The integrated diffusion coefficient was used to describe the growth kinetics of silicides in Ni/Si and Ni/SiC diffusion couples. The coefficient was determined, from planar diffusion couple experiments, for all of the intermetallic phases of the binary Ni/Si system at temperatures of between 1073 and 1173K. An activation energy of 180kJ/mol (1.9eV) was found for the growth of Ni5Si2 (table 13). The position of the Kirkendall plane revealed that Ni was the only species which diffused in Ni3Si and Ni5Si2. In the case of NiSi2, the Ni and Si were equally mobile. The activation energy for interdiffusion in the Ni(Si) solid solution, at temperatures of between 1093 and 1423K, was 250kJ/mol (2.6eV). It was independent of the Si concentration.

J.H.Gülpen, A.A.Kodentsov, F.J.J.Van Loo: Zeitschrift für Metallkunde, 1995, 86[8], 530-9

Table 13

Diffusivity in Various Nickel Silicides