静电喷涂聚酰亚胺涂层的防腐蚀性能

Corrosion Resistance of Polyimide Coating Prepared by Electrostatic Spraying Technique

聚酰亚胺(PI)在防腐蚀方面前景良好,但目前国内报道不多。采用静电喷涂的方法在N80钢表面制备了一种聚酰亚胺防腐蚀涂层。通过盐雾试验、浸泡试验评价了涂层在不同腐蚀环境中的耐蚀性能;通过硬度测试和抗冲击试验评价了涂层的力学性能;采用红外光谱、电化学方法交流阻抗、扫描电镜(SEM)、能谱(EDS)等方法研究了涂层的失效过程。结果表明:涂层耐盐雾性能良好,3 080 h盐雾试验后仅表面发生微观物理破坏,在人工划痕处产生少量腐蚀产物;涂层在3.5%NaCl溶液和25%HCl溶液中耐蚀性能优异,电化学性能不随时间发生显著变化,但在涂层表面产生少量微观缺陷;涂层力学性能良好,但提高腐蚀介质温度会使得力学性能下降。

A polyimide coating was prepared on the surface of carbon steel by using electrostatic spraying technique. The salt spray test and im- mersion test were carried out to evaluate the corrosion resistance of the coating in different corrosion environments. The mechanical property of the coating was measured by hardness test and impact resistant experiments. The degradation process of the coating was studied by infrared spectroscopy, electrochemical impedance spectrum （EIS） measurement, scanning electron microscopy （SEM） and energy dispersive spectrometer （EDS）. Results showed that the coating showed good corrosion resistance after the salt spray test of 3 080 h. The non-penetrated micro-cracks were found only on the surface and some corrosion products appeared in artificial scratches. The coating in 3.5% NaCI and 25% HC1 solutions had excellent corrosion resistance and their electrochemical performance did not change significantly over time, however, a few of micro defects were found on its surface. Furthermore, the coating displayed a great mechanical property, while increasing the temperature of corrosive solution reduced its mechanical property.