Study on high-temperature oxidation and thermal shock properties of a Ni/Al coating on TiAl alloy

The problem of insufficient oxidation resistance of a TiAl alloy above 800 °C has limited its broader application. In this paper, Ni/Al composite coatings were deposited on TiAl alloy. The high-temperature oxidation resistance and thermal shock behavior of the Ni/Al coatings were systematically investigated. The composition of the oxidized coating from the surface to the interior consisted of an Al 2 O 3 oxide film, a NiAl compound layer, a Ni layer, a TiAl 3 diffusion layer, and a Ti 2 Al diffusion layer. The Al 2 O 3 oxide film and NiAl compound layer effectively hindered the inward diffusion of oxygen and the outward diffusion of titanium. The local failure of the coating in thermal shock experiments began with the initiation and propagation of pores and cracks.