ISSN 2056-5135 JOHNSON MATTHEY TECHNOLOGY REVIEW Johnson Matthey’s international journal of research exploring science and technology in industrial applications Volume 59, Issue 3, July 2015 Published by Johnson Matthey www.technology.matthey.com © Copyright 2015 Johnson Matthey Johnson Matthey Technology Review is published by Johnson Matthey Plc. All rights are reserved. Material from this publication may be reproduced for personal use only but may not be offered for re-sale or incorporated into, reproduced on, or stored in any website, electronic retrieval system, or in any other publication, whether in hard copy or electronic form, without the prior written permission of Johnson Matthey. Any such copy shall retain all copyrights and other proprietary notices, and any disclaimer contained thereon, and must acknowledge Johnson Matthey Technology Review and Johnson Matthey as the source. No warranties, representations or undertakings of any kind are made in relation to any of the content of this publication including the accuracy, quality or fi tness for any purpose by any person or organisation. www.technology.matthey.com JOHNSON MATTHEY TECHNOLOGY REVIEW www.technology.matthey.com Johnson Matthey’s international journal of research exploring science and technology in industrial applications Contents Volume 59, Issue 3, July 2015 174 Selected Electrical Resistivity Values for the Platinum Group of Metals Part I: Palladium and Platinum By John W. Arblaster 182 12th Greenhouse Gas Control Technologies Conference A conference review by Christopher Starkie 188 Platinum Group Metal and Washcoat Chemistry Effects on Coated Gasoline Particulate Filter Design By Chris Morgan 193 “Additive Manufacturing Technologies: 3D Printing, Rapid Prototyping, and Direct Digital Manufacturing”, 2nd Edition A book review by Jonathan Edgar and Saxon Tint 199 Temperature Dependent Heat Transfer Performance of Multi-walled Carbon Nanotube- based Aqueous Nanofl uids at Very Low Particle Loadings By Meher Wan, Raja Ram Yadav, Giridhar Mishra, Devraj Singh and Bipin Joshi 207 The Effects of Hot Isostatic Pressing of Platinum Alloy Castings on Mechanical Properties and Microstructures By Teresa Fryé, Joseph Tunick Strauss, Jörg Fischer-Bühner and Ulrich E. Klotz 218 “Exploring Materials through Patent Information” A book review by Julia O’Farrelly 221 “Urea-SCR Technology for deNOx After Treatment of Diesel Exhausts” An essay book review by Martyn V. Twigg 233 Sintering and Additive Manufacturing: The New Paradigm for the Jewellery Manufacturer By Frank Cooper 243 Introduction to the Additive Manufacturing Powder Metallurgy Supply Chain By Jason Dawes, Robert Bowerman and Ross Trepleton 257 Atomic-Scale Modelling and its Application to Catalytic Materials Science By Misbah Sarwar, Crispin Cooper, Ludovic Briquet, Aniekan Ukpong, Christopher Perry and Glenn Jones 284 In the Lab: Combining Catalyst and Reagent Design for Electrophilic Alkynylation Featuring Professor Jérôme Waser 287 Johnson Matthey Highlights http://dx.doi.org/10.1595/205651315X688091 Johnson Matthey Technol. Rev., 2015, 59, (3), 174–181 JOHNSON MATTHEY TECHNOLOGY REVIEW www.technology.matthey.com Selected Electrical Resistivity Values for the Platinum Group of Metals Part I: Palladium and Platinum Improved values obtained for liquid phases of palladium and platinum John W. Arblaster The measured electrical resistivity (ρ) usually consists Wombourne, West Midlands, UK of a temperature dependent intrinsic resistivity, ρi, which is due to the pure metal and is caused by the Email: [email protected] scattering of the charge carriers (electrons or holes) by phonons (quantised vibrations of the lattice) and by their collisions with each other, and a residual resistivity Electrical resistivity values for both the solid and liquid (ρ0) due to impurities which also scatter the carriers and phases of the platinum group metals (pgms) palladium increase the resistivity. The quantity ρ0 is considered to and platinum are evaluated. In particular improved be a summation of the effects of different impurities and values are obtained for the liquid phases of these is also considered to be temperature independent. The metals. Previous reviews on electrical resistivity which two contributions to the total resistivity are combined included evaluations for the pgms included those of according to Matthiessen’s Rule: ρ = ρ0 + ρi and because Meaden (1), Bass (2), Savitskii et al. (3) and Binkele ρ0 may vary from sample to sample then attempts are and Brunen (4) as well as individual reviews by Matula made to evaluate values of ρi which should be universal (5) on palladium and White (6) on platinum. for a specifi c metal. 1.1 Correction for Thermal Expansion Effects 1. Introduction In order to obtain a reference value to which all other Electrical resistivity (ρ) is defi ned in terms of the measurements are adjusted the electrical resistivity is International System of Units (SI units) as: evaluated at 273.15 K (0ºC). In the low temperature region below about 30 K the ρ = R A / l (i) 2 5 resistivity can be represented by ρ = ρ0 + A T + B T where where the temperature dependent terms represent R is the electrical resistance of a uniform specimen of the intrinsic resistivity, whilst up to room temperature material in ohms (Ω) the experimental values are generally given in such A is the cross-sectional area of the specimen in square a form that interpolation can be achieved by using metres (m2) simple polynomials rather than using the complicated l is the length of the specimen in metres (m) Bloch-Grüneisen formula (7–9). In the defi nition The units of ρ are therefore Ω m although practically of resistivity as ρ = R A / l then A and l are usually the most useful units are μΩ cm. measured at room temperature and therefore at different 174 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X688091 Johnson Matthey Technol. Rev., 2015, 59, (3) temperatures both A and l have to be corrected for have been superseded by the later high precision thermal expansion effects. It is found below room measurements of Williams and Weaver (15) (0 K–300 K) temperature that for the level of accuracy given for ρ, and Khellar and Vuillemin (16) (17 K–300 K), with the thermal expansion corrections are generally negligible latter given only in the form of an equation which was but at higher temperature the measurements have to evaluated at 17 K and then at 10 K intervals from 20 K be corrected, especially if they are based entirely on to 270 K. The measurements of Williams and Weaver the room temperature values for A and l which are were interpolated above 100 K so as to also obtain a usually measured at 293.15 K, the accepted reference full evaluation at 10 K intervals from 20 K to 270 K. temperature for length change measurements: The measurements of Schriempf and of Williams and Weaver agree satisfactorily and were averaged to 10 K ρ (corrected) = ρ (uncorrected) [(A / A ) × (l / l )] (ii) T 293.15 293.15 T with the measurements of Williams and Weaver being extended to 16 K. The measurements of the latter = ρ (uncorrected) [1 + (lT – l293.15) / l293.15] (iii) and of Khellar and Vuillemin do not agree below 35 K. where Equation (iii) can be considered to be a close However the equation of Khellar and Vuillemin showed approximation of Equation (ii). However since 273.15 K peculiar behaviour below this temperature with derived is the actual reference temperature then corrected values being 6% higher than those of Williams and values of ρ(T) should be further corrected for thermal Weaver at 17 K but 31% lower at 20 K. Therefore the expansion from 293.15 K to 273.15 K. Since this latter measurements were given preference up to 35 K. correction is usually negligible at the level of accuracy At this temperature and above values from the two sets given then it is not applied. of measurements were averaged. Overall agreement In the case of rapid pulse heating to high temperatures, is to within 0.5% between 60 K and 180 K and to within because of inertia l generally is unaltered and it is A 0.1% above 180 K. The selected values of Matula that changes. If D is the diameter of the wire then: below 273.15 K are based on a combination of the measurements of White and Woods and of Laubitz and ρ (T) = ρ (measured) (D 2 / D 2) = ρ (measured) (V / V ) T 293.15 T 293.15 Matsumura and on average the intrinsic values show a (iv) bias of 0.02 μΩ cm above the more recently selected where VT is the volume of the sample at temperature values. Other measurements in the low temperature T and V293.15 is the volume at 293.15 K. These are region were discussed by Matula. 2 2 essentially DT and D293.15 respectively since l is In the high temperature region Matula (5) selected assumed to be unaltered. only the measurements of Laubitz and Matsumura (14) (90 K–1300 K). After correction for ρ0 = 0.020 μΩ cm 2. Palladium the values were calculated at 50 K intervals from 350 to 1300 K. In the present evaluation these measurements Palladium has a face-centred cubic structure and were combined with the more recent measurements of the melting point is a secondary fi xed point on the Khellaf et al. (18) (295 K–1700 K) which were given in International Temperature Scale of 1990 (ITS-90) at the form of an equation which was also evaluated at 1828.0 ± 0.1 K (10). 50 K intervals but over the range 350 K to 1750 K. After correction of both sets of measurements for thermal 2.1 Solid expansion using the values selected by the present Electrical resistivity values for solid palladium at author (19) they were fi tted to Equation (v) which 273.15 K are given in Table I.