铜基体上制备ZrO_2-NiCrAlY梯度喷涂层的组织及其性能

Microstructure and Properties of Plasma Sprayed ZrO_2-NiCrAlY Gradient Coatings on Copper Substrate

功能梯度涂层能提高涂层与基体间的结合力、耐磨性,以往对铜基体上喷涂功能梯度涂层的研究较少。用等离子喷涂法,在铜基体上制备了ZrO2-NiCrAlY梯度涂层。利用扫描电镜对涂层的组织形貌、成分进行了分析,对涂层的结合强度和抗热震性能进行了试验研究,并对试样进行了高温扩散处理。结果表明,梯度涂层设计合理,实现了成分和组织的连续梯度变化;与双层涂层相比,梯度涂层的结合强度和抗热震性有显著提高,涂层的结合以机械结合为主,梯度涂层内部是基体-涂层体系中最薄弱的环节;600℃热处理后,基体与涂层之间出现了扩散层。

ZrO2-NiCrAlY gradient coatings were prepared on copper substrate by using plasma spraying tech-nique. The microstructure and composition of the coatings were analyzed by means of scanning electron microscopy. The gradient coatings were diffused at elevated temperature, and their bonding strength and thermal shock resistance were evaluated. Results show that the properly designed gradient ZrO2 - NiCrAlY coatings have continuously changed gradient composition and microstruc-ture, and show much higher bonding strength and thermal shock resistance than dual - layer coatings. The gradient coatings were mainly bonded with the substrate by mechanical bonding, and the internal zone of the gradient coatings was the weakest of the sub-strate-coating system. Moreover, a diffusion layer was formed be-tween the coating and substrate after heat treatment at 600 ℃.