Phase equilibria in cobalt-rich portions of the Co-Si and Co-Ge systems

Abstract

The cobalt-rich portions of the Co-Si and Co-Ge systems between 700 and 1100°C have been investigated by means of electron probe microanalysis. The equilibrium between α(f.c.c.) and ε(c.p.h.) phases has been detected mainly by the diffusion couple technique, and it has been clarified that the c.p.h. phase is stable up to temperatures greater than 1100 °C in both the systems. It has also been found that the Co 3Ge phase, probably having an A15-type structure, exists somewhere between about 770 and 636 °C, being in equilibrium with the ε and βCo 5Ge 3 phases.