电动汽车电机铝合金外壳大气腐蚀与防护仿真研究

Simulation Study on Atmospheric Corrosion and Protection of Aluminum Alloy Shell of Electric Vehicle Motor

基于大型仿真软件COMSOL Multiphysics,从温度、湿度两个方面对6063铝合金的大气腐蚀行为影响和牺牲镁阳极的阴极保护法进行仿真研究。结果表明:温度在0~120℃内对6063铝合金大气腐蚀影响并不大,温度与腐蚀程度呈正相关,在120℃腐蚀情况最严重,年腐蚀厚度均在1.48μm/a附近;相对湿度0.35~0.85范围内,腐蚀速率先平稳后降低再升高,在相对湿度为0.6时腐蚀情况最轻,在相对湿度为0.85时腐蚀情况最严重,年腐蚀厚度为38.684μm/a,并且随着时间的增加,腐蚀产物会减缓腐蚀的继续发生;采用镁作牺牲阳极的防护研究表明:相对湿度的变化对牺牲阳极保护法的腐蚀情况影响不大,电机外壳的电位均在保护电压范围内,说明在电动汽车电机铝合金外壳使用牺牲阳极的阴极保护方法得到了较好的保护效果。

Based on COMSOL Multiphysics,the effects of temperature and humidity on atmospheric corrosion behavior of 6063 aluminum alloy and cathodic protection of sacrificial magnesium anode were simulated.The results showed that temperature had a slight influence on atmospheric corrosion of 6063 aluminum alloy within 0~120℃,and there was a positive correlation between temperature and corrosion degree.The corrosion situation was the most serious at 120℃,and the annual corrosion thickness was around 1.48μm/a.When the relative humidity in the range of 0.35~0.85,the corrosion rate was first stable,then decreased,and then increased.The corrosion was the least severe at 0.6 relative humidity and the most severe at 0.85 relative humidity.The annual corrosion thickness was 38.684μm/a,and the corrosion products will slow down the occurrence of corrosion with the increase of time.Protective studies used magnesium as sacrificial anode showed that the change of relative humidity had a little effect on the corrosion of sacrificial anode protection,the potential of the whole motor shell was within the protection voltage range,which indicated that the cathode protection method of sacrificial anode used in the aluminum alloy shell of electric vehicle motor had a good protection effect.