 43-53 3. Electrochem. SOC.,1986, 133, (11), 2257-2262 Reduction of previously adsorbed Pt'+ species on IrO,/TiO,/Ti electrodes, where porous TiO, films TiO, was used to obtain highly active catalysts for H, are made by anodic oxidation accompanied by spark- photoevolution from a CH,OH-H,O solution. A ing, were tested as the anode for the 0, evolution quantum yield up to 22% was observed. Optimum Pt reaction in acidic solution. Thermal decomposition of coverage and most favourable reaction conditions aqueous Ira, solution provided the IrO,. The were found. Although the OZOldopant shifts the catalytic activities of these electrodes are higher than anatase spectrum into the visible, it is not possible to those of an IrO,/Ti electrode, and electrodes obtain H, with light of energy smaller than the prepared at 550°C are superior in long-term tests. bandgap of TiO, . An Iridium-Based Mercury-Film Elec- Study of Photocatalytic Reaction of trode. Part 1. Selection of Substrate and Methanol with Water over Rh-, and Pd- Preparation Loaded TiOz Catalysts. The Role of Add- S. P. KOUNAVES and J. BUFFLE, 3. Electroanal. Chem. ed Alkali Metal Cations Interfacial Electrochem., 1987, 2x6, (I and 2), 53-69 S. NAITO, Can. 3. Chem., 1986, 64, (9), 1795-1799 A Hg-film electrode with Ir as substrate was The product selectivity of the photocatalytic reaction developed. Of several metals tested only Ir had the of methanol with water is changed drastically by the desired properties for bearing Hg. It is recommended addition of alkali metal cations (Na) to Rh- and Pd- that pretreatment should include polishing with I pm loaded TiO, catalysts. Over catalysts without alkali diamond, rinsing with chromic acid and cathodising metal cations the main products are a I:I ratio of H, at -2.oV vs. S.C.E. and dimethoxymethane, which changes to H,, Oxidation of 4,41-Dichlorobiphenylat a methyl formate and CO, when alkali metal cations Ruthenium Dioxide Anode are added. The added cations stabilise the reaction in- termediate as adsorbed formate instead of adsorbed S. LAULE, R. HAWK and D. MILLER, 3. Electroanal. formaldehyde, thus causing the product selectivity to Chem. Interfacial Electrochem., 1986, 213, (4, change from dimethoxymethane to methyl formate. 329-332 The destruction of difficult-to-destroy Light-Induced Reduction of Rhodium polychlorinated biphenyls (PCBs) was investigated (111) and Palladium (II) on Titanium Di- using a RuO, anode. The destruction could be ac- oxide Dispersions and the Selective complished via electrochemical oxidation at a RuO, Photochemical Separation and Recovery anode, using a Pt cathode and a Ag/Aga reference of Gold (III), Platinum 0,and Rhodium electrode. (III) in Chloride Media Selective Formation of HCOO- in the E. BORGARELLO, N. SERPONE, C. EMO, R. HARRIS, E. Electrochemical CO Reduction Catalys- PELIZZETTI and C. MINERO, hrg. Chem., 1986, 25, ed by [R~(bpy)~(CO),l~+ (bpy=2,2'- (251, 499-4503 bipyridine) Irradiation of aqueous TiO, dispersions containing H. ISHIDA, n. TANAKA, K. TANAKA and T. TANAKA, 3. Pd(I1) or Rh(II1) chloride salts with AM1 simulated Chem. Soc., Chem. Commun., 1987, (2), 131-132 sunlight caused photoreduction of the metals. Oz The electrochemical reduction of CO, catalysed by deterred Rh(II1) photoreduction, but not Pd(I1) photoreduction. Reduction is most efficient in the [R~(bpy),(C0),]~+ in MeOH or MeCN in the presence of several proton sources selectively forms presence of CH ,OH. The selective photoreduction HCOO- at a fast reaction rate. On increasing the and recovery of a mixture of Pt(IV), Rh(II1) chloride and Au(II1) were tested against parameters for pH, pK, value of the proton source the selectivity for HCOO- formation increases. 0, presence, presence of a hole scavenger and semiconductor concentration. PHOTOCONVERSION Photoreduction of C02 to CH, in Aqueous Solutions Using Visible Light Photocatalytic Decomposition of Formic R. MAIDAN and J. WILLNER, 3. Am. Chem. soc., 1986, Acid on Platinized n-Type Silicon Powder 108, (IS), 8100-8101 in Aqueous Solution CO, can be photocatalytically reduced to CH, using H. YONEYAMA, N. MATSUMOTO and H. TAMURA, Bull. tris(bipyrazine)Ru(II) as sensitiser, and a Ru metal Chem. SOC.Jpn., 1986, (IO), 3302-3304 colloid as catalyst. The system consists of an aqueous Photocatalytic decomposition of aqueous formic acid solution of pH 9.5 which includes NaHCO,, was successfully achieved using platinised n-type Si Ru(bpy) + , TEOA as electron donor, and a Ru col- powder as a photocatalyst, which was spread on the loid. When illuminated at >420nm under a gaseous bottom of a reaction cell. CO, atmosphere, CH, formed. Platinum Metals Rev., 1987, 31, (2) 103 ELECTRODEPOSITION AND Electrocoated Layer Compound Materials SURFACE COATINGS Based on Palladium for Plug Connectors D. RUHLICKE, G. BAR, HAGENI and H. HEYNE, Neue Structure and 7OOOC Hot Corrosion M. Huette, 1987, 32, (2), 77-80 Behavior of Chromium Modified Results of work on contact materials for highly Platinum-Aluminide Coatings reliable plug connectors are presented. It was found M. DUST, P. DEB, D. H. BOONE and S. SHANKAR, J. vac. that electroplated layers, combinations of the type Sci. Technol. A, 1986, 4, (6), 2571-2576 2pmPd/o.2pmAu and ~mNihpmPd/o.~pmAuwere The 7moC hot corrosion testing of Cr modified Pt most suitable. The plating conditions are discussed. aluminides was studied to determine whether com- bined additions of G and Pt were even more beneficial. The substrates used were two commercial LABORATORY APPARATUS Ni-base superalloys. The structure of the G modified AND TECHNIQUE Pt aluminide coating was dependent on the sequence of modifying element addition. The optimum coating Electrochemical Detection for Liquid for this resistance was obtained by the Cr-Pt-Al Chromatography Using the Wall-Jet deposition sequence which gave a coating with a con- Cell/Ultramicroelectrode Detector tinuous PtAl, layer on the surface backed up with a S. B. KHOO, H. GUNASINCHAM, K. P. ANG and B. T. TAY, fairly high level of Cr and Pt. J. Electroanal. Chem. Interfacial Electrochem., 1987, Pulsed Current Electrodeposition of 216, (I and 2), 115-126 Palladium A carbon fibre array and a Pt thin ring ultramicroelectrode were constructed and used with a S. YOSHIMURA, E. CHIDA and E. SATO, Met. Finish., large volume wall-jet cell for amperometric detectors 1986, 84, (101, 39-42 in liquid chromatography. Electrode characterisation Ethylenediamine-Pd(I1) complex solutions as the was performed. This combination has much reduced electrolyte, Pt-coated Ti as anode and 0-free Cu sheet flow rate dependence compared to the wall-jet as sample electrode were used in an electrolytic cell of cellkonventional electrode system. Liquid volume 25ocm’ to examine Pd electrodeposition us- chromatography in the absence of supporting elec- ing DC and pulsed current. The effects of electrolytic trolyte was possible and had good sensitivity using parameters on electrodeposition morphology, occlud- the ultramicroelectrode. ed H content and current efficiency were also measured. Pulsed current electrolysisproduced a fine Chemically Responsive Microelectro- grained smooth electrodeposit with decreased H con- chemical Devices Based on Platinized tent. Important factors affecting electrodeposit mor- Poly(3-Methylthiophene): Variation in phology were the overpotential and the effect of mass Conductivity with Variation in Hydrogen, transfer. The overpotential for reasonable current ef- Oyxgen, or pH in Aqueous Solution ficiency, H content and electrodeposit morphology was 200-4oomV. J. w. THACKERAY and M. s. WRIGHTON, 3. Phys. - Chem., 1986, 90, (IS), 6674-6679 Investigation of Laser-Assisted Palladium Microelectrochemicaltransistors were prepared from Deposition Au microelectrodes and platinised qo!y- F. FRIEDRICH and CH. 1. RAUB, Galvanotechnik, 1986, (3-methylthiophene) (P). The change in conductivity 77, (II), 2658-2664 of (P) with change in redox potential is the basis for The effect of laser light was examined for Pd deposi- amplification of electrical or chemical signals; con- tion from ammoniacal Pd electrolytes. Other effects ductivity varying 5-6 orders of magnitude upon on the structure of the deposited layers which were change in potential from +0.2 to +0.7V vs. S.C.E. examined included thickness and thermal conductivi- in aqueous electrolyte. The F’t equilibrates (P) with ty of the substrate, pH of the electrolyte and changes the O,/H,O or H,O/H, redox couples. The tran- in cathodic polarisation voltage. The deposition of sistors can be used as room temperature sensors for Pd-Ag alloy layers was favourably affected by laser 0, and H, in aqueous solutions. radiation. Blackbody Having a Platinum Heater and Palladium Plating Technique Temperature-Sensitive Element Res. Discl., 1986, (270), 618 G. K. KHOLOPOV, S. G. GALIEVA, A. S. CHERYUKANOV, Ni-plated piezoelectricceramic tubes, used for ink jet N. YU. BEREZKINA, YU. L. VOLKOV, A. G. MATVEEV and printing can be given an overplate of Pd which P. A. POTEIKO, Sov. J. Opt. Technol., 1986, 53, (3), significantly improves resistance to corrosion. Pd 143- I45 plating is added to the Ni coating on the tubes by The construction and operation of a small blackbody replacing the Ni/film with a Pd seed layer by a is described which is to be used as a thermal radiation galvanic reaction, and electrolessly depositing a Pd source and designed for temperatures from film over the seed layer. This process produces non- 50-25oOC. The temperatures are determined by porous films with good adhesion. The tubes can be measuring the resistance of a Pt wire which also plated first with Ni when they have no coating. serves simultaneously as the heater winding. Platinum Metah Rev., 1987, 31, (2) 104 An Electrochemical Oxygen Separator A Study of Supported Platinum Catalysts Using an Ion-Exchange Membrane as the for the Production of Hydrogen Cyanide Electrolyte by the Ammoxidation of Methane Y. FUJITA, H. NAKAMURA and T. MUTO, 3. Appl. Elec- G. 1. HUTCHINGS, Appl. &id., 1986, 28, (1-2), 7-11 trochem., 1986, 16, (6), 935-940 The ammoxidation of CH, to produce HCN has been An electrochemical 0, separator with two electrodes investigated over Pthryl (Be,AI,Si,O,,). The and an ion-exchange membrane has been developed. method of preparing the catalysts significantly af- The anode consists of a Nafion membrane plated at fected the yields of HCN. Supported catalysts are less g.7mg/cm2with Pt; the cathode, bonded to the other affected by space velocity and poisons, such as Fe, side of the membrane, was formed from a slurry of than gauze catalysts for this reaction. graphitised furnace black loaded with Pt at Influence of Sulfiding Method on Proper- o.2mg/cm2. Nafion solution and a PTFE dispersion ties of Platinized and Platinized-Iridized were added to the slurry. The separator could be operated at 2oomA/cmz and produced 70.gcm3/min Alumina Reforming Catalysts 0, of 98.4% purity. V. L. MEDZHINSKII, B. B. ZHARKOV, L. F. BUTOCHNIKOVA and A. N. KRASIL’NIKOV, Chem. Hydride Formation as a Measure of Alloy- Technol. Fuels Oils, 1986, 22, (3/4), 165-168 ing in Bimetallic Systems Containing The effect of methods used to introduce bound S on Palladium the activity and stability of monometallic and S. B. ZIEMECKI, J. B. MICHEL and G. A. JONES, React. bimetallic reforming catalysts has been studied. After Solids, 1986, 2, (3), 187-202 preparation the catalysts were reduced at 5o0°C and The measurement of the H:Pd ratio as an indication sulphided at 340°C with a H,:H,S=IO:I mixture of alloying has been studied during temperature pro- and then purged of H, S. Catalyst activity in heptane grammed reduction (TPR). Pd-Re and Pd-Au alloys reforming was then investigated at 475OC and IMPa were formed during TPR from the component pressure. Sulphiding the catalysts after reduction is metals. The extent of alloying is related to the sup- more effective: the selectivity in cracking reactions is pression of P-PdH formation. lowered by a factor of >2 and the selectivity in aromatisation is increased by a factor >3. Adding Behavior of Hydrogen in Palladium- o.xwt.%Ir to o.36%Pt/Al20, doubles the cracking Aluminium Metal-Oxide-Semiconductor selectivity. Structures Monodisperse Colloidal Metal Particles F. ENQUIST, M. ARMGARTH and I. LUNDSTR~M, 3. from Nonaqueous Solutions: Catalytic APP~.Phrs., 1986, 60, (12), 4297-4299 Behavior in Hydrogenation of But-1-ene A new way of studying H in composite metal films by of Platinum, Palladium and Rhodium using H sensitive Pd gate MOS devices is described. Particles Supported on Pumice MOS structures with composite films of Pd and Al M. BOUTONNET, J. KIZLING, V. MINTSA-EYA, A. were made and the behaviour of H atoms in the CHOPLIN, R. TOUROUDE, G. MAIRE and P. STENIUS, 3. passive Al and at the metal-metal interface was ex- Cad., 1987, 103, (I), 95-104 amined. Although H atoms pass through the non- Monodispersed particles of Pt(2-3nm), Rh(2-3nm) catalytic Al layer, there are no adsorption sites with or Pd(5nm) were dispersed via reverse micellar solu- polarised H atoms at the Al-SiO, interface. tions on pumice to form catalysts. Catalysts formed using aqueous or alcoholic solutions produced large aggregates. Catalytic reactions for deuteration, HETEROGENEOUS CATALYSIS isomerisation and H,-D, exchange of but-I-ene were n-Octane Dehydrocyclisation on Mono- performed and properties compared. The activities functional and Bifunctional Pt/AI, O3 per metal surface area were similar. Pt prepared from microemulsionsshowed unusually high selectivity for Catalyst isomerisation. c. T. AKO and A. A. susu, 3. Chem. Technol. Biotechnol., 1986, 36, (XI),519-526 Synthesis of Acetylene-Terminated The dehydrocyclisation of n-octane to iso-octane, Monomers Using a Polymer-Supported ethylbenzene and 0-, m- and p-xylene was in- Palladium Catalyst vestigated on monofunctional (non-acidic) and D. L. TRUMBO and c. s. MARVEL, 3. Polymer Sci., bifunctional (acidic) Pt/Al,O, catalyst in a Polymer Symposium 74, 1986, 45-53 microreactor with H, at 563-673K. On bifunctional A single crystal polyethylene bound Pd catalyst was Pt/Al ,0, the total conversion of n-octane decreased prepared and used instead of a free Pd catalyst for the from a high value with increasing temperature; the synthesis of acetylene-terminated monomers. The primary product being iso-octane. On monofunc- yields were lower, 57-64% versus 83-86% for the tional Pt/Al, 0, the total n-octane conversion increas- free Pd catalyst, but the advantages of the bound ed initially and went through a maximum as the catalyst outweigh the loss of yield; these include temperature increased; the primary products were recyclability which lowers costs in the long run, and ethylbenzene and o-xylene. the products are not contaminated with Pd. Platinum Metals Rev., 1987, 31, (2) 105 Exhaust-Catalyst Development for Ammonia Synthesis over Alumina and Methanol-Fueled Vehicles. 2.Synergism Magnesia Supported Ruthenium: Com- between Palladium and Silver in parative Kinetic Study of the Promotive Methanol and Carbon Monoxide Oxida- Action of Metallic and Ionic Potassium tion over an Alumina-Supported H. BARIS, M. GLINSKI, J. KIJENSKI, A. WOKAUN and A. Palladium-Silver Catalyst BAIKER, Appl. catal., 1986, 28, (1-2), 295-301 R. W. McCABE and P. 1. MITCHELL, 3. CUtd., 1987, The effect if K and KNO, promoters on NH, syn- 103, (21, 419-425 thesis over Al,O, and MgO supported Ru was in- CH,OH and CO oxidations were examined over vestigated in a fmed-bed reactor at 300-725K at o.oIPd, 5% Ag and o.o~%Pd-s%Agcatalysts sup- 150kPa. Promotion with K increased the turnover ported on p41z03,The bimetallic catalyst showed frequency of the Ru/Al,O, 90 times and -60 times greater oxidation activity than the single component for Ru/MgO at 623K. The KNO, had little effect. catalysts, and the Pd and Ag acted synergistically in the bimetallic catalyst to produce greater CO and HOMOGENEOUS CATALYSIS CH,OH oxidation rates and lower yields of methanol partial oxidation products than expected. Phase-Transfer and Metal-Complex Catalysis with Quaternary Ammonium Selective Decomposition of Isobutyl- Chlorometallates aldehyde to Propene, Carbon Monoxide I. G. IOVEL, Y .SH. COLDBERG, M. v. SHYMANSKAand E. and Hydrogen LUKEVICS, 3. Chem. soc., Chem. Commun., 1987, (I), K. FUJIMOTOand T. KUNUGI, Appl. catal., 1987, 29, 31-32 (2), 203-210 Quaternary ammonium chlorometallates prepared Supported Pd modified with Na,S was an excellent with complexes of PtI", 19" and FeIII were produced catalyst for the selective decomposition of iso- and their bifunctional catalytic properties were tested bulylaldehyde to propene, H, and CO. The conver- in the hydrosilylation reaction of phenylacetylene sion was -9%and 99% propene was produced with triethyl- and (dimethy1)phenyl-silane (metal- selectively at 35OC under atmospheric pressure. The complex catalysis), followed by addition of S ion suppressed the secondary reaction of propene dichlorkarbene (phase-transfer catalysis). Their and H, and promoted the desorption of CO. catalytic activity for both reactions studied was not Lanthanum Oxide Promoted lower than that of conventional catalysts, thus two Rhodium/Titania and Rhodium- reactions can run consecutively in the same vessel. PIatinumRitania Catalysts for Alcohol Coordination Chemistry with Alkanes: Formation from Synthesis Gas Homogeneous Solutions for Reactive sp G. c. BOND and D. G. RICHARDS, Appl. Catal., 1986, C-H Bonds 2% (1-2), 303-319 M. L. DEEM, Coord. Chem. Rev., 1986, 74, 101-125 Ti0,-supported Rh and Rh-Pt catalysts have been Cleavage of alkane C-H bonds, by metals from studied for the selective formation of oxygenates from Groups 3d, 8d, @ and ~od,including Pt(II), Pd(II), synthesis gas. Adding La,O, as a promoter Ir(O), Ir(I), Ir(III), Rh(I), Os(II), Ru(0) and Re, is significantly increased the C, H, OH selectivities and considered for non-aqueous liquid systems at formation rates. Pt addition increased overall activity <15ooC. Alkane conversion to H2 and alkenes is of and with La,O, gave higher alcohol selectivities of industrial importance and this method is a different 25%, compared to 6% for unpromoted Rh. The way to the same products as catalytic reforming of La,O, seems to promote the formation of the hydrocarbons. Driving forces for the homogeneous C, H, OH, while Pt increases hydrogenation. phase C-H sp' bond activation are identified, and in Modification of Product Distribution a typical reaction several of the driving forces par- through Periodic Operations; Fischer ticipate to allow regioselective conversion (at low Tropsch Synthesis over Ru/Al 0 levels) of n-octane to 2-octene by chlorotris- (triphenylphosphine)Rh(I) if triglyme is present. (105 Y. BARSHAD and E. GULARI, Chem. Eng. Commun., Refs.) 1986, 43, (1-31, 39-51 Forced concentration cycling during Fischer- Cyclodextrin-Palladium Chloride. New Tropsch syntheses over Ru/Al,O, changed the rate Catalytic System for Selective Oxidation and selectivity of the reaction. The rate of reaction to was improved by as much as 200% compared to the of Olefms Ketones steady state. Selectivity enhancement was quite com- A. HARADA, Y. HU and s. TAKAHASHI, Chem. Lett. Jpn., plex; under certain conditions significant increases 1986, (12), 2083-2084 were observed in ethane and propane selectivities. Terminal olefins are oxidised to ketones in high yields Prolonged exposure to CO was necessary for the for- under mild conditions using PdCl , and cyclodextrins mation of higher hydrocarbons. When CO pretreated as catalysts in two-phase systems. Separation of pro- Ru/Al,O, is exposed to H,, propane and higher ducts from catalysts or solvents is easy. Cyclodextrins hydrocarbons are produced first. show substrate selectivity. Platinum Metals Rev., 1987, 31, (2) 106 Rapid Thermal Hydrogen Production ELECTRICAL AND ELECTRONIC from Alcohols Catalysed by [Rh(2,2 I- ENGINEERING bipyridyl)* ] CI D. MORTON and D. J. COLE-HAMILTON, 3. Chem. SOL., The Ammonia Sensitivity of Platinum- Chem. Commun., 1987, (4), 248-249 Gate MOSFET Devices: Dependence on [Rh(bipy),] CI was found to thermally catalyse the Gate Electrode Morphology production of H, via the dehydrogenation of J. F. ROSS, I. ROBINS and 8. C. WEBB, sem. Actuators, propan-2-01, butane-2,3-diol, ethanol, and methanol. 1987, 11, (0, 73-90 The rates of H, production are dramatically higher The response to NH, of Si-based MOSFET devices than any previously observed system. Turnover with Pt gate electrodes has been studied. Devices numbers of 100hfor H, production were seen. with evawrated Pt gate electrodes, which are non- Ruthenium-Catalyzed Amidation of continuois are very NH, sensitive,.but devices with sputtered Pt gate electrodes which are continuous, Nitriles with hinee. A Novel, Facile are not NH, sensitive. Both devices show a similar Route to Amides and Polyamides response to H,, typically changes in threshold voltage S.-I. MURAHASHI, T. NAOTA and E. SAITO, 3. Am. of - -420mV and -35omV, respectively, to Chem. Soc., 1986, 108, (24), 7846-7847 500DDm H, at 150°c. ~ _- -~ A new method applicable for synthesis of various amides and polyamides is presented. It involves Ru Laser Direct-Write Metallization in Thin catalysed condensation of nitriles with amines in the Palladium Acetate Films presence of water to give the co~espondingamides M. E. GROSS, A. APPELBAUM and P. K. GALLAGHER, 3. and NH,. The reaction is clean and highly efficient Appl. Phys.,1987, 61, (4), 1628-1632 under neutral conditions, and is performed in a single Micron-scale Pd lines have been produced by a step, although the reaction temperature is high. photothermal laser direct-write process in thin pd RuH,(PPh,), was the most effective catalyst. acetate films. The range of observed structures relates Some Aspects of the Coordinations and to the complex thedprofiles generated by coupl- Catalytic Chemistry of Ruthenium ing of the incident laser radiation with the exothermic heat of reaction. Deviations of the electrical J. HALPERN, Are Appl. Chem., 1987, 59, (2), resistivities of the features from that of pure Pd result 173- I 80 from porosity in the lines. Among characteristic features of the co-ordination chemistry of Ru complexes containing a wide range of ligands is the propensity for intra- and intermolecular TEMPERATURE metallation of arenes and for the formation of polyhydride complexes. The roles of Ru polyhydride MEASUREMENT complexes in catalytic hydrogenation are discussed. Constant-Volume Gas Thermometry bet- Distinctive features of such complexes include ween 4K and lOOK catalytic hydrogenation of arenes and ketones. P. P. M. STEUR and M. DURIEUX, Metrobgia, 1986,23, (I), 1-18 FUEL CELLS Gas-thermometer measurements between 4-1ooK were performed in preparation for a revision of the Hydrogen Sulfide Poisoning of Platinum Ins. Gas-thermometer temperatures were com- Anode in Phosphoric Acid Fuel Cell Elec- pared between 13.8 and IOOKwith Pt resistance ther- trolyte mometers calibrated on IPTS-68, and between 4.2 D.-T. CHIN and P. D. HOWARD, 3. Electrochem. SOL., and 27.1K with Re-Fe resistance thermometers 1986, 133, (121, 2447-1450 calibrated on NPL scale of 1975. The effect of HIS on the anodic oxidation of HI on Pt in 94wt.% phosphoric acid fuel cell electrolytewas studied from 25-17oOC. Anodic IN curves of a sta- MEDICAL USES tionary Pt electrode were measured with a half-cell set Synthesis and Antitumour Activity of up in the presence of H ,S. Adding H ,S to H , caused a rapid decrease in the anodic current due to adsorp- Organometallic cis-Dichloro(enamine)- tion of H, S on Pt. The amount of H, S poisoning (amine)Platinum(II) Complexes decreased with increasing temperature and increased A. R. KHOKHAR, S. L. DORAN, D. B. BROWN and M. P. with increasing potential. Adsorbed H,S species HACKER, Inorg. Chim. Acta Bwimrg. Chem., 1987, blocked the active sites available for the adsorp- 135, (b18), (21, 81-83 tion/desorption of H and thus retarded the rate of H, A series of pt(I1) organometalliccomplexes have been oxidation on Pt. At sufficiently high anodic potentials synthesised and their in vivo anti-tumour activity has a layer of adsorbed S formed on the electrode surface been evaluated. Preliminary results indicate that this and suppressed the formation of Pt oxide at the 0 ad- class of complexes has good in vivo cytotoxicity sorption potentials. against L1210 murine leukaemia cells. Platinum Metals Rev., 1987, 31, (2) 107 NEW PATENTS METALS AND ALLOYS Shape Memory Alloy TOHOKU METAL IND. LTD. Magneto/Optical Storage Element Japanese Publ. Appl. 611217,544 SHARP K.K. European Appl. 192,256A Actuators operated at high temperatures, such as The element has a multi-layer structure including a steam regulation valves use Ti-Ni-Ru. reflective layer of Al-Ni alloy, or an alloy of Al with Pd, Pt, Cr or Mo. These alloys have a lower coeffi- Soft Palladium Manufacture cient of thermal conductivity than Al alone; therefore MITSUBISHI METAL K.K. recording sensitivity and quality of reproduction are Japanese Publ. Appl. 61l221,336 maintained. Pd bonding wire, used as a substitute for Au when assembling semiconductor equipment, is refmed by Reversible Hydrogen Storage zone melting Pd to a hardness of 5oHv or under. STANDARD OIL co. (OHIO) European Appl. 198,599A A reversible H, storage medium comprises an amor- phous metal alloy A,MbMf, where A is one or more CHEMICAL COMPOUNDS of Pd, Pt, Ag, Au and Hg, M is one or more of Ru, Dibenzalacetone Palladium Complexes Cu, Cr, Zn, etc., and Mf is one or more of C, Mg, Ti, rare earths, etc. A substantial portion of A is disposed CIBA GEIGY A.G. European Appl. 190,998A on the surface of the material. The composition can New Pd complexes are copolymerisable with epoxy be efficiently cycled without embrittlement. resin products and heat activated hardeners andlor curing catalysts for use as adhesives for example, but Multi Phase Cermet Compositions especially in the production of electrically conductive coatings and circuit patterns onto which metals can U.S. DEFT. OF ENERGY U.S. Patent 4,605,440 be deposited electrolessly. A B carbide4 cermet has at least four phases and its composition comprises these plus a /3 carbide-reactive metal component where the reactive metal is chosen ELECTROCHEMISTRY from Os, Pd, Pt, Ir, Rh, Ru, Se, Si, Sr, etc. A multiphase microstructure is produced with the Methane Production ceramic phases homogeneously distributed in the metallic phases and with strong adhesive forces at the GAS RES. INST. U.S. Patent 4,609,440 ceramiclmetal interfaces. CH, is produced by the electrochemical reduction of CO, in aqueous solutions, using a Ru cathode. Cur- Porous Fine Powder Production rent efficiencies of up to 30% can be achieved. ALLIED CORP. U.S. Patent 4,615,736 Electrolysis of Halide Solutions Ag, SaltsofPt, Pd, Ru, Rh, Au, Hg, Ir, Os, Re, As, STANDARD OIL CO. U.S. Patent 4,609,442 and their mixtures are used to produce fine metallic Halogens are generated from halide containing solu- powder by reduction under hypercritical temperature tions by using a cell containing an amorphous metal and pressure to form a fluid phase and the metal alloy with good electrochemical activity and corrosion powder, which is then separated off. resistance. The anode comprises preferably Permanent Magnet Manufacture Fe,,Ta,,Pt,, Ti,,Pt,,, Zr60Pt,u,etc. TOSHIBA K.K. Japanese Publ. Appl. 611156,706 Noble Metal Electrode A R-Fe-B alloy (where R is at least one of Y and rare- w. C. HERAEUS c.m.b.H. German Offen. 3,508,485 earths and Fe can be substituted by Ru, Rh, Pd, Ir, The electrode comprises a C particle-impregnated Os, Re, Co, Cr, Al, etc.) is ground into a grain size plastic, for example polyethylene, polypropylene, of 2-1opm, moulded in a magnetic field, sintered at PTFE or PVC, base covered with electrolytically 1000-12oo0C and cooled to 4ooOC at Io°C/min; the precipitated noble metal, of Ru, Rh, Pd, Ir andlor Pt. magnets produced have high magnetic flux density, The coating has good adhesion to the plastic and the high coercive force and a variety of uses. H, -embrittlement problem is overcome. Magnetic Recording Medium Electrode Prepation NEC CORP. Japanese Publ. Appl. 611204,914 OGRYZKO-ZHUKOVSKAYA Russian Patent 1,203, I30 The medium has a magnetic film made from an Fe- Electrodes for use in an electrolyser where H, is Nd alloy containing Pt and optionally Ti. It is evolved from water are made of Ti with 30% porosity prepared by sputtering in Ar on a glass base. The plated with a 2pm Pd coating which extends inside medium has perpendicular magnetic recording pro- the pores. The working life of the electrodes is in- perties and good corrosion resistance. creased 2.5 times. Platinum Metals Rev., 1987, 31, (2), 108-112 108 ELECTRODEPOSITION AND Metal Plating Process SURFACE COATINGS AGENCY OF IND. SCI. TECH. Japanese Publ. Appl. 611277,175 Coating for Glass Fibre The process for use with insulation printed circuit TORAY SILICONE K.K. European Appl. 192,275A boards, magnetic shielding, etc., involves depositing a The coating composition consists of (a) an Pd organosol dispersed in an organic solvent on the organopolysiloxane, (b) a vinylated polysiloxane, (c) article being plated, evaporating the solvent to form and organohydrogenpolysiloxane and (d) a Pt a Pd colloid on the article and then plating. catalyst. The compositions are used for coating op- tical fibres for long-distance communications, and ex- Tinted Coatings hibit high tensile strength. BAIKOV METALLURGY INST. Russian Patent I ,227,71I Evenly tinted corrosion- and wear-resistant coatings Ruthenium Chalcogenide Thin Film for jewellery, optical mechanisms, etc., are made by CNRS CENT. NAT. RECH. SCI. depositing In onto a Pd-In substrate. The tints are a World Parent APP~.8615,824 range of colours from lemon to violet. Doped Ru sulphide, selenide or telluride are formed as a thin film-by chemical vapour deposition using organometallic Ru derivatives. Products can be used LABORATORY APPARATUS in the semiconductor industry, especially in hostile AND TECHNIQUE environments and for passivation. Chemical Detector Ceramic Metallisation MINNESOTA MINING MFG. CO. AGENCY OF IND. SCI. TECH. European Appl. I 95,648A Japanese Publ. Appl. 611146,778 The detector comprises a photoluminescent semicon- Ceramics are metallised by coating with a mixture of ductor having a metal, preferably Pd, coating on a Cu salt (CuCO,, CuSO,, CuS, CuO, CuCI,), SiO, radiation emitting surface, the height of the Schottky andlor kaolin and at least one of Pd, Pd oxide, or Pt barrier of the diode varying when H, is absorbed by chloride, by heating at go0-13m0C in an oxidising the metal layer; a source of actinic radiation and a atmosphere, and then reducing. The metallisation means for detecting changes in the radiation emitted layer has adhesive strength and chemical resistance. from the surface. Surface Activation of Glass Fibre Pressure Transmitting Device NITTO BOSEKI K.K. Japanese Publ. Appl. 61/186,250 TOSHIBA K.K. Japanese Publ. Appl. 611194,326 A glass fibre surface is activated by applying a liquid A pressure differential transmitting device includes a containing Ti coupling agent and dibenzonitrile Pd diaphragm which consists of a thin sheet of elastic chloride, and then reducing the fibre to deposit Pd metal to detect the pressure of a fluid. The sheet is an nuclei to act as a metal plating catalyst. The fibre can alloy of formula (M-M')TbY, where M is Fe, Co or be electrolessly coated and has bond strength. Ni, M' is Pd, Rh, Ir, Pt, Re, W, etc., and Y is Si, B, P, etc. The device is lightweight and has good en- Plastic Antistatic Treatment vironmental and corrosion resistance. HITACHI K.K. Japanese Publ. Appl. 611190,goo Plastic surfaces are rendered antistatic by forming a Optical Hydrogen Sensor sputtered film of conductive mateiial, such as Pd, AGENCY OF IND. SCI. TECH. Au, stainless steel, SnO, , etc. Sputtering lowers the Japanese Publ. Appl. 611204,545 electrical resistance of the surface. The sensor is comuosed of (a) a substrate with a monolithically embedded optical waveguide, (b) a Palladium Coatings on Steel light-absorbing layer formed on the waveguide area of MITSUBISHI MOTOR CORP. the substrate and composed of a dielectic substance Japanese Pub/. APPl. 611201,781 with dissociated H, part of which may be Ir(OH)", Excess urea is added to PdCI, to prepare aqueous Rh,O,.xH,O, WO,, MOO,, V,O,, TiO,, heptyl solutions of pH 2-3, and then clean steel is immersed viologen, etc., and (c) an absorbing layer capable of therein, removed. dried and fixed to coat Pd onto the dissociating adsorbed H, , for example Pd or Pt. steel which now. has improved heat and oxidation resistance. Moisture Content Probe ERN0 RAUMFAHRTECH G.m.b.H. Plating Hydraulic Cement German Offen. 3,510,379 DENKI KAGAKU KOGYO K.K. A probe for measuring moisture content in a Japanese Publ.APPl. 611210,182 substance has a carrier with a Pt resistance Cement material is surface activated with a platinum temperature sensor mounted on it. The output signal group metal compound in a bath to produce a is dependent upon the thermal conductivity of the catalytic layer, and is then plated electrolessly with substance, and one example of use is for plant- Cu, Ni, Cr, Co, Sn, Ag or Au, etc. rearing-chamber nutritive media. Platinum Merals Rev., 1987, 31, (2) 109 Galvanic Gas Humidity Sensor Catalytic Combustion of Light BELORUSSIAN LENIN UNIV. Russian Patent 1,223,120 Hydrocarbon The sensor contains an electrochemical cell with a NIPPON SHOKUBAI KAGAKU European Appl. 198,948A solid electrolyte and two platinised metal grid elec- I-4C Hydrocarbon fuels are combusted using a two trodes covered in Pt black. Crystal hydrates with or stage noble metal catalyst system. The fmt stage without an anhydrous compound are placed in the catalyst comprises Pd/Pt or Pd/Pt/NiO and effects cell, and Cr dihydro-tripolyphosphateis used as the sufficient combustion to give a temperature high solid electrolyte. The sensor determines the relative enough to induce secondary combustion with Pt or humidity of a gas from -20 to I~OC. Pt/Pd. CH, can be burned without emission of CO, NO, or hydrocarbons. HETEROGENEOUS CATALYSIS One Step Esterification Optical Fibre Cable STANDARD OIL co. (OHIO) European Appl. 199,530~4 TELEPHONE CABLES LTD. British Appl. 2,172,410A The process under mild reaction conditions, involves The cable has H,-trapping powder, such as Pd/C, reaction with 0, in the presence of a Pd based in- running longitudinally within the protective cover to termetallic catalyst, such as PdTe,,, Zno,z, sup- catalyse the reaction of H, and 0, to form H,O, and ported or unsupported. The aldehyde is preferably it is mixed with H,O-sorbent or blocking substance. (meth)acrolein and the alcohol is preferably The powder is supported on a tape to prevent its in- methanol. terference with the movement of the fibres. Deuterated (Meth)acrylic Acid Pro- duction Preparation of Oxalic Acid Diester MITSUBISHI RAYON K.K. European Appl. 203,588A ROHM G.m.b.H. British Appl. 2,173,794A (Meth)acrylic acid is deuterated directly by exchange Diesters of oxalic acid are prepared by oxidative car- of H in the presence of a catalyst, preferably Pd, Ru, bonylation of an alcohol at a pressure of 1-700 atm Ir, Rh or Pt or their compounds at 60-20o0C. The and at 20-250°C in the presence of a catalyst system resultant acids can be esterified to give deuterated comprising Pd, at least one metal halide and activated (meth)acrylates for use in the production of low light charcoal. High yields are obtained over short times. loss optical fibres. Ammonium Nitrate Removal from Waste Hydrogen Production Water PHILLIPS PETROLEUM CO. U.S. Patent 4,602,988 OSAKA GAS K.K. European Appl. 196,597A H, is produced from alkaline aqueous solvents of Treatment is effected by contacting waste water with H,S by irradiation with light at 300-700 nm in the a supported catalyst of Ru, Rh, Pd, Os, Ir, Pt or Au presence of catalytic amounts of ZnO-RuO,, ZnO, at 100-370~Cand pH 3-11.5, in order to oxidise the ZnS, ZnSe or CuGaS,. NH,. The process is especially applicable to waste water from U processing, or reprocessing U fuel. Dehydrogenation Catalyst UOP INC. U.S.Patent 4,608,360 Ethanol and Propanol Production A catalyst for paraffm dehydrogenation comprises Pt, BP CHEMICALS LTD. European Appl. 198,681A Pd, Ir, Rh, Os, Ru, a co-formed Group IVA metal, The preparation is achieved by vapour phase such as Ge, Sn, or Pb, and an alkali(ne earth) metal, hydrogenation of acetic or propionic acid over a for example Cs, Rb, K, Na, etc., on an Al,O, sup- catalyst comprising a Group VIII metal, preferably port. The products can be used in the manufacture of Pd or Ru, and Re/C or/SiO, . High long lasting activi- detergents, high octane petroleum, pharmaceuticals ty and selectivity are attained at 1-150 bar. and plastics. Propylene Acetoxylation Catalyst Alcohol or Ester Preparation PHILLIPS PETROLEUM CO. U.S. Patent 4,608,362 B.P. CHEMICALS LTD. European Appl. 198,682A The catalyst comprises K, Bi and Pd on a support, The preparation involves contacting a 2-12C carbox- together with Rh as a promoter. Acetoxylation of pro- ylic acid at increased temperature and pressure with pylene is effected with higher selectivity, conversion HI in the presence of a heterogeneous catalyst com- and space time yield. prising-- Mo or W and preferably.. Pd, Rh or Ru. Methane Production Reforming Catalyst DOW CHEMICAL CO. U.S. Patent 4,609,679 CHEVRON RESEARCH CO. European APPl. 198,721A High methane yields from synthesis gas are effected The catalyst comprises a large-pore zeolite containing using a supported Ru catalyst along with at least one 1.atomic proportion of Pt and at least 0. I atomic pro- oxide of Ta, Nb or V. The calcination temperature portions of promotor metal, consisting of at least one during support production is such that no crystalline of Fe, CO and Ti. The catalyst is highly active and metal oxide is detectable by X-ray diffraction before selective for dehydrocyclisation. Ru deposition. Platinum Metals Rev., 1987, 31, (2) 110 Staging Reforming Catalysts HOMOGENEOUS CATALYSIS EXXON RES. & ENG. CO. U.S. Patent 4,613,423 The octane quality of a naphtha is improved by refor- Methanol Conversion Catalyst ming in the presence of H, in a reforming unit com- BRITISH PETROLEUM P.L.C. British Appl. 2,171,924A prising several reactors in series, with a Pt or PtIRe A catalyst for converting syngas to methanol has for- catalyst in each. The catalyst of the last reactor con- mula M,ThAbO, (I), where M is at least one of Pd, tains Pt and Re and sufficient Ir to increase the 5C + Pt and Ag, preferably Pd, and A is alkali metal. The liquid yield. production of a precursor to (I) is also claimed. Hydroisomerisation Catalyst Pd(I1)IPPh Containing Catalyst MOBIL OIL CORP. U.S. Patent 4,615,997 SHELL INT. RES. Mii. B.V. European Appl. 194,707A The catalyst containing a highly dispersed noble A catalyst used in the hydrocarboxylation of alkynes metal, preferably Pt, Pd, Os, Re or Ru and compris- with enhanced reaction rates and high selectivity ing a zeolite of Constraint Index <2, and a binder, is comprises a divalent Pd compound and a tri-organic prepared by (a) incorporating noble metal with the phosphine (11). The reaction is with CO and carbox- zeolite and binder (b) calcining and (c) contacting ylic acid in the liquid phase. with a stream of inert gas containing C1, . The catalyst is used for low pressure isomerisation of paraffin. Aldehyde Production Engine Exhaust Filter SOC. CHIM. CHARBONNAGES TOYOTA J1WsHAK.K. Japanese Publ. Appl. 61/146,314 World Patent Appl. 8615,415A A filter for removing C particles from engine exhaust A catalyst system for the production of aldehydes consists of a honeycomb cordierite base with Pd comprises: (a) a Pt complex LPtX, , L is an organic and/or Rh catalysts and alkali metal oxide(s) compound containing at least 2 P atoms, X=halogen, deposited on it. C particles are trapped and burned at (b) a complex combination of Sn and an alkylene car- a combustion efficiency of 85%. bonate. Aldehydes are produced by the hydrofor- mylation of an ethylenically unsaturated compound I.C.E. Purification Catalyst with a mixture of CO and H, . NISSAN CHEM. IND. K.K. Japanese Pu bl. Appl. 6 I, I 97,03 8 1 -4C Alkanol Production The catalyst consists of a monolithic support carrying TEXACO INC. U.S. Patent 4,622,343 a catalyst of GO,, Pr,O,,, a platinum group metal Synthesis gas is contacted at a pressure of at least 30 and activated Al, 0 preliminarily loaded with Ce. It atm and at least 150Oc with a trimetallic catalyst com- can remove hydrocarbons, CO and NO, prising compounds of Ru, Co and Mn dispersed in a simultaneously. low melting quarternary phosphonium salt. Waste Gas Purification Catalyst MATSUSHITA ELEC. IND. K.K. FUEL CELLS Japanese Publ. Appl. 611230,737 Fuel Cell Electrodes The catalyst consists of a glass fibre sheet whose SiO, ELEC. POWER RES. INST. INC. U.S. fktent 4,610,938 content is increased above 95% by acid- or heat- Improved performance with acid electrolyte treatment, and a layer of inorganic oxide, which is H ,PO, fuel cells is obtained by coating the PtIC electrode mainly -y-Al,O, where Pt andlor Pd, and TiO, are with a perfluorinated acid-containing addition supported the surface. It can be used for clarifying on polymer. waste gas from domestic petroleum heaters. Supported Catalyst Preparation Catalyst for Fuel Cells HOECHST A.G. Geman Offen. 3,533,250 UNITED TECHNOLOGIES CORP. U.S. Patent 4,613,582 The catalyst for exhaust gas purification, hydrogena- A ternary metal alloy catalyst for fuel cell electrodes, tion and isomerisation reactions is produced by ap- and for other uses, which increases the work done by plying Ru, Pd, Rh, Ir or Pt onto a ceramic a fuel cell is formed from a finely divided noble metal, honeycomb provided with an A,O, layer. The preferably Pt/C black, with Co and transition metal honeycomb is soaked in aqueous NH solution and at compound solutions, followed by reduction in N, . least one noble metal salt, dried and tempered. Production of Hydroxylamine Sulphate GLASS TECHNOLOGY GRODNO MOT COMBINE Russian Patent 1,214,584 Press-Mould for Glass N oxide is reduced with H, in a 6-vessel cascade reac- MATSUSHITAELEC. IND. K.K. EuropeanAppl. 191,618A tor using a reaction medium of 18.5-20.0% H,SO, Glass optical elements are press-moulded from in the presence of a catalyst of 0.3-0.5% Pt/graphite. softened glass using two moulds made from a high Fresh catalyst is added continuously and spent heat resistant base coated with a film of Ir, Ru, an catalyst removed regularly for regeneration and alloy of Ir with Pt, Ru, Os, Rh or Re, or an alloy of recycling. Ru with Pt, Ru, Os, Rh or Re. Platinum Metals Rev., 1987, 31, (2) 111 Optical Glass Mould The Conjugation of Metallothionine to MATSUSHITA ELEC. IND. K.K. Bioactive Molecules Japanese Publ. Appl. 611146,724 DU POWDE NEMOURS co. European Appl. 196,669A Pressure shaping surfaces for high accuracy optical The production involves conjugating a bioactive glass are coated with a thin membrane comprising an molecule, such as an antibody or fragment, steroid, alloy of Pt, Ir, Os, Pd, Rh, Ru and a B compound, hormone, prostaglandin, etc., to a heterobifunctional such as TiB,, ZrB,, NiB,, Fe,B, etc. crosslinker and then conjugating the product with the metallothionine, the metal of which may be a non- ELECTRICAL AND ELECTRONIC tracer such as Ru, Pt, Bi, Pb, Hg, Au, etc., or at least a part-exchanged tracer, Ru9', Pd"', Hg"', Pb"', ENGINEERING Ag'll, Aul", etc. The conjugate is useful in diagnosis Electrochromic Element and radiotherapy. N1PPONKOGAKUK.K. JapanesePubl. Appl. 611144,630 Preventing Bone Calcium Resorption The element consists of an opaque electrode, a reduc- SLOAN-KETTERINC INST. European Appl. 201,804A tively colouring electrochromic layer, a transparent The treatment consists of the administration of a ion-conductivelayer and opposite electrode, the latter suitable metal-containing compound, such as Ga comprising a dispersed phase of metal or Ir (hydr)ox- acetate, nitrate or fluoride, diamminedichloro Pt(II), ide and transparent solid electroconductive disper- cis-diammine-1,I-cyclobutane dicarboxylate Pt(II), sion medium. etc. Slide Contact Device X-Ray Emitting Implant TANAKA KIKINZOKU KOGYO NUCLEAR MED. INC. World Patent Appl. 8614,248A Japanese Publ. Appls. 611156,648-78 A particle for in vivo tumour-implantation contains The device comprises a brush and commutator or slip Pd enriched in Pd lo2 . This is activated by exposure to ring. The brush is of alloy comprising, in wt.%: neutron flux giving a fraction of X-ray-emitting 68-72Au, 3-7Pt, 8-12Ag, 12-16Cu and 0.1-2Ni; Pd lo]. The particle is non-toxic and biocompatible, 20-7oPd and 30-8oAg; or 32-38Pd, 8-12Au, and facilitates localised exposure. 8-12Pt, 27-33Ag, 12-16Cu and 0.1-2Zn, etc. The device has less wear and a stable, but low contact Implantable Corneal Prosthesis resistance. Addition of C improves wear resistance. T. C. WHITE U.S. Patent 4,612,012 An implantable corneal prosthesis comprises a len- Platinum Resistance ticular transparent central portion and a peripheral SHARP K.K. German Offen. 3,603,784 portion with an outer tissue-contacting surface, A resistance for temperature measurement comprises preferably such as Pt, Au or polymer. All parts must an insulating substrate coated with a Pt film and then be biologically compatible. a thin protective Al ,0, film possessing high thermal conductivity, chemical stability, heat resistance Malonato Pt (11) Complexes stability and electrical insulation. JERUSALEM UNIVERSITY U.S. Patent 4,61431 I The complexes with anti-tumour activity are of for- mula L,Pt(II)(OCO),CH-NH, where L is a mono- MEDICAL USES or bidentate amine ligand. The complexes are Platinum Anti-Cancer Complexes chemically stable and can be injected intravenously. YEDA RES. & DEV. co. LTD. European Appl. 190,464A Blood Gas Sensor Complexes of Pt compounds, such as K,PtCI,, cis- SUMITOMO ELEC. IND. K.K. platin, diaquodiammine Pt nitrate and a Japanese Publ. Appl. 611128,945 physiologically acceptable macromolecular carrier, The sensor has an electrode component made of con- for example a polysaccharide, or a polyamino acid are centric electrodes comprising a pH electrode, a noble useful in anti-tumour treatment. Pt is released metal electrode, preferably Pt or Au and an AglAgQ gradually in vivo thus reducing toxicity. Pt targeting electrode, which is between the first two. can use anti-tumour antibodies as carriers. Simultaneous accurate determination of blood 0, Optical Sensor for Oxygen Monitoring and CO, by skin application is possible. COULD INC. European Appls. 190,829130A New Anti-Oncotic Organic Pt Compounds An extremely small monitoring device, which AJINOMOTO K.K. Japanese Publ. Appl. 6111 52,625 responds to light, comprises an optical waveguide, an Pt(I1) complexes with I ,S-cyclooctadiene and 0-sensitive medium preferably including a phenan- cyclooctene-5-yl-acetic acid derivatives show growth throline salt of Ru(I1) perchlorate, which fluoresces inhibitory action to cancer and leukaemia cells. in response to light, where fluorescence is dependent on 0, partial pressure. The device gives rapid, ac- curate, precise measurement for remote sensing, for The New Patents abstracts have been prepared from example in arteries, blood vessels or catheters. material published by Dement Publications Limited. Platinum Metals Rev., 1987, 31, (2) 112