【摘要】 在AZ91合金基体上制备了纯Al₂O₃涂层和Al₂O₃-13wt.%TiO₂（简称AT13）复合涂层,研究了两种涂层的显微形貌、涂层厚度、物相组成、显微硬度和结合强度,并分析了等离子喷涂的作用机理。结果表明,Al₂O₃涂层和AT13涂层中的陶瓷涂层、中间Ni/Al粘结层和AZ91合金基材之间实现了机械冶金结合;Al₂O₃涂层主要由亚稳态的γ-Al₂O₃和少量的稳态α-Al₂O₃组成;AT13涂层的主要物相为Al₂O₃、TiO₂和Al₂TiO₅;无论是Al₂O₃+Ni/Al喷涂涂层还是AT13+Ni/Al喷涂涂层,其工作涂层和粘结层的显微硬度都要明显高于汽车发动机用AZ91合金基材;Al₂O₃+Ni/Al涂层的结合强度为15.49 MPa,而AT13+Ni/Al涂层的结合强度为20.46 MPa,且前者的断口特征为粘结层破断,而后者的断口特征为涂层层间破断。更多还原

【Abstract】 Pure Al₂O₃ coating and Al₂O₃-13 wt.% TiO₂ composite coating were prepared on the base of AZ91 alloy, the microstructure, thickness, phase composition, microhardness and bonding strength of the coatings were studied, the mechanism of plasma spraying on the coating was analyzed. The results show that the mechanical and metallurgical bonding between the ceramic coating, the intermediate Ni/Al bonding layer of the Al₂O₃ and AT13 coatings and the AZ91 alloy substrate are realized. Al₂O₃ coating is mainly composed of γ-Al₂O₃ metastable state and a small amount of α-Al₂O₃,the main phases of AT13 coating are Al₂O₃, TiO₂ and Al₂TiO₅. The microhardness of the coating and the bonding layer of the coating are higher than that of the AZ91 alloy substrate, whether it is a Al₂O₃+Ni/Al coating or AT13+Ni/Al coating.Bonding strength of Al₂O₃+Ni/Al coating is 15.49 MPa, and the bonding strength of AT13+Ni/Al coating is 20.46 MPa, and the fracture characteristics of the former is the bond breaking, and the latter is the breaking of the coating layer.更多还原