The oxidation resistance was investigated in air at 1173K for the TiAl alloy, which has been pre-sulfidized at 1173K in a H
2-H
2S gas mixture to form a TiAl
3 layer on the alloy surface due to selective sulfidation of Ti, and changes of the TiAl
3 into TiAl
2 phase as well as their effects on oxidation behavior were considered.
It was found that the pre-formed TiAl
3 layer with 20μm thickness was changed into a TiAl
2 layer after oxidation at 1173K for 86.4ks. Both the TiAl
3 and TiAl
2 layers indicated very good oxidation resistance for long time, up to 810ks. These two layers showed re-passivation capability of forming a protective Al
2O
3 scale.
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