Influence of multilayer coatings on AZ31 deposited by electron beam evaporation

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.

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 HtO2/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 ofAZ31 can be improved and the SiO2/Cr coating sample has the best property.