Behavior of NiCrAIY coating on the TC6 titanium alloy

Abstract A NiCrAIY coating was deposited on the TC6 titanium substrate by arc ion plating (AIP). The structure and morphologies of the NiCrAIY coating were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the influence of vacuum heat treatment on the element diffusion behavior was studied. The results showed that the γ'-Ni 3 Al phase was precipitated on the NiCrAIY coating after heat treatment. The Ni 3 (Al,Ti), TiNi, and Ti 2 Ni intermetallic layers appeared at the interface from the outside to the inside at 700°C, and the thickness of the intermetallic layers increased with the increase in temperature. At 700°C Ti and Ni were the major diffusion elements, and the diffusion of Cr was observed when the heat treatment temperature increased up to 870°C. The violent inward diffusion of Ni at 950°C resulted in the degradation of the NiCrAIY coating.