GROWTH OF SILICIDES IN NI-SI AND NI-SIC BULK DIFFUSION COUPLES

In this work, the integrated diffusion coefficient, D-int, is used to describe the growth kinetics of silicides in Ni-Si and Ni-SiC diffusio n couples. The integrated diffusion coefficients are determined from p lanar diffusion couple experiments for all intermetallic phases of the binary Ni-Si system between 1073 and 1173 K. For the growth of Ni5Si2 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 dif fusing species in Ni3Si and Ni5Si2. In NiSi2, Ni and Si are equally mo bile. 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.