Platinum Metals Review - Volume 45, Issue 2, 2001

The United States motor vehicle emission control programme is noted for its pioneering role and success in limiting exhaust pollution, utilising the three-way catalyst, cleaner fuels, improved engine design and calibration strategies. The progressive lowering of the emission limits by technology-forcing legislation via the agencies of the U.S. Environmental Protection Agency and the California state legislature has resulted in cleaner air. Here, progress to date and future intentions for emissions from gasoline and diesel vehicles are discussed.

There is no doubt about the success of precious metals in the clinic, with, for example, platinum compounds being widely used in the treatment of cancer, silver compounds being useful antimicrobial agents and gold compounds used routinely in the treatment of rheumatoid arthritis. The medicinal properties of the other platinum group metals are now being recognised and of these a ruthenium anticancer agent has recently entered the clinic, showing promising activity on otherwise resistant tumours. Like all metal drugs, the activity of the ruthenium compounds depends on both the oxidation state and the ligands. By manipulating these features ruthenium-centred antimalarial, antibiotic and immunosuppressive drugs have been made. In addition, ruthenium has unique properties which make it particularly useful in drug design. In this review we discuss ruthenium from a clinical stance and outline the medicinal uses of ruthenium-based compounds.

The platinum group metals are well suited for use at extremely high temperatures under mechanical loads and simultaneous corrosive attack. They have high melting points, excellent chemical stability and are highly resistant to oxidation. When using these materials in the design of components it is necessary to have data available on their elastic properties as a function of temperature. In this paper, investigations are presented into the temperature dependence of Young’s modulus, the modulus of rigidity and Poisson’s ratio for platinum, platinum alloys, rhodium and iridium. Measurements were carried out at the Friedrich Schiller University, Jena, using a resonance technique. Influences from both the microstructure and the alloying elements on the elastic properties and their temperature dependence were found.

Interest in the alloys of the titanium-nickel system is due to their attractive properties: the high strength of nickel-based alloys, the ability of intermediate phases based on Ti2Ni and TiNi to undergo amorphisation and hydrogen absorption, and the thermoelasticity of TiNi-based alloys. Ti-Ni alloys are resistant to oxidation and corrosion in most mild corrosive environments, and are used in chemical, medical and engineering applications. Here, we report on alloys in the Ti-TiNi-TiRu composition range of the Ti-Ni-Ru system, where ruthenium additions produce some interesting effects. Using phase diagrams and experimental results, the constituents of high temperature alloys and alloying processes are discussed.