Effect of heat diffusion on properties of zinc-aluminum coating on AZ91D magnesium alloys
(1.School of Materials Science and Engineering, Chongqing Institute of Technology, Chongqing 400050, China
2.重庆市重庆科技学院材料科学与工程学院
3.School of Material Science and Engineering, Chongqing Institute of Technology, Chongqing 400050, China)
2.重庆市重庆科技学院材料科学与工程学院
3.School of Material Science and Engineering, Chongqing Institute of Technology, Chongqing 400050, China)
Abstract: A protecting zinc and aluminum coating on the surface of AZ91D magnesium alloys was obtained by thermal spraying to improve the corrosion and wear resistance performances. In order to enhance the combination between magnesium alloy matrix and zinc and aluminum coating, the sample was heat-treated at 300 ℃ for 2 h, then, the cross-section patterns, XRD pattern, micro-hardness, wear and corrosion resistance abilities were researched. The results indicate that the interface between the coating and substrate is metallurgical bond, and a transitional fusion layer is formed by diffusion. The micro-scale abrasion test and polarization test in 3% NaCl solution show that the diffusion-treated specimen has better wear and corrosion resistance performances in comparison with the undiffusion-treated and substrate magnesium alloys; in addition, it has relatively higher micro-hardness than the undiffusion-treated magnesium alloys.
Key words: magnesium alloy; zinc-aluminum coating; heat diffusion; wear; corrosion