Platinum Metals Review - Volume 46, Issue 2, 2002

Palladium complexes bearing N-heterocyclic nucleophilic carbenes can function as efficient and convenient mediators of C-C and C-N cross-coupling reactions. These phosphine-free systems are highly effective in coupling reactions of aryl bromides and aryl chlorides with a variety of coupling partners. Some applications of these Palladium complexes in a range of coupling reactions are described here and catalysts, conditions and results are presented.

The performance of precious metal alloys can be usefully compared by the application of engineering design theory and heat flow properties on the small scale that is required for jewellery production. Some of the physical and mechanical properties of Platinum jewellery alloys differ sufficiently from typical gold and silver alloys to require modifications in the processing techniques, but these properties may allow for stronger slender designs. The thermal diffusivity of Platinum jewellery alloys is significantly lower than that of other precious metal jewellery alloys. This explains why laser welding is so efficient when used in making platinum jewellery and why it also allows most of the cold work hardening to be retained in components.

A new class of alloys based on platinum group metals, which are called refractory superalloys, is proposed. These refractory superalloys have a f.c.c. and Ll2 coherent two-phase structure (similar to that of nickel-based superalloys), high melting temperatures, and good potential as structural materials for use at temperatures up to 1800°C. In this paper, we report our results on the strength behaviour, creep property, ductility and fracture mode of iridium-based refractory superalloys.