环氧粉末涂层在1.5mol/LNaCl溶液中的失效行为

Degradation Behavior of Fusion Bonded Epoxy Powder Coating on Q235 Carbon Steel in 1.5 mol/L NaCl Solution

通过电化学阻抗谱(EIS)对两种环氧粉末涂层在1.5 mol/LNaCl溶液中的失效行为进行了研究,利用扫描电子显微镜(SEM)和能谱仪(EDS)对涂层底部金属表面的腐蚀产物进行了分析,探讨了环氧粉末涂层在1.5 mol/L NaCl溶液中的失效机理。结果表明,在1.5 mol/L NaCl溶液中,Cl-等腐蚀介质能在涂层中形成传输通道渗透到涂层与金属界面,并参与界面的腐蚀反应,腐蚀产物主要为Fe的氧化物和氯化物。

The degradation behavior of two kind of fusion bonded epoxy coatings on Q235 carbon steel in 1.5 mol/L NaCl solution was investigated by electrochemical impedance spectroscopy(EIS)and scanning electron microscope(SEM) with energy dispersive spectrometer(EDS). The results showed that corrosive species(Cl-etc) could penetrate through the coating and then arrive at the interface of coating/Q235 carbon steel,which then induced corrosion reaction there, resulting corrosion products composed mainly of iron oxide and iron chloride. Finally a three step process was proposed to describe the electrochemical process of the coating degradation.