东南沿海电厂钢结构涂层失效分析  

Failure Analysis of Steel Structure Coatings in a Southeast Coastal Power Plant

作　　者：郑观文 吴国威[1] 郑国[1] 王强 邓培昌 ZHENG Guan-wen;WU Guo-wei;ZHENG Guo;WANG Qiang;DENG Pei-chang(Zhanjiang Power Co.,Ltd.,Zhanjiang 524099,Guangdong,China;College of Chemistry and Environment,Guangdong Ocean University,Zhanjiang 524088,Guangdong,China)

机构地区：[1]湛江电力有限公司,广东湛江524099 [2]广东海洋大学化学与环境学院,广东湛江524088

出　　处：《中国涂料》2024年第3期69-74,共6页China Coatings

基　　金：企业资助技术开发项目(ZJP-PY-H2022-121)。

摘　　要：针对沿海电厂钢结构涂层失效的分析,可为防腐材料选择、防腐方案的制定提供重要依据。利用便携式显微镜观察现役涂层宏观缺陷;利用胶带纸法粉化等级评定、傅里叶变换红外光谱(FT-IR)分析、电化学交流阻抗(EIS)测试判断涂层微观缺陷;利用简化的“接触角测定法”测定涂层表面疏水性。结果表明,涂层存在夹杂气泡破裂和填料脱落导致的孔洞缺陷,涂层/基体的热膨胀系数不匹配导致的裂纹缺陷,碰撞、弯折导致的裂缝缺陷等宏观缺陷;经一定时间暴露后,涂层成膜高分子降解、光老化导致微观缺陷;新涂制涂层材料具有一定的疏水性,经工业海洋大气环境暴露,疏水性迅速下降。由此可得,涂层表面滞留的液态水溶出灰尘中的可溶盐、吸附和吸收大气中的盐微粒和氧气,经涂层缺陷输运至涂层/金属界面,促成钢铁电化学腐蚀发生。涂层/金属界面的腐蚀产物累积,腐蚀产物体积效应导致涂层鼓泡、开裂、剥离,直至涂层完全失效。The failure analysis of coatings can provide an important basis for the selection of anti-corrosion materials and the formulation of anti-corrosion schemes.A portable microscope was used to observe the macroscopic defects of coatings.The microscopic defects of coatings were determined by the“tape paper pulverization grade evaluation”,the Fourier Transform Infrared Spectroscopy(FT-IR)and the Electrochemical Impedance Spectra(EIS).The surface hydrophobicity of coatings was measured by a simplified contact angle method.The results show the coatings have macroscopic defects such as hole defects caused by the bursting of inclusion bubbles and the falling off of fillers,crack defects caused by the mismatch of thermal expansion coefficient of coatings/substrate,and crack defects caused by collision and bending.After exposure for a certain time,the degradation and photoaging of the coatings film leads to the microscopic defects.The newly applied coatings material has certain hydrophobicity,and the hydrophobicity decreases rapidly after exposure to industrial marine atmospheric environment.The retained liquid water on the surface of coatings dissolves the soluble salt in the dust,and absorbs salt particles and oxygen in the atmosphere.The electrochemical corrosion of steel initiates when the retained liquid water reaches to the coatings/metal interface through the macro and micro defects of the coatings.The accumulation of corrosion products at the coatings/metal interface results in the bubbling,cracking,peeling off and failure of coatings.

关 键 词：涂层缺陷 海洋大气环境 涂层降解 疏水性 

分 类 号：TQ639.8[化学工程—精细化工] TG174[金属学及工艺—金属表面处理]