Platinum Metals Review - Volume 24, Issue 2, 1980

The potential advantages of ruthenium plating are becoming increasingly appreciated in the electrical contact field. By comparison with rhodium, electrodeposited ruthenium is much less costly and possesses very similar properties of extremely high hardness and resistance to corrosion but with superior resistance to wear; while the dramatic increase in the price of gold has further emphasised the importance of evaluating its merits of low contact resistance and much lower density, offering great economy for a given thickness of deposit.

Aryl, heterocyclic, benzyl, and vinylic halides undergo facile reactions with carbon monoxide or olefins forming new carbon-carbon bonds under the influence of triarylphosphine-palladium catalysts. The carbon monoxide reactions produce esters in the presence of alcohols, amides in the presence of amines, and aldehydes in the presence of hydrogen. Reactions with olefins produce new olefins in which a vinylic hydrogen is replaced by the organic group from the halide. Some olefins and vinylic halides require the presence of secondary amines to react, in which instance tertiary allylic amines are formed catalytically. Conjugated dienes may be used in place of simple olefins to form products with additional unsaturation. Numerous applications for these reactions in organic synthesis appear likely.

The availability of a complete and accurate phase diagram is an essential requirement if a full understanding of the properties, and hence the potential applications, of an alloy system is to be gained. Although the general nature of the tungsten-platinum constitutional diagram has been known for many years, it is now apparent that intermediate phases which are not incorporated in the published phase diagrams may exist, and evidence to support this is presented.

The history of the powder metallurgy of platinum may well be claimed to be the history of powder metallurgy itself. For very many years all the malleable platinum used in industry was made by this process, developed independently in Spain, in England and in Russia. The author outlines the struggles of the early workers in this field and discusses the cause of the cracking which they occasionally reported.