Platinum Metals Review - Volume 20, Issue 3, 1976

The presence of a platinum metal enhances the ability of hydrogen, carbon, carbon monoxide and organic vapours to reduce the more stable refractory oxides. Such reactions, which may start at temperatures as low as 600°C, occur because of the high affinity of the platinum metals for the metal of the refractory oxide and result in the formation of intermetallic compounds or stable solid solutions. This account, based on experimental studies which yielded useful information on the thermodynamic behaviour of platinum metal alloys, presents results which should assist in preventing damage to industrial platinum apparatus. It also suggests that metals could be brazed to refractory oxides using a platinum containing brazing alloy under suitable reducing conditions.

This article describes the properties and characteristics of a new addition to the range of platinum-based alloys for high-temperature structural use, known commercially as ZGS 10 per cent rhodium-platinum. The processes developed at the Johnson Matthey Research Centre for the introduction of a highly dispersed non-metallic phase into pure platinum, outlined in a previous article in this journal, have now been further optimised to a stage where a similar strengthening dispersion can be produced within a rhodium-platinum alloy matrix. The resulting material is significantly stronger and more creep resistant than the conventional high-temperature rhodium-platinum alloys, while retaining the useful electrical and chemical properties that have made these alloys so attractive as materials of construction in many industrially important areas.

Among the papers presented at the Dalton Symposium held during the Annual Congress of the Chemical Society in Glasgow were contributions concerned with the use of the platinum group metals as heterogeneous and homogeneous catalysts and with recent developments concerning the molecular structure of some osmium and ruthenium complexes.