典型防护涂层体系在南极大气环境中的失效行为研究

Failure Behaviour of Some Classical Protective Coatings in Antarctic Environments

目的研究南极多种特殊环境因素对典型有机涂层失效产生的具体作用。方法以在南极中山站现场暴露1 a的环氧树脂类、聚氨酯类涂层体系为研究对象,通过光泽度测试、色差测试、附着力测试、SEM、EIS、FTIR等方法系统地研究涂层的失效行为,以及中山站环境因素的作用机制。结果在环氧树脂类涂层表面有肉眼可见的剥落、起泡、微裂纹和坑状损伤,表现出比聚氨酯类涂层更加明显的失光、色差、附着力损失、化学结构变化等;电化学测试结果表明,6种涂层的无划叉试样在暴露1 a后防护性能均有所下降,其低频阻抗模值(|Z|_(0.01 Hz))下降了约1个数量级。其中,环氧树脂类涂层的划叉试样表现出更差的防护性能,其|Z|_(0.01 Hz)最大下降了5个数量级,最低达到4.02×10^(4)Ω·cm^(2),同时聚氨酯类涂层的|Z|_(0.01 Hz)仍保持在10^(11)Ω·cm^(2)左右。红外测试结果表明,环氧类涂层的部分官能团发生了水解反应,而聚氨酯类涂层没有发生明显的化学结构变化。此外,环氧涂层的附着力损失率较高,最高达到77%。结论南极中山站的高湿度、高盐度、强紫外线、强风、低温等环境因素对涂层的失效起到了重要作用。

The specific effects of various special environmental factors on the failure of typical organic coatings in Antarctica were studied.Epoxy resin and polyurethane coating systems exposed for 1 year at Zhongshan Station in Antarctica were regarded as experimental subjects.In this paper,the failure behavior of the coatings and the mechanism of environmental factors at Zhongshan Station were systematically investigated by means of gloss value tests,color difference tests,adhesion tests,SEM,EIS,FTIR,etc.The surface of the epoxy resin-based coatings showed flaking,blistering,micro-cracks and pit damage visible to the naked eye,and showed more obvious light loss,color loss,adhesion loss,chemical structure changes than polyurethane coating.In addition,the electrochemical test results showed that the protection performance of the six coatings without scratch decreased after 1 year of exposure,with a decrease of approximately 1 order of magnitude in|Z|_(0.01 Hz).The epoxy resin coated scratched specimens showed worse protection with a maximum drop of 5 orders of magnitude in|Z|_(0.01 Hz),reaching a minimum of 4.02×10^(4)Ω·cm^(2);in contrast,the aliphatic polyurethane coating still maintained its|Z|_(0.01 Hz)at around 10^(11)Ω·cm^(2),indicating that it still had good corrosion protection.The FTIR test results show that under the influence of the strong Antarctic UV environment,some of the functional groups of the epoxy-based coating underwent hydrolysis reactions,while the polyurethane coating did not undergo significant chemical structure changes.In addition,the epoxy coatings showed a high rate of adhesion loss,up to 77%,while the polyurethane coatings maintained a high level of adhesion in comparison.In general,the high humidity and salinity,strong UV,strong winds and low temperatures of the Antarctic Zhongshan Station play an important role in the failure of the coatings.