Research On Key Technology Of Ultrasonic Micro Are Oxidation Of WE54 Magnesium Alloy

WE54 magnesium alloy is one of the Mg-Y-Nd system,become the most successful commercial magnesium alloys developed to date,because of WE54 magnesium alloy with high specific strength,good heat resistance,low density,and excellent high temperature creep resistance.In all walks of life,it has been applied to many fields,but because of weak corrosion resistance,and seriously restricts its application.In order to strengthen the corrosion resistance of WE54 magnesium alloy,it is a reasonable and effective way to make surface machining without changing the main properties of the substrate material.Micro-arc oxidation is a kind of special processing method which is environmentally friendly,easy to operate and has good machining effect.It is widely used in various metal surface processing.Ultrasound is also a widely used technology,especially in the preparation of medical materials and industrial cleaning equipment has been well applied,ultrasonic cavitation effect is applied in many areas of scientific research.In this paper,WE54 magnesium alloy was used as the research object,and used the method of ultrasonic and micro-arc oxidation to prepare ceramic coating on the surface of WE54 magnesium alloy.Before the experiment,the original micro-arc oxidation equipment was modified to form an effective integrated ultrasonic generator and its transducer with the micro-arc oxidation electrolyte tank.The micro-arc oxidation electrolyte composition of WE54magnesium alloy was explored through conventional micro-arc oxidation processing to determine the content of different components in the electrolyte and determine the final electrolyte formulation.Using orthogonal experimental method to analyze the effects of various process parameters on formation of coatings.Using the method of BP neural network,establish a prediction model between coating thickness and ultrasonic micro-arc oxidation process parameters.By electrochemical experiment compared the ordinary micro-arc oxidation and ultrasonic membrane coating thickness of micro-arc oxidation and corrosion resistance.The main research contents and corresponding conclusions are as follows:?1?Through the observation method,micro-hardness test,surface roughness test and other test methods,got the composition of the electrolyte with better micro-arc oxidation reaction,and found when the electrolyte was composed of sodium silicate,sodium hydroxide,sodium hexametaphosphate,sodium fluoride and glycerin,the micro-arc oxidation reaction process is smooth,and the micro-hardness and surface roughness of the coating are best,and found that the different concentrations of the sodium fluoride concentration in the process of reaction on the micro-arc oxidation reaction of spark ablation has certain control function.?2?Established the L₉?3⁴?orthogonal test table,and the thickness,micro hardness and surface roughness of the coating were used as the performance test indexes of WE54magnesium alloy ultrasonic micro arc oxidation coating,and optimized the process parameters.Based on the comprehensive analysis of the test indexes of concluded that current density size is 6A/dm²,pulse frequency of 700HZ,ultrasonic power is 100W,the thickness of coating,the micro hardness and the surface roughness to achieve the best.According to the analysis,the influence degree of the three parameters is:current density>ultrasonic power>pulse frequency.?3?Based on BP neural network technology,the data of orthogonal test table was used to establish BP network prediction model,and achieve the prediction of the thickness of ultrasonic micro-arc oxidation coating.Through the test and analysis,the imaging trend of the performance index of the coating is consistent with the experimental results.Therefore,the established model can be used to qualitative analysis of the ultrasonic micro-arc oxidation technology.?4?Study of ultrasonic cavitation effect of micro-arc oxidation process,the initial corrosion performance of the obtained coating was tested by the immersion test,after comparison found that the ultrasonic micro-arc oxidation coating was more resistant to corrosion than the micro-arc oxidation coating.By electrochemical workstation,achieve the polarization curves of the substrate material,the micro-arc oxidation coating and the ultrasonic micro-arc oxidation coating.The strength of corrosion resistance of each coating relative to the substrate material was compared through test data analysis.The corrosion resistance of the coating was measured in order:ultrasonic micro-arc oxidation coating>micro-arc oxidation coating>substrate material.