Platinum Metals Review - Volume 11, Issue 4, 1967

The rapid development of thick film integrated circuits has created a need for preparations that will provide resistor films on a variety of substrates. In the development of the new range of materials described in this article advantage has been taken of the complex mechanism of conduction through ruthenium dioxide.

The merits of the platinum metals as electrocatalysts in a large number of fuel cell systems featured in a high proportion of the papers presented at the Second International Conference on the Study of Fuel Cells, organised by the Société d’Etudes de Recherches et d’Applications pour l’Industrie (SERAI) and the Société Commerciale d’Applications Scientifiques (COMASCI) and held recently at the University of Brussels.

Although platinum-clad molybdenum is used extensively as a material for handling molten glass, surprisingly little is known about the constitutional relationships in this refractory metal binary system. Recent work in the Johnson Matthey Research Laboratories has confirmed that the published equilibrium diagram is incomplete and that four intermediate phases are formed at high temperatures. This work has provided a better understanding of the behaviour of platinum-clad molybdenum equipment under operating conditions in the glass industry.

The platinum metals react with some of their closer neighbours in the Periodic Table to produce intermediate phases of high stability. While this behaviour tends to confirm some of the predictions made by protagonists of the Engel-Brewer theory of alloying, the general validity of this theory is still a matter of vigorous controversy. In this article some of the conflicting opinions that have been advanced are reviewed and discussed.

Modern techniques are steadily increasing our knowledge of the structure and properties of the supported platinum metal catalysts so widely used in chemical processing. The main function of the support, such as charcoal, alumina or silica, is to increase the surface area of the platinum metal and so to enhance catalyst performance, and methods for studying the dispersion of the platinum are therefore of considerable importance. This article describes the application of electron microscopy to the problem and compares the results given by this and other methods.