Research Of Low Energy Consumption Micro-arc Oxidation Technology On Aluminum Alloy

This paper is a series of experiment of Micro-arc Oxidation about how to achieve low energy consumption, selecting Na₂SiO₃ and KOH as the basic electrolyte. It is powered by direct current of pulse square wave. First, the proportion of the additive is optimized through orthogonal test, and the electricity parameter is advanced on energy saving. Then, current waveform is measured and saved through NI(virtual instrument) technique; the film's growing as well as the capacitance effects of electrolyte from the perspective of the waveform delay, and unit energy consumption and film growing velocity in the experiment are also researched. Finally, surface properties of the Micro-arc Oxidation ceramics film are analyzed.The concentration of basic electrolyte is Na₂SiO₃(5 g/L),KOH(1-2 g/L).A comprehensive analysis of such factors as film properties and unit energy consumption is conducted to achieve an optimal additive concentration: Tartaric sodium(2 g/L), Na₂WO₄(4 g/L),EDTA(2 g/L), Citric sodium(3 g/L).The electrolyte's electrical parameter, frequency 400Hz and dutyfactor 1/20, is the best combination under that concentration. Current density is always controlled at about 2A/dm² during the experiment process.The waveform delay of the power shows that there are capacitance effects in the whole loop, but it isn't a real capacitance which is described as double layers capacitance whose electrolyte is ceramic film and released gas. Due to its existence, the waveform of power supply is delayed which can improve the properties of ceramic film to certain extent. Meanwhile, it increases unit energy consumption and retards film growing velocity in the experiment.After analyzing the factors that influence unit energy consumption, we can conclude: 50 minutes for oxidizing is favorable in view of reducing unit energy consumption; the temperature under 50℃is proper for low unit energy consumption, at 3.8 kW·h/m²Î¼m, in the experiments. After analyzing the factors that affect film growing velocity, we can come to a conclusion that 50 minutes for oxidizing is a suitable temperature not only for rapid film growing speed but also for obtaining preferable film properties, and when the temperature is around 50℃, the film growing speed can reach 0.88um/min, the highest speed.All above are concluded under the condition of low concentration electrolyte and direct current power of pulse square wave which is used as experiment power. The goal of low energy consumption Micro-arc Oxidation is almost achieved,and industrialization of this technology can be realized.