Modeling of the interfacial interaction of nickel with silicon carbide under proton irradiation

Abstract

A quantitative model of the interfacial interaction of the silicide-forming metal Ni with single-crystal SiC has been developed for the first time. It is based on the interdiffusion of components, accounting for Kirkendall effect and the volume reactions of the formation of silicides of metal. The model enables a satisfactory description of the basic features of component redistribution in the system Ni–SiC under irradiation with protons at elevated temperatures, namely: existence of an extended reaction zone, excess of carbon concentration over that of silicon at the interface with a SiC substrate, and accumulation of carbon near the surface. It is shown that proton irradiation raises the diffusion coefficient of the metal by a factor of 2–4 and the rate of the chemical reactions by a factor of 10–20. Both these effects are attributed to the generation of elementary radiation defects, interstitial atoms and vacancies, which accelerate the diffusion and serve as a source of free volume.