Oxidation protection of NiCoCrAlY coatings on gamma-TiAl

The effect of NiCoCrAlY overlay coatings on the oxidation resistance of g-TiAl was studied at 900 D C in static air. To hinder the interdiffusion of the elements, the Al/Al2O3 layer was added between the coating and the alloy. The results show that the TiAl alloy exhibits poor oxidation resistance. NiCoCrAlY coating can not effectively protect the g-TiAl substrate from high temperature oxidation because of the serious interdiffusion between the coating and the substrates. With Al/Al2O3 diffusion barrier, the NiCoCrAlY coating exhibits excellent oxidation protection on g-TiAl alloy.