摘要
通过EIS研究了210℃下基体的预热时间对熔结环氧粉末涂层/Q345钢体系失效行为的影响,利用SEM和EDS对涂层底部金属表面的腐蚀产物进行了分析,探讨了涂层体系结合性能与涂层下金属基体腐蚀过程的相关性。结果表明,基体的预热时间对涂层体系结合性能影响显著,结合性能的差异导致涂层下金属基体腐蚀过程不同。基体预热时间为0和2 h时,涂层体系结合性能差,涂层/金属界面处富氧,涂层下金属腐蚀反应开始较早,阴极反应主要为O_2还原反应,金属基体腐蚀向纵深发展速率快,金属基体易发生点蚀;基体预热时间为6和12 h时,涂层体系结合性能好,涂层下金属腐蚀反应开始较晚,涂层/金属界面处贫氧,铁氧化物参与阴极反应,金属基体腐蚀横向发展快,更接近于均匀腐蚀行为。
The effect of substrate preheating time at 210 ℃ on the degradation behavior of fusion bonded epoxy powder coating/Q345 steel system was studied by electrochemical impedance spectroscopy（EIS）. The corrosion products of the substrate beneath the coating were characterized by means of scanning electron microscopy（SEM） and energy dispersive spectrometer（EDS）. Results showed that the substrate preheating time had a significant effect on the adhesion of the coating to the substrate,which led to the different corrosion behavior of the metal substrate beneath the coating. The coating exhibited poor bonding performance when the substrate preheating time was less than 2 h, which resulted in the occurrence of premature corrosion of the substrate metal. This might be due to the oxygen enrichment in the interface gap of coating/metal and the cathode reaction was mainly O2 reduction reaction. In this case, the corrosion of the substrate metal developed rapidly along the depth and the substrate metal was prone to pitting. When the substrate preheating time was 6 and 12 h, the coating showed good bond-ing performance and the corrosion reaction of the substrate metal beneath the coating happened much later. This could be supposed that the excellent adhesion of the coating made the oxygen deprivation at the interface of coating/metal and iron oxide was reduced in the cathode reaction. The corrosion of the substrate metal developed laterally and the corrosion behavior was closer to be uniform corrosion.
作者
曹海娇
魏英华
赵洪涛
吕晨曦
毛耀宗
李京
CAO Haijiao;WEI Yinghua;ZHAO Hongtao;LV Chenxi;MAO Yaozong;LI Jing(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2018年第3期255-264,共10页
Journal of Chinese Society For Corrosion and Protection
基金
中国科学院A类战略性先导科技专项(XDA13040500)~~
关键词
熔结环氧粉末涂层
预热时间
电化学阻抗谱
结合性能
金属基体腐蚀行为
fusion bonded epoxy powder coating
preheating time
electrochemical impedance spectroscopy
adhesion property
corrosion behavior of metal substrate
