Corrosion Resistance of Magnetron Sputtered Titanium + Micro Arc Oxidizing Composite Coating on 7075 Aluminum Alloy

In view of the poor corrosion resistance of 7075 aluminum alloy in marine environment， the microstructure and corrosion resistance of composite oxide coating on the surface of 7075 aluminum alloy obtained by combining magnetron sputtering and micro arc oxidation technologies were investigated. Firstly， the aluminum alloy surface was pre-coated with titanium film by magnetron sputtering technology， and then a composite oxide coating was prepared by micro-arc oxidation technology. The microstructure and phase composition of the composite oxide coating were analyzed by SEM， EDS and XRD. The corrosion resistance of such coating in 3.5% NaCl solution was studied by electrochemical workstation. Results showed that compared with the oxide coating obtained by a direct micro arc oxidation of aluminum alloy， the composite oxide coating formed on the Ti-coated aluminum alloy by micro arc oxidation had lower porosity and higher thickness， presenting better corrosion resistant performance.