Interdiffusion Between Ti 3 SiC 2 –Ti 3 GeC 2 and Ti 2 AlC–Nb 2 AlC Diffusion Couples

In this work, we report on the interdiffusion of Ge and Si in Ti 3 SiC 2 and Ti 3 GeC 2 , as well as that of Nb and Ti in Ti 2 AlC and Nb 2 AlC. The interdiffusion coefficient, D int , measured by analyzing the diffusion profiles of Si and Ge obtained when Ti 3 SiC 2 –Ti 3 GeC 2 diffusion couples are annealed in the 1473–1773 K temperature range at the Matano interface composition (≈Ti 3 Ge 0.5 Si 0.5 C 2 ), was found to be given by image D int increased with increasing Ge composition. At the highest temperatures, diffusion was halted after a short time, apparently by the formation of a diffusion barrier of TiC. Similarly, the interdiffusion of Ti and Nb in Ti 2 AlC–Nb 2 AlC couples was measured in the 1723–1873 K temperature range. The D int for the Matano interface composition, viz. ≈(Ti 0.5 ,Nb 0.5 ) 2 AlC, was found to be given by image At 1773 K, the diffusivity of the transition metal atoms was ≈7 times smaller than those of the Si and Ge atoms, suggesting that the former are better bound in the structure than the latter.