The deposition and oxidation resistance of aluminide coatings on γ-TiAl

摘要

The isothermal and cyclic oxidation behaviour of an aluminide coating on nominally stoichiometric γ-TiM were studied at 1100 °C in air and oxygen for up to 168h. Coatings were deposited by the halide-activated, pack cementation method. The growth rate of the coating was diffusion controlled. The aluminide coating consisted of a thick, uniform outer layer of TiAl{sub}3 and a thin inner layer of TiAl{sub}2. The aluminide coating greatly improved both the isothermal and cyclic oxidation resistance of γ-TiAl, forming a fine-grained and adherent Al{sub}2O{sub}3 scale. Interdiffusion between the aluminide coating and the TiAl substrate was rapid, but did not adversely affect the protective nature of the Al{sub}2O{sub}3 scale.