High temperature oxidation and thermal shock properties of thermal barrier coating by CoCrAlY surface modification

CoCrAlY coating was prepared by air plasma spray (APS) on Ni-based superalloy surface, nano-scale Al film was deposited on CoCrAlY surface by electron beam evaporation and then modified by high current pulsed electron beam, finally the ceramic coating was deposited on CoCrAlY surface by APS. The high temperature oxidation test and thermal shock test of the thermal barrier coating in air atmosphere were carried out. The results show that the thermally grown oxide (TGO) formed at the interface of modified CoCrAlY coating and top coating had high continuity and compactness after high temperature oxidation at 1 050℃, effectively hinder the further development of oxidation and avoid the formation of corner oxide, and then, the high temperature resistance properties of the thermal barrier coating were improved. The thermal shock test under 1 050℃ high temperature holding and water quenching at 10℃ were conducted, the rate of abscission of thermal barrier coating is only about 2%.