Formation of Mg₂Ni alloy layers and kinetic studies in the binary Mg-Ni system

We report here the study on the kinetics and growth of Mg₂Ni alloy layers by solid-state reactions in the Mg-Ni system. After appropriate heat treatments, only polycrystalline Mg₂Ni phase was found to form on the Mg/Ni interfaces and the grain sizes of Mg₂Ni formed near the Mg side were found to be much smaller than those formed near the Ni side. Cross-sectional SEM examinations revealed that the Mg₂Ni intermetallic layers grew following the diffusion-control process. During the formation of Mg₂Ni layers, the dominant diffusing species was determined to be Ni by using the immobile trench markers. Furthermore, based on the marker analysis, the intrinsic and interdiffusion diffusivities for the Mg-Ni diffusion couples at different temperatures have been determined.