Interdiffusion in the Ni–Mo system

The interdiffusion coefficient in Ni(Mo) solid solution, impurity diffusion of Mo in Ni, average interdiffusion coefficient of the NiMo–σ phase and activation energies for diffusion in solid solution and in the σ phase of the Ni–Mo binary system are evaluated through the diffusion couple approach. These results are utilized to identify the possible diffusion mechanism. Low activation energy in the σ phase indicates a grain-boundary-controlled diffusion process.