Platinum Metals Review - Volume 54, Issue 3, 2010

One of the recurrent challenges in catalysis is how to ensure that the right reactions take place. In a recent collaborative programme between academic and industrial partners, some of the key issues relating to reactant specificity and product selectivity in liquid and gas media have been tackled using a combination of computational modelling, catalyst chemistry and chemical engineering. As well as providing solutions to several real-life problems from the chemical manufacturing industry, essential skills required for in situ studies have been established within the academic centres during the course of the programme. These developing skills are intended to have an ongoing impact on the understanding and application of complex multiphase processes, in which platinum group metals and other precious metals are often present as catalysts.

Analysis of the non-patent scientific literature can be used to reveal trends in platinum group metals (pgms) research. In this article, a study was carried out using the Chemical Abstracts database on key terms related to the pgms for the years 1998 and 2008, revealing an increase in research during this time period across most of the pgms both globally and especially in China. Platinum and ruthenium showed the most growth with areas such as nanotechnology and magnetic memory becoming particularly significant for ruthenium. In China, the fields of electrochemistry, and energy conversion technologies including fuel cells, were among those showing growth.

Ultrasonic attenuation for the longitudinal and shear waves due to phonon-phonon interaction and due to thermoelastic relaxation mechanisms have been evaluated in bimetallic alloys of the coinage metals (copper, silver or gold) with 1, 2, 3 or 4 at% platinum. The evaluations were carried out along the 〈100〉, 〈111〉 and 〈110〉 crystallographic directions at room temperature. Second- and third-order elastic constants, ultrasonic velocities and thermal relaxation times have also been computed for these alloys. In each case, the addition of platinum to the coinage metal reduces the attenuation, which indicates that bimetallic alloys with a higher platinum content are more ductile and stable and contain fewer defects in their crystal structure than those with a lower platinum content. The predominant mechanism of attenuation of ultrasonic waves is phonon-phonon interaction rather than thermoelastic loss. The results are compared with available theoretical data and experimental measurements for the pure coinage metals. These results, in combination with other well-known physical properties, can be applied to the non-destructive testing of materials for various industrial applications.

The platinum group metals (pgms) are characterised by their high melting points and resistance to corrosion. The glass industry most commonly uses platinum, platinum-rhodium alloys and, recently, iridium. These protect a variety of components and ceramic substrates used in glass manufacture from erosion by molten glass, including thermocouples, furnace and forehearth parts. This protection takes the form of a fabricated part or a coating applied to a substrate. Glass manufacturers use these pgm products to get financial benefits, such as increased output, reduced downtime, extended equipment life, shape retention of ceramic parts and fewer defects in the end product. Another important advantage is that pgms are recyclable: as with glass, precious metals can be recycled, melted and reused indefinitely. In addition to these advantages, a choice of pgm-based technologies is available to the industry and this flexibility ensures that both protection and metal use can be optimised.