飞机蒙皮结构表面涂层失效的电化学阻抗分析

Electrochemical Impedance Spectroscopy Analysis of Failure of Aircraft Surface Coating

采用冲击破坏、盐雾、紫外、湿热等加速循环腐蚀实验方法,对比分析了一种飞机蒙皮结构表面涂层在不同加速循环周期下的电化学阻抗谱(EIS)的变化特点。结果表明,涂层阻抗在腐蚀中后期增加,并出现新的时间常数,可对应于金属表面氧化膜的溶解及Al基体的腐蚀。随着腐蚀循环的进行,涂层的吸水量先增加后减少,吸水率最终稳定在约5%。

Adopt accelerate circulation corrosion test methods which include impact test, salt spray test, ultraviolet illumination test and humid heat test to analysis the characteristics of electrochemical impedance spectroscopy （EIS） on different accelerate circulation time. The EIS of coating increased in the middle and late stages, and new time constants took place, which could be related to resolving of the chemical conversion film and corrosion of the aluminum on the activation zone. The water absorbing capacity of coating were calculated and found increasing at first and then decreasing with increasing of accelerated circulation time, the water absorption rate finally stabilized at about 5%.