Influence of multilayer coatings on AZ31 deposited by electron beam evaporation
(1.上海市上海交通大学轻合金精密成型国家工程中心
2.National Engineering Research Center for Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China
3.National Engineering Research Center of Light Alloys Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China
4.Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai 200030, China)
2.National Engineering Research Center for Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China
3.National Engineering Research Center of Light Alloys Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China
4.Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai 200030, China)
Abstract: Three different coatings, Cr, SiO2/Cr and HfO2/SiO2 were deposited by electron beam physical vapor deposition (EB-PVD). Relevant composition and mechanical properties were obtained. The results show that the surface mechanical property could be increased, and Cr coating sample possessed the highest microhardness. Cyclic oxidation in air at 773 K was applied to evaluate the oxidation resistance of the coatings, and the section morphologies of the coatings were observed by FEISEM. The results indicate that the oxidation rate of AZ31 with Cr, SiO2/Cr and HfO2/SiO2 coatings is decreased, and the SiO2/Cr coating sample exhibits the best oxidation resistance and keeps relatively good adhesion up to 96 h. Polarization results prove that the corrosion resistance of AZ31 can be improved and the SiO2/Cr coating sample has the best property.
Key words: magnesium alloy; physical vapor evaporation; cyclic oxidation; corrosion resistance