Carbon in Platinum and Palladium

Carbon diffuses rapidly through heated membranes of platinum and palladium even though its solubility in the former metal is less than 0.02 per cent by weight at 1700°C. Palladium takes up more than 0.4 per cent by weight of carbon at 1400°C and this interstitial solubility hardens it considerably and distends the lattice. The effects of carbon on the microstructure and mechanical properties of platinum and palladium are described in this article, which dispels some illusions and surveys the practical consequences of the constitutional relationships observed.