High temperature oxidation resistance of γ-TiAl alloy with pack aluminizing and electrodeposited SiO2 composite coating

A novel Si-Al composite coating was prepared on γ-TiAl alloy by a two-step method. Firstly, an aluminizing coating was fabricated on γ-TiAl alloy via pack cementation technique. Then a SiO 2 coating was prepared on this aluminizing coating via cathodic electrodeposition. The high temperature oxidation resistance of this composite coating was evaluated under 1000 °C. During the oxidation process, this Si-Al composite coating can react with TiAl and prevent the inward diffusion of oxygen from air to the film/alloy interface, resulting in the remarkable decreased oxidation rate of the alloy.