CoCrAlY表面改性后热障涂层高温氧化及热震性能

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

关键词:  强流脉冲电子束  微观形貌  高温氧化  热震

Key words:  high current pulsed electron beam  microstucture  high temperature oxidation  thermal shock

摘要:

采用大气等离子喷涂技术（APS）在镍基高温合金表面制备了CoCrAlY粘结层，利用电子束蒸发镀膜在CoCrAlY表面蒸镀纳米铝膜，并使用强流脉冲电子束熔敷纳米铝膜进行表面改性，最后使用APS在表面改性后的CoCrAlY表面沉积陶瓷层制备了热障涂层.在空气环境中对热障涂层进行高温氧化试验和热震试验.结果表明，CoCrAlY表面改性后热障涂层经1 050℃静态空气氧化后，界面处生成的热生长氧化物（TGO）具有较高的连续性和致密性，有效阻碍了氧化的进一步发展且避免尖角型氧化物的形成，提高了热障涂层的抗氧化能力；在1 050℃高温加热后10℃水淬热震条件下，脱落率仅为2%左右.

Abstract:

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%.