Growth kinetics of Mo3Si layer in the Mo5Si3/Mo diffusion couple

The diffusion processes and growth kinetics of the Mo3Si silicide layer occurring at annealing the Mo5Si3/Mo diffusion couple between 1180 and 1800 °C were studied by electrothermography. The experimental results are supplemented with calculations on the behaviour of the initial Mo5Si3/Mo diffusion couple on the basis of the reaction diffusion model describing the transformation of the Mo5Si3 layer into a Mo3Si one. The values of the parabolic growth constant for Mo3Si layer were determined and the silicon diffusion coefficient in the Mo3Si phase was calculated: D = 0.165 exp[(− 247 ± 10) / RT], cm2/s, where the activation energy is expressed in terms of kJ/mol.