In order to improve the high temperature oxidation resistance of TiAl alloys,the rare earth Ce modified NiCrAlY coatings were prepared on TiAl alloys by atmospheric plasma spraying.The oxidation tests of NiCrAlY and NiCrAlYCe coatings were carried out at 900 ℃ for 100 h.The effect of rare earth Ce on the microstructures and phase compositions of NiCrAlY coatings were analyzed,and its effect on the high temperature oxidation mechanism was further discussed.The results indicated that the addition of rare earth Ce can improve the high temperature oxidation resistance of NiCrAlY coatings effectively.After oxidation at 900 ℃ for 100 h,the addition of rare earth Ce reduced the oxidation weight gain of NiCrAlY coating by 16％and decreased the oxidation rate by 33％.The rare earth Ce can promote the selective oxidation of Al and inhibit the production of NiCr2O4 spinel oxides,thus inhibiting the internal diffusion of O.The addition of rare earth element Ce reduced the thickness of the interdiffusion zones of the NiCrAlY/TiAl systems.The slow growth of the oxide layers and the element interdiffusion rate are beneficial to improve the bonding and oxidation resistance of the NiCrAlY coating.
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