Load Characteristics Of Micro-arc Oxidation Process Of Magnesium Alloy Based On Voltage Output Waveform Analysis

In this paper,experiment using the monolithic pulsed power supply in the silicate system electrolyte solution at a frequency of 600 Hz,a duty cycle of 30%,a positive and negative pulse ratio of 1: 0.The equivalent impedance resistance and the capacitance Value of the microarc oxidation load at different stages is measured by an LCR tester.The variation law of the load electrical characteristics under different area and the influence of different electrical characteristics on the voltage waveform were studied.The load equivalent circuit at different stages was established and analyzed by Multisim software to verify the model Correctness.By measuring the load electrical characteristics,it is found that as the voltage increases,the equivalent impedance and resistance of the load increase,the capacitance decreases,the impedance resistance and the capacitance change faster before the arc voltage;With the larger area the equivalent impedance and resistance is smaller and capacitance is bigger under the same voltage.With the progress of micro-arc oxidation,the electrical characteristics of the load continue to change,this change changes the voltage waveform characteristics.It is found that when the voltage is lower than the arc voltage,the voltage waveform tends to the DC voltage at little area.When the voltage is higher than the starting voltage,the voltage waveform exhibits the discharge effect.With the increase of the load area,Before the arc voltage,the voltage waveform appears to a discharge effect.In this paper,we analyze the reasons of different waveforms at different stages and different areas,and think that the different representations are due to the different load electrical characteristics and the number of micro-arc discharge channels.Through the waveform analysis,two stages of the load circuit model are established,that is,before the arc is RC series circuit,after the arc is RC and then connected in series with a resistor R1 circuit equivalent model.The application of Multisim software simulation of the model pulse signal,Comparing actual waveform and model output waveform acquisition both are consistent.Therefor,the results show that the model can be applied to the analysis of micro-arc oxidation load,and provide a theoretical model for the further study on the micro-arc oxidation load characteristics in the future.