INTERDIFFUSION IN IRON-COBALT ALLOYS.

Abstract

Interdiffusion coefficients in bcc and fcc alloys of the iron-cobalt system were determined as a function of composition and temperature by use of an electron probe x-ray microanalyzer. Kirkendall effects were studied using alumina powder markers. The concentration dependence of the interdiffusion coefficients is at a minimum at 25 at. % Co in the bcc alloys and at a maximum of 60 at. % Co in the fcc alloys. Intrinsic diffusion coefficients calculated at marker compositions were found to be larger for Fe than for Co in agreement with the formation of voids on the Fe-rich side of the diffusion couple.