Microstructure and high temperature oxidation behavior of the Al2O3 CPED coating on TiAl alloy

Abstract Al2O3 coating was fabricated on the surface of γ-TiAl alloy via cathodic plasma electrolytic deposition (CPED) technique. The microstructure and the composition of the coating were elaborately characterized. The results revealed that, the uniform coating combined well with the substrate, which was mainly composed of α-Al2O3, γ-Al2O3 and trace amount of amorphous Al(OH)3. Moreover, the high temperature oxidation behaviors of the substrate, the coating and their interface were investigated in detail. It was found that the existence of the Al2O3 coating could substantially decline the oxidation rate of TiAl alloy, because of the significant increase in high temperature oxidation resistance.