The Affinity of the Platinum Metals for Refractory Oxides

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.