电热爆炸喷涂和等离子喷涂联合法制备热障涂层的研究

Investigation on Thermal Barrier Coatings Prepared by Electric Thermal Explosion Spray and Plasma Spray

采用电热爆炸喷涂和等离子喷涂联合制备热障涂层,以电热爆炸喷涂法在DZ125合金表面制备NiCoCrAlY粘结层,以等离子喷涂技术制备陶瓷顶层。利用扫描电镜(SEM)和X射线衍射(XRD)仪对所制备的粘结层进行分析,结果表明:电热爆炸喷涂的粘结层与基体结合良好,喷涂态的粘结层的相主要由Ni3Al组成。采用联合法制备的热障涂层,在喷涂态的陶瓷层、粘结层、基体3者结合良好,界面清晰。在高温热循环过程中,粘结层/陶瓷层界面间生成了连续、致密的Al2O3膜,阻碍粘结层的氧化。粘结层/TGO界面产生平行于界面的裂纹,是导致热障涂层失效的主要原因。

Bond coating was prepared on superalloy DZ125 by electric thermal explosion spray and top coating was prepared by plasma spray. Scanning electron microscopy was used to test coating microstructure and X-ray diffraction was employed to evaluate the phases of coating before and after thermal cycling. The results show that adhesion strength is very strong between bond coating and substrate. On the as-sprayed coating surface the phase Ni3Al is found. The traditional two-layered structure thermal barrier coatings prepared by electric thermal explosion spray and plasma spray have good high temperature behavior. After thermal cycling, Al2O3 is formed between bond coating and top coating, which protect the bond coating at high temperature. Microcrack occurred at TGO layer and bond coating, which results in the failure of thermal barrier coatings.