Reactive Diffusion in Ni-Si Bulk Diffusion Couples

Abstract Reactive diffusion in the Ni-Si system has been studied using bulk polycrystalline Ni/Si wafer diffusion couples in the temperature range from 450 to 700 °C and with annealing times of up to 32 h. For all diffusion couples, three phases were detected $ Ni_{2} $Si, $ Ni_{3} %$ Si_{2} $, and...
Ausführliche Beschreibung

Abstract Reactive diffusion in the Ni-Si system has been studied using bulk polycrystalline Ni/Si wafer diffusion couples in the temperature range from 450 to 700 °C and with annealing times of up to 32 h. For all diffusion couples, three phases were detected $ Ni_{2} $Si, $ Ni_{3} %$ Si_{2} $, and NiSi. The thickness e of the reaction product is not homogeneous; its global growth kinetics satisfies the parabolic law and the total growth coefficient k2 (e2 = k2t) is found to be expressed by: k2 = 2.5 × $ 10^{−4} $ exp (−160 kJ/RT), in $ m^{2} $/s. The $ Ni_{2} $Si layer is homogeneous in thickness, and the value of its growth coefficient obtained by extrapolation at lower temperatures is more than two orders of magnitude smaller than the values obtained in thin-film experiments. Ausführliche Beschreibung