(1. 天津大学 材料科学与工程学院，天津 300072；
2. 天津大学 天津市现代连接技术重点实验室，天津 300072)
摘 要: 为了缓解涂层和基体之间的热失配应力，采用化学镀方法在2A70铝合金表面上制备Ni-P和Ni-Cu-P过渡层；然后在镀层表面依次制备CoNiCrAlY粘结层和ZrO2-8%Y2O3(8YSZ)陶瓷层(质量分数)，获得复合热障涂层；并采用热循环方法评定该涂层体系的抗热震性能。结果表明，采用Ni-P镀层和Ni-Cu-P镀层作为过渡层的试样的热震寿命分别约为1000次和500次；Ni和Al元素的互扩散使过渡层与基体界面区域形成了扩散层和岛状颗粒，一些颗粒与扩散层连通后提高了涂层与基体的结合强度，但孤立的颗粒由于变形能力差，对涂层的寿命有不利影响；在交变应力下颗粒与基体界面处会形成裂纹，并最终导致涂层剥离。
关键字: 热障涂层；大气等离子喷涂；化学镀；失效机制
（1. School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China;
2. Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300072, China）
Abstract:To relieve the thermal mismatch stress between coatings and substrate, Ni-P and Ni-Cu-P electroless platings were fabricated onto 2A70 aluminum as interlayers. Subsequently, the specimen with plating was covered by CoNiCrAlY bond coat and ZrO2-8%Y2O3(8YSZ) top coat (mass fraction), then a novel thermal barrier coating (TBC) was produced. The thermal shock resistance of TBCs was evaluated by heat cycle test. The results indicate that the lifetimes of TBC with Ni-P interlayer and Ni-Cu-P interlayer are about 1000 cycles and 500 cycles, respectively. The interdiffusion of Ni and Al results in the formation of diffusion layers and island particles at the interface between interlayers and substrate. The connection between particles and diffusion layers improves the adhesion of coatings with substrate, while isolate particles are harmful to the lifetime of coatings due to their poor deformation ability under alternative stress. Crack initiation happens at the interfaces between particles and substrate, which leads to coatings spallation.
Key words: thermal barrier coating; air plasma spray; electroless plating; failure mechanism
