Alloys containing platinum group metals

Gold occurs as an alloy with copper, nickel and platinum group metals. Typically contains low amount of gold... 

Because of the high activity of palladium in electrocatalysis, palladium-based alloys, which contain one or more platinum-group metals along with titanium as well as boron and/or silicon, have been thoroughly investigated. 

The platinum-group metals (Ru, Os, Rh, Ir, Pd and Pt) are rare (Figure 23.1) and expensive, and occur together either native or in sulfide ores of Cu and Ni. Three sites of mineral deposits in the former Soviet Union, Canada and South Africa hold the world s reserves. The main source of ruthenium is from wastes from Ni refining, e.g. from pentlandite, (Fe,Ni)S. Osmium and iridium occur in osmiridium, a native alloy with variable composition 15-40% osmium and 80-50% iridium. Rhodium occurs in native platinum and in pyrrhotite ores (Fei S, n = 0-0.2, often with <5% Ni). Native platinum is of variable composition but may contain as much as 86% Pt, other... 

Most important mineral Osmium is a PGM (platinum group metal). It is mainly found alloyed with other platinum metals, from which it is recovered commercially. In the South African Merensky Reef and the Canadian Sudbury and Russian Norilsk deposits, the osmium content (relative to the total PGM quantity) is about 1 %. A special naturally occurring alloy is osmiridi-um containing, for example, 50% iridium, 25% osmium, with other PGMs making up the total. 

Kumagai K., Samata Y., Kawashima A., Asami K. and Hashimoto K. (1987) Anodic characteristics of amorphous nickel-valve metal alloys containing small amounts of platinum group elements in 0.5 M NaCl. J. appl. J. electrochem. 17, 347-356. 

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