Under The Conditions Of Different Electrical Parameters Of Aluminum, Magnesium Alloy Micro-arc Oxidation Ceramic

Micro-arc oxidization surface processing occurs together with complicated physical, chemical and electrochemical reactions. Those reactions are influenced by electrolyte solution, electricity parameter, processing temperature, etc, among which the electricity parameter is one of the primary factors. Aluminum alloy and Magnesium alloy micro-arc oxidization ceramic layer are made under the different conditions of electricity parameter by employing the self-designed MAO series equipments. According to the compare and analysis of the experiment results, the influences of electricity parameter such as current density, frequency, duty ratio, and numbers of positive and negative pulse on ceramic layer have been studied in this article. The mainly research results are:1) The thickness of the Aluminum alloy ceramic layer increases with adding cvirrent density while it decreases with adding negative pulse. The roughness of the ceramic layer is low when adding the negative pulse. The countercheck effect of the ceramic layer is strong enough to reduce the rate of corrosion and increase its corrosion resistance when the number of negative pulse is 2 and 4.2) Aluminum alloy ceramic layer is mainly made up of the three phases of (X-AI2O3, Y-AI2O3 and 8-AI2O3. The phase of (X-AI2O3 has tight structure and high hardness and is the main phase for increasing the hardness of ceramic layer.3) The roughness of Magnesium alloy ceramic layer is low when the frequency is high. Under the condition of high frequency, the roughness of the ceramic layer is higher whether the duty ratio is bigger.4) The corrosion resistance of the Magnesium alloy micro-arc oxidization ceramic layer is higher than that of the anodic oxidation layer. The corrosion current of the Magnesium alloy micro-arc oxidization ceramic layer in 3.5%NaCl solution is lower with three orders of magnitude than that of the anodic oxidation layer.