WANG Jianping ¹, SHI Yunxia ¹, WU Shaobo ¹, WEI Jindong ², TANG Xiangqing ¹
(1. Jiangsu College of Engineering and Technology, Nantong 226007, Jiangsu, China; 2. School of Mechanical Engineering,
Nantong University, Nantong 226019, Jiangsu, China)

Abstract: Al₂O₃-Cr₂O₃ composite coatings were prepared on 45 steel substrate by atmosphere plasma spraying. The microstructure and phase of the coating were analyzed by SEM and XRD, the bonding strength, porosity, hardness and wear rate were tested by universal testing machine, hardness tester and wear test machine. The results showed that γ-Al₂O₃ phase gradually decreased and α-Al₂O₃ phase increased with the increase of Cr₂O₃, the composite coatings possessed better comprehensive mechanical properties and density than Al₂O₃ coating. The coating performance was the best at 40% Cr₂O₃ content: the porosity was 1.1%, the tensile bond strength was 12 MPa, the shear bond strength was 23.45 MPa, the hardness was 1010 HV, and the wear rate was 0.34%.

Key words: plasma spraying; Al₂O₃-Cr₂O₃ composite coating; microstructure; phase; mechanical properties