涂层酸性盐雾环境下失效过程的电化学阻抗谱分析

EIS Analysis on Coating Failure Process in Acidic Salt Spray Environment

目的探究车辆装备有机涂层在沿海地区酸雨污染环境下的腐蚀行为。方法利用电化学阻抗谱技术,对金属漆涂层酸性盐雾环境下的腐蚀失效过程进行研究,分析其电化学阻抗谱特征及涂层电容的变化规律,并利用10 Hz下的中频相位角(θ_(10))和阻抗模值(|Z|_(10))评价金属漆涂层的防护性能。结果金属漆涂层的腐蚀失效过程大致经历3个阶段,即涂层完好阶段、涂层防护性能下降阶段和涂层失效阶段,随着腐蚀时间的增加,涂层电容逐渐增大,当θ10<28.78°,|Z|10<1.78×10~7?·cm^2时,涂层基本丧失腐蚀防护能力。结论利用中频相位角和阻抗模值可以有效地评价金属漆涂层酸性盐雾环境下的腐蚀防护性能,为车辆装备在沿海地区的腐蚀防护提供技术支撑。

The work aims to study the corrosion behavior of vehicle organic coating in the environment of coastal areas polluted by the acid rain. The corrosion failure process of metal paint coating in the acid salt spray environment was studied in electrochemical impedance spectroscopy（EIS） method. The change law of EIS features and the coating capacitance were analyzed. The intermediate frequency phase angle（θ_（10）） and impedance magnitude（｜Z｜_（10）） were used to evaluate the protective performance of the coating. The corrosion failure process of metal paint coating had gone through three stages： the undamaged coating, the reduced protective performance of coating and the coating failure. The coating capacitance gradually increased with the increasing corrosion time. When θ1028.78° and ｜Z｜101.78×10~7 ？·cm^2, the coating basically lost its ability to protect against the corrosion. With θ_（10） and ｜Z｜_（10）, the corrosion protection performance of metal paint coating in acid salt spray environment can be effectively evaluated, so as to provide the technical support for the corrosion prevention of military vehicles in the coastal areas.