带损伤环氧涂层钢筋在Cl^-和碳化耦合作用下的腐蚀行为  

Corrosion Behavior of Damaged Epoxy Coated Steel Bars Under the Coupling Effect of Chloride Ion and Carbonization

作　　者：魏洁[1] 魏英华[2] 李京[2] 赵洪涛[2] 吕晨曦[2] 董俊华[1] 柯伟[3] 何小燕 WEI Jie;WEI Yinghua;LI Jing;ZHAO Hongtao;LV Chenxi;DONG Junhua;KE Wei;HE Xiaoyan(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Shenyang Research and Development Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Environmental Corrosion Center,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所沈阳材料科学国家研究中心,沈阳110016 [2]中国科学院金属研究所沈阳先进材料研发中心,沈阳110016 [3]中国科学院金属研究所材料环境腐蚀研究中心,沈阳110016

出　　处：《金属学报》2020年第6期885-897,共13页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51501201;中国科学院A类战略性先导科技专项项目No.XDA13040501;沈阳市重大科技成果转化项目No.Z17-7-021。

摘　　要：通过与裸钢筋和完好涂层钢筋对比,研究了带损伤环氧涂层钢筋在Cl^-和碳化耦合作用下的腐蚀演化行为。在表征环氧涂层组成与结构特征的基础上,采用CLSM及Raman光谱分析涂层损伤处的腐蚀形貌及产物组成;采用腐蚀电位与电化学阻抗谱监测腐蚀过程,揭示腐蚀演化动力学规律。结果表明,无预制损伤的环氧涂层对钢基体具有良好的保护作用,在6种Cl^-及碳化侵蚀性环境中长期浸泡均未发生腐蚀。预制损伤涂层钢筋试样的腐蚀活化/钝化行为与未涂装的裸钢筋一致,均明显地受Cl^-和碳化影响。在无Cl^-且pH值为12.6和9.8的溶液中发生钝化;在无Cl^-且pH值为9.2的溶液以及0.6 mol/L NaCl的不同p H值溶液中均发生活化溶解,且腐蚀速率随时间延长呈增加趋势。在不含Cl^-溶液中,长期腐蚀后的腐蚀产物主要为α-FeOOH;而在不同pH值的含Cl^-溶液中,其腐蚀产物除α-FeOOH之外,还含有β-FeOOH及少量Fe3O4。在Cl^-和碳化耦合作用下,预制损伤涂层钢筋的腐蚀仅发生在损伤部位,腐蚀向基体深处扩展,不会造成其它部位涂层的剥离。It is unavoidable for coated steel bars to be scratched during transportation and construction,which will lead to the damage of coating and exposure of steel matrix.Consequently,the corrosion resistance of coated steel bars after damage will directly affect the durability of structures.The corrosion evolution behavior of damaged epoxy coated steel bars under the coupling action of chloride ion and carbonization was studied by comparing with bare steel bars and perfectly coated steel bars.On the basis of characterizing the composition and structural characteristics of epoxy coating,the corrosion morphology and product composition at the damage site of the coating were analyzed by CLSM and Raman spectroscopy,and the corrosion process was monitored by corrosion potential and electrochemical impedance spectroscopy to reveal the dynamic of corrosion evolution.The results show that the epoxy coating without damage has a good protective effect on steel matrix,and no corrosion occurs during long-term immersion in all six solutions including the chloride ions and carbonization corrosive environments.The corrosion activation or passivation behavior of damaged coated steel bars is consistent with that of uncoated bare bars,which is obviously affected by chloride ion and carbonization.Passivation occurs in the system without Cl^- and with pH of 12.6 or 9.8.Activation dissolution occurs in the chloride-free system with pH of9.2,and in the system of different p H values with 0.6 mol/L NaCl.In the active systems,the corrosion rate increases with time.In the chloride-free system,the corrosion products after long-term corrosion are mainly α-FeOOH,while in the chloride-containing system with different pH,the corrosion products contain not only α-FeOOH,but also β-FeOOH and a small amount of Fe3 O4.Under the coupling action of chloride ion and carbonization,the corrosion of damaged coated steel bars occurs only in the damaged site,and the corrosion extends towards to the depth of the matrix,which will not cause the peeling of coa

关 键 词：环氧涂层钢筋 腐蚀演化 Cl^- 碳化 

分 类 号：TG172.2[金属学及工艺—金属表面处理]