大气干湿交替环境下储罐涂层失效过程研究  

Study on coating failure of storage tank under alternating dry⁃wet atmosphere

作　　者：徐志鹏 XU Zhipeng(Zhejiang Petroleum Storage and Transportation Co.,Ltd.,Hangzhou 310051,China)

机构地区：[1]浙江浙石油储运有限公司,浙江杭州310051

出　　处：《石油化工腐蚀与防护》2023年第4期11-14,共4页Corrosion & Protection In Petrochemical Industry

摘　　要：涂层是储罐壁板外腐蚀防护的关键手段,然而在长时间的运行过程中涂层容易发生劣化,引起罐体金属的严重腐蚀。针对大气干湿交替环境,通过电化学试验方法和涂层微观形貌表征研究了储罐涂层的失效过程。结果表明,随着试验时间的增加,带涂层Q235钢的开路电位和腐蚀电位正向偏移,腐蚀电流密度增大,腐蚀由阴极控制逐渐转变为混合控制,电容(Q和Q_(dl))增加,电阻(R_(p)和R_(ct))减小,表明涂层防护效果逐渐减弱直至失效。电化学试验结果和涂层微观形貌表明,当试验进行18 d时,涂层表面粗糙度显著增加,甚至涂层表面产生明显的裂缝,表面涂层结构已被完全破坏,金属基体发生活化腐蚀过程。Coating was a key method of external corrosion protection for tank wall,but it was easy to deteriorate during the long running process,resulting in serious corrosion of the tank.Therefore,the failure process of tank coating was studied by electro⁃chemical experiment and coating morphology characterization in alternating dry⁃wet atmosphere.The results revealed that with the extension of experiment time,the open⁃circuit potential and corrosion potential of coated Q235 steel shifted forward,the corrosion current density intensified,the corrosion control gradually changed from cathode control to mixed control,the capacitance(Q and Q_(dl))enlarged and the resistance(R_(p)and R_(ct))decreased,indicating that the protective effect of coating gradually weakened until it failed.The electrochemical results and the morphology of the coating showed that the surface roughness of the coating increased significantly,and even obvious cracks appeared on the surface of the coating on 18th day,suggesting that the structure of the sur⁃face coating was completely destroyed,and the Q235 steel was corroded.

关 键 词：大气腐蚀 干湿交替环境 储罐涂层 电化学 形貌表征 

分 类 号：TE988[石油与天然气工程—石油机械设备]