Abstract:

Failure behaviors of the organic coating system, zinc-rich epoxy primer/epoxy coating with mica iron/acrylic polyurethane topcoat, in corrosive media, including 3.5% NaCl solution, 3.5% NaCl solution + UV radiation, moist heat and salt spray, were studied with electrochemistry impedance spectra (EIS）.The relationships between coating resistance and phase angle were analyzed.The results indicated that phase angle at middle frequency of 10 Hz and coating resistance showed similar decreasing tendencies, hence these phase angle parameters may be used as quick measurements to evaluate coating performance.The order of the damaging effect of the four corrosive environments on carbon steel was 3.5% NaCl solution < salt spray < moist heat < 3.5% NaCl solution + UV radiation.

Key words:

有机涂层, 电化学交流阻抗法, 相位角

摘要：

用电化学交流阻抗法（EIS）研究了环氧富锌底漆/环氧云铁中间漆/丙烯酸聚氨酯面漆这一涂层体系在3.5%NaCl溶液、3.5%NaCl溶液+紫外辐射、湿热和盐雾这4种环境中的失效行为，探讨了特征频率下的相位角和涂层电阻值之间对应的关系。结果表明：中频区10 Hz处涂层相位角随时间的变化曲线和涂层电阻值随时间的变化曲线有良好的相似性，据此可以对所研究的涂层体系失效程度进行快速评价;所试验的4种腐蚀环境对所研究的涂层体系的破坏作用由小到大依次为：3.5% NaCl溶液<盐雾<湿热<3.5% NaCl溶液+紫外辐射。

关键词:

有机涂层, 电化学交流阻抗法, 相位角