Growth kinetics analysis of Nb–Al intermetallic compounds interfacial layers based on Nb–Al phase diagram

Abstract A model for studying the growth kinetics of intermetallic compounds by means of binary phase diagrams was proposed with some assumptions. The parabolic growth relationship of intermetallic compound is deduced mathematically using analytical solution of diffusion equations and the mass balance law. By comparing the solubility of the adjacent phase in intermetallic compound phase, the predominant parameter controlling the growth kinetics is the solute diffusion coefficient. The diffusion coefficient of Al atoms in intermetallic layers is quantitatively described and the smallest diffusion coefficient is 0.373 × 10−21 m2/s in Nb3Al phase. It is demonstrated intermetallic layers formed at interface indeed inhibit the Nb container being corroded further by TiAl melt, and Nb3Al layer is a dominant factor.