Platinum Metals Review - Volume 13, Issue 3, 1969

A complete range of noble metal screen printing inks for thick film circuits has been developed that can be co-fired within the same time-temperature cycle with the object of simplifying and reducing the cost of circuit production. The resistor compositions have been described earlier; this article outlines the development of the conductor inks in the range.

A new ruthenium plating bath has been developed which gives bright, adherent and pore-free deposits at high cathode efficiencies. Electro-deposited ruthenium has considerable potential applications in the field of light duty electrical contacts where mechanical wear is a problem, particularly for sliding surfaces such as slip rings.

Long-term calibration changes of rhodium-platinum thermocouples operating close to their maximum service temperatures are attributable to rhodium migration from the positive to the negative limb. In the metalclad thermocouple described here the effects of this phenomenon are considerably reduced by balancing the rhodium content of the sheath and of the thermocouple wires.

The magnetic properties of the 50 atomic per cent cobalt-platinum alloy are quite exceptional and make it one of the most powerful permanent magnet materials available. In this article the author reviews the accepted mechanisms for high coercivities in an attempt to establish which is the more likely to apply to equiatomic cobalt-platinum in its hard magnetic condition. Some original studies are also presented, and some suggestions are put forward for the further development of this material.

One of the most important applications for organometallic compounds is likely to be their use as homogeneous catalysts in the industrial production of organic chemicals. The majority of these catalysts will undoubtedly be complexes of the platinum metals. This article focuses attention on the problems associated with the production and characterisation of catalytically active species formed in solutions of a number of rhodium and ruthenium complexes. Factors determining activity are described and a suggested formulation for an active species is presented.