The diffusion-controlled growth of Fe2Al5 was studied in bulk Fe–Al solid-state diffusion couples annealed for 600s to 1.5h at 773 to 873K. The layer growth kinetics were parabolic. The parabolic growth constants of the second kind for the exclusive growth of Fe2Al5 from the adjacent phases were calculated from the measurement on the Fe–Al diffusion couples. The rate constants of the second kind were in turn related to the diffusion properties of the aluminide. As a result, the interdiffusion coefficient, taking into account the diffusion of both elements, was obtained for Fe2Al5 phase. The resulting activation energy was 84.9kJ/mol.

Reactive Diffusion in the Roll Bonded Iron–Aluminum System. V.Jindal, V.C.Srivastava, A.Das, R.N.Ghosh: Materials Letters, 2006, 60[13-14], 1758-61