Atomic mobilities of both Co and Si in all the solid phases of the Co–Si system were obtained by the assessment of experimentally determined diffusion coefficients from the present and published work by using a diffusion-controlled transformation simulation. The first-principles calculations were performed in order to clarify the contradictory impurity diffusion coefficients of Co in Si by determining the diffusion activation energy. The concept of so-called average thermodynamic factor was extended so as to model binary compounds with certain homogeneity ranges. Based upon the atomic mobilities obtained, the diffusion growths of the compounds over wide temperature ranges were predicted. Comprehensive comparisons showed that most of the experimental data resulting from diffusion phenomena were well reproduced by the parameters obtained. The approach was of general validity and could be used to establish mobility databases of alloys.

Atomic Mobilities, Diffusivities and Simulation of Diffusion Growth in the Co–Si System. L.Zhang, Y.Du, Y.Ouyang, H.Xu, X.G.Lu, Y.Liu, Y.Kong, J.Wang: Acta Materialia, 2008, 56[15], 3940-50