Solid-state interdiffusion in Ni-Mo diffusion couples at high temperatures

It has been demonstrated that self-propagating explosive reactions could occur in a binary Ni/Mo system at elevated temperatures, based on a thin-film diffusion couple geometry. According to the study, measurable solid-state interdiffusion took place after vacuum annealing at 700 C for 6 h. The reaction, in turn, resulted in the formation of a single-phase reaction product δ-NiMo in a two-layered reaction zone. With an attempt to further understand the underlying mechanism for the formation of δ-NiMo, the authors investigate in this paper solid-state interdiffusion in Ni-Mo bulk diffusion couples. To the best of their knowledge, interdiffusion in the Ni-Mo system has not been adequately studied. Very limited information is available with regard to the evolution of diffusion pattern and its reaction products. A better understanding of solid-state interdiffusion in Ni-Mo is also beneficial to the thermal-mechanical-processing of corrosion-resistant Hastelloy alloy B2