Platinum Metals Review - Volume 48, Issue 2, 2004

Platinum-based composites are potential materials to substitute for platinum in some applications, for example, for containers in which to grow single crystal oxides. Ceramic coated platinum is the best material for crucibles as: first, the cylindrical geometry is suitable for coating with ceramic; second, the ceramic coating carries the basic mechanical loading, with the platinum acting both as the heater and anticorrosive coating; and third, refining this secondary platinum for recycling is neither a complicated nor expensive procedure. Plasma evaporation of alumina onto platinum is a technology that can be successfully applied to manufacturing commercial composite containers. In this paper the problem of cohesive strength between Pt and Al2O3, and the morphology and properties of the transition layer between the metallic matrix and the ceramic will be discussed.

Since 1996, Tanaka Kikinzoku Kogyo K.K. has been producing flocculate platinum fibre and non-woven fabric made from this fibre. The background to the production of this material is briefly described. Flocculate platinum fibre and fabric are currently used as filtering materials in filtering applications that require both heat and chemical resistance. The platinum fibre and fabric are also finding application as electrically conductive fillers for porcelain enamel.

Nineteenth century Russian roubles are collectors items, but because of their history, there is a question over each one whether it is a genuine Russian rouble or a forgery. There has been some prior research and analysis on the platinum used to make these roubles and on their method of manufacture. As W. C. Heraeus and Johnson Matthey both hold small collections of roubles never before investigated, it was decided to see what could be found out about them and what this could tell us about their origins. This is the first of a three part series and begins with some of the background history to the work. Part II appears later in this issue and Part III will be published in July.

Heraeus has in its possession four platinum rouble coins and one commemorative platinum medallion minted between 1826 and 1844. In order to determine their composition and to learn a little more about the methods used in their manufacture, they have been subjected to various techniques of non-destructive examination. These have included a developmental SQUID microscope specifically used to look at magnetic effects due to the iron content.