Growth of Silicides in Ni-Si and Ni-SiC Bulk Diffusion Couples

Abstract

In this work, the integrated diffusion coefficient, D int , is used to describe the growth kinetics of silicides in Ni-Si and Ni-SiC diffusion couples. The integrated diffusion coefficients are determined from planar diffusion couple experiments for all intermetallic phases of the binary Ni-Si system between 1073 and 1173 K. For the growth of Ni 5 Si 2 an activation energy of 180 ± 30 kJ/mol (1.9 ± 0.3 eV) was found. The position of the Kirkendall plane revealed that Ni is the only diffusing species in Ni 3 Si and Ni 5 Si 2 . In NiSi 2 , Ni and Si are equally mobile. The activation energy for the interdiffusion in the Ni(Si) solid solution, measured between 1093 and 1423 K, is 250 ± 10 kJ/mol (2.6 ± 0.1 eV) and is independent of the Si-concentration.