Study Micro-arc Oxidation Combined With Conductive Composite Coating On Magnesium Alloy

Micro-arc oxidation technology can make magnesium surface obtain ceramic layer. If electroless plat on the surface, It not only has good corrosion resistance, but also achieve the conductive to expand its application scope.With micro-arc oxidation, through the study of ceramic layer growth process and phase change regularity. The results of SEM and X-ray diffraction analysis showed that the micro-arc oxidation film has many pores, osteoporosis layer, dense layer, the transition layers. mainly is for MgO,Mg,Mg₂SiO₄. Polarization curves and Tafel slope test results are in the thickness of 10μm, appear all sorts of factors, ceramic layer of corrosion resistance good than 5μm and 20μm.Research shows that: according to the process of micro-arc oxidation film, special structure using hydrochloric acid concentration of sensitivity, low activation distribution pretreatment with will reach the ideal effect. It get the electroless nickel plating technologyformula.SEM observation shows that different micro-arc oxidation film thickness on the surfaceof electroless nickel plating on different morphology, this basically is before the impact of microscopic structure matrix. Spectral line analysis shows that the electroless nickel plating layer with micro-arc oxidation film plays an interlock, the good. Heat treatment temperature reaches 400 degrees, can greatly improve the coating hardness. The accelerated corrosion test results showed that compound coating is better than a single membrane layer of corrosion resistance. Electroless nickel plating layer resistivity of coating thickness increases with the decrease in thickness, about 10μm, resistivity tend to be fixed value.