Modelling of alloying process of cold sprayed Ni/Al coating

Cold spray technology can reduce the oxidation of the as-sprayed coating and improve the reliability of thermal barrier coatings. Modelling the cold spray process can provide an approach to improve the process, and then increase the quality of the coatings. In this paper, a diffusion model with stress effect is introduced to analyze the alloying process of Ni/Al coating, and the effect of residual stress induced by cold spray is considered. The quantitative relationship between the thickness of ball milled Ni/Al splat and the alloying time is investigated. The presented model shows that tensile residual stress increases the concentration of Al in the Ni/Al coating, while compressive residual stress exhibits the opposite effects. The relationship between the thickness of ball milled Ni splat and the alloying time significantly deviates from the common parabolic law. And the reduced alloying time by ball milling Ni/Al powder is obtained quantitatively.