An electron microscope examination of small cobalt particles precipitated in a gold matrix

Abstract

Transmission electron microscope observations have been made on thin foils of a gold 1.5% cobalt alloy aged at 565°c after quenching from 880°c. The observations suggest that most of the ferromagnetic cobalt precipitate particles are in the form of discs in 〈100〉 planes which are arranged in sheets, also on 〈100〉 planes. The contribution to the coercivity of the alloy from these particles due to shape anisotropy is small and the high coeroivity of the alloy is probably due to some other type of anisotropy.