GH220/Ti──N/CoCrAlTaY/Al三层复合涂层的界面稳定性及其自分层行为研究

 GH220/Ti-N/CoCrAlTaY/Al三层复合防护涂层经扩散退火后，各层间结合较好，Ti-N组织稳定，Al全部扩散进入CoCrAlTaY内部，形成β-CoAl相。1000℃时效试验发现，Al内扩散导致CoCrAlTaY分层，形成7个亚层（不包括氧化膜及Ti-N膜）,其中包括3个富Ta层、2个高Al及2个正常CoCrAlTaY层。各亚层间界面随时效时间延长而趋于平直、连续、完整。在一些亚层内侧观察到Kirkendal空穴，其形成与元素的外扩散有关。分析了GH220/Ti-N界面扩散区的形成原因，建立了富Ta层形成模型。

INTERFACIAL STABILITY AND SELF SCALING BEHAVIOR OF A NEW MULTI LAYER GH220/Ti N CoCrAlTaY/Al PROTECTIVE COATING

Experimental results show that, after being diffusion annealed, each layer in the Ti N/CoCrAlTaY/Al multi layer composite coating is firmly bonded with the neighboring ones, the microstructure of Ti N film is stable, and that Al has completely diffused into the CoCrAlTaY, giving rise to the formation β CoAl compound. It was discovered that after being aged at 1000℃, the CoCrAlTaY layer will self divided into 7 sub layers (not including the outer oxide film and Ti N layer), 3 of which are enriched with Ta, 2 of which contain more Al, and 2 of which are normal CoCrAlTaY sub layers. With the prolonging of aging time, the boundaries between different sub layers tend to be more straight, continuous, and integral. Kirkendall vacancies were observed on the inner side of some sub layer, indicating the diffusion of atoms towards the outer side. The formation mechanism of Ta enriched sub layer and the diffusion zone between GH220/Ti N have been interpreted.