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

Graphical abstract Highlights • Si-Al composite coating was prepared on γ-TiAl alloy by a two-step method. • SiO 2 coating was electrodeposited on pack aluminizing coating. • Porous SiO 2 coating turns to be compact after oxidation. • The Si- and Al-enriched oxide scale provides good oxidation resistance. Abstract 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. [ABSTRACT FROM AUTHOR]