模拟孔溶液中球墨铸铁表面钝化膜脱钝过程及氯离子阈值分析

发布时间：2018-01-16 02:20

本文关键词：模拟孔溶液中球墨铸铁表面钝化膜脱钝过程及氯离子阈值分析　出处：《东南大学学报(自然科学版)》2017年02期 　论文类型：期刊论文

【摘要】：为了揭示输水过程中内衬水泥砂浆球墨铸铁管的腐蚀机理,开展了球墨铸铁样品在模拟砂浆孔溶液中的腐蚀实验.采用电化学测试方法,研究了模拟孔溶液中球墨铸铁表面钝化膜的脱钝过程,分析了模拟孔溶液碱度和氯离子浓度对球墨铸铁电化学阻抗谱及极化电阻的影响.结果表明:当模拟孔溶液的pH值从13.6降低至11.5时,球墨铸铁表面钝化膜脱钝时的氯离子浓度从0.30 mol/L减小至0,且脱钝时的球墨铸铁阻抗谱和极化电阻发生明显改变;球墨铸铁表面脱钝氯离子阈值与溶液的pH值呈线性关系,且随pH值的降低而减小.所建立的球墨铸铁表面脱钝氯离子阈值方程,为进一步评估内衬水泥砂浆球墨铸铁管的服役寿命提供依据.
[Abstract]:In order to reveal the corrosion mechanism of ductile iron pipes lined with cement mortar during water conveyance, the corrosion experiments of ductile iron samples in simulated mortar pore solution were carried out. The electrochemical test method was used. The desensitization process of the surface passivation film of nodular cast iron in simulated pore solution was studied. The effects of basicity of simulated pore solution and concentration of chloride ion on electrochemical impedance spectrum and polarization resistance of ductile iron were analyzed. The results showed that the pH value of simulated pore solution decreased from 13.6 to 11.5. The concentration of chloride ion decreased from 0. 30 mol/L to 0, and the impedance spectrum and polarization resistance of ductile iron were obviously changed when the passivation film was desensitized on the surface of ductile iron. The threshold value of desensitized chloride ion on the surface of ductile iron is linearly related to the pH value of the solution and decreases with the decrease of pH value. The threshold equation of desensitized chloride ion on the surface of ductile iron is established. It provides a basis for further evaluating the service life of ductile iron pipe lined with cement mortar.
【作者单位】：南京理工大学土木工程系;
【基金】：国家自然科学基金资助项目(51378262) 江苏省自然科学基金资助项目(BK20141396)
【分类号】：TG174.4
【正文快照】： 球墨铸铁管在城市供水、排水等各种水质输送工程中应用广泛,其耐久性直接影响到输水系统的服役性能和使用寿命[1].通过离心工艺,在球墨铸铁管内衬水泥砂浆保护层,避免水介质对球墨铸铁管的直接腐蚀作用,且水泥砂浆孔溶液的高碱性环境致使球墨铸铁表面形成钝化膜,可有效提高球

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