Characterization of TiAlSi coating deposited by Arc-PVD method on TiAICrNb intermetallic base alloy

Results of microstructural investigations of aluminide coatings modified by Si are presented in this work. Protective coating (TiAlSi type) was deposited by Arc-PVD. Thickness of the outside layer of deposited coating was 35μm and it contained TiAb phase modified by Si as a main component. The second layer was found as a transition area between the TiAl₃ outside layer and the surface of TiAlCrNb substrate. Thickness of the inside sublayer was 5 μm. The diffusion treatment caused the progress of coating homogenisation from the point of view of phase and chemical composition. It was found that the coating consisted of the dominant TiAl₃ phase and Ti₅Si ₃ in thick outer sublayer and only TiAl₂ phase in transition thin sublayer. Below the transition area, on the surface of TiAlCrNb substrate alloy, the layer of γ-TiAl was found. The amount of suicides was increased in comparison with the coating only after the Arc-PVD process and the area of its presence had been removed in the outside direction of the coating.