Abstract:

The failure process of zinc-rich epoxy/chlorinated rubber coatings on Q235 steel was investigated by electrochemical impedance spectroscopy (EIS)In the initial period of exposure, EIS spectra showed that the protection effect of the coatings mainly came from the chlorinated rubber topcoatBut after a longer time of exposure, by increasing the zincrich epoxy primer thickness properly, the porosity of the coatings, the diffusion rate of ions and the absorbance of water in the coatings decreased remarkablyThe best protection was obtained for the coating systems with the thickness ratio of primer/topcoat about 2∶1For the systems of single primer or single topcoat, the protection effect of the coatings decreased quickly.

Key words:

电化学阻抗谱, 涂层, 紫外线, 腐蚀, 厚度

摘要： 采用环氧富锌作为底漆、氯化橡胶作为面漆，研究了涂层体系腐蚀过程中电化学阻抗谱(EIS)的变化。结果表明，腐蚀初期环氧富锌/氯化橡胶涂层体系中底漆的厚度比例与涂层的防护性能无关，而在腐蚀中后期，随底漆厚度比例适当增大，涂层自修复能力增强，离子等腐蚀介质在涂层中的传输速度得到显著延缓，涂层吸水率和孔隙率明显降低，涂层防护性能出现短时间升高。当环氧富锌底漆为涂层总厚度的2/3左右时，涂层体系的防护性能最好，而仅有底漆或面漆的体系则不具备良好的防护性能。

关键词:

电化学阻抗谱, 涂层, 紫外线, 腐蚀, 厚度