NO_3^-/NO_2^-插层MgAl-LDHs在混凝土模拟孔溶液中的阻锈性能  

Anti-corrosion performance of NO_3^-/NO_2^- intercalation of MgAl-LDHs in simulated concrete pore solution

作　　者：宋迎宾 徐金霞[1] 蒋林华[1] 谭启平 梅友静 SONG Ying-bin;XU Jin-xia;JIANG Lin-hua;TAN Qi-ping;MEI You-jing(College of Mechanics and Materials,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学力学与材料学院,江苏南京210098

出　　处：《浙江大学学报（工学版）》2018年第12期2397-2405,共9页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金面上资助项目(51478164);江苏省自然科学基金资助项目(BK20181306)

摘　　要：通过共沉淀法合成硝酸根插层镁铝层状双金属氢氧化物MgAl-NO_3LDHs(简称LDHs-NO_3),以其为主体,由离子交换制备亚硝酸根插层双金属氢氧化物MgAl-NO_2 LDHs(简称LDHs-NO_2).通过对比试验,采用等温吸附法、自腐蚀电位和电化学阻抗谱(EIS)研究所制备的LDHs-NO_3、LDHs-NO_2在混凝土模拟孔溶液中对氯离子的吸附性能及其对钢筋的阻锈作用;采用扫描电镜(SEM)、X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)揭示其阻锈机理.结果表明:LDHs-NO_2的最大氯离子吸附量为2.51 mmol/g,与LDHs-NO_3相差不大,展现出良好的氯离子吸附性能;LDHs-NO_2具有比LDHs-NO_3更好的阻锈效果,可以明显提高钢筋在混凝土模拟孔隙液中的临界氯离子浓度值;LDHs-NO_2良好的阻锈性能源于对氯离子的吸附和阻锈离子NO_2^-的释放,对钢筋产生双重阻锈作用,同时有效阻锈成分NO_2^-逐步释放,可以为钢筋提供长期的保护作用.Mg-Al-NO2 LDH(LDHs-NO2)was synthesized by anion exchange in the host materia;Mg-Al-NO3 LDH(LDHs-NO3)was prepared by coprecipitation method.By a comparative experiment,the inhibitive effect of LDHs-NO3 and LDHs-NO2 on the corrosion resistance performance of steel in simulated concrete pore solution were investigated by means of chloride equilibrium isotherm,corrosion potential and electrochemical impedance spectroscopy(EIS).Besides,scanning electron microscopy(SEM),X-ray diffraction instrument(XRD)and infrared spectroscopy were applied to observe the morphologies and microstructures of LDHs.Results show that the maximum chloride adsorption capacity of LDHs-NO2 is 2.51 mmol/g,which is similar with that of LDHs-NO3,indicating good adsorption property of chloride ion;LDHs-NO2 has better inhibition effect than LDHs-NO3,which can significantly increase the chloride threshold value of steel in the simulated concrete pore solution.The good anticorrosion performance of LDHs-NO2 is because of the chloride ions adsorption and the release of NO2^-in the interlayer,which provides dual effect of anti-corrosion performance for steel bar.At the same time,the effective corrosion resistance component NO2^-is released gradually,which can provide long-term protection for steel bar.

关 键 词：双金属氢氧化物 亚硝酸根插层 混凝土模拟孔溶液 氯离子吸附 阻锈性能 

分 类 号：TU528.042[建筑科学—建筑技术科学]