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模拟混凝土失效不同时期的孔隙液环境,并通过循环极化曲线、电化学阻抗谱、M-S测试技术研究了304SS在模拟混凝土孔隙液中的耐蚀性。结果表明,在不同pH值以及不同Cl~-浓度模拟环境下,304SS钝化膜的耐蚀性随着pH值的降低以及Cl~-浓度的升高而降低;且在pH值为13的环境下钝化膜耐蚀性远高于pH值为9和11的,但在高pH值下孔蚀坑内流出的腐蚀产物会对钝化膜起破坏作用。通过电化学阻抗谱和M-S测试分析了不同pH值环境下钝化膜耐蚀性及其钝化膜半导体特征,表明在pH值为13的饱和NaCl环境下钝化膜电阻远高于pH值为9和11的,不同环境下304SS钝化膜在开路电位下均呈现N型半导体性质。表明海洋环境条件下,随混凝土碳化过程和Cl~-的富集造成的腐蚀环境改变会对304SS产生重要影响,304SS钝化膜稳定性降低,发生腐蚀的倾向性增加。
The pore fluid environment in different periods of failure of concrete was simulated, and the corrosion resistance of 304SS in simulated concrete pore fluid was studied by cyclic polarization curve, electrochemical impedance spectroscopy and M-S test. The results show that the corrosion resistance of 304SS passivation film decreases with the decrease of pH value and the increase of Cl ~ - concentration under different pH values and different Cl ~ - concentrations. Under pH = 13 The corrosion resistance of the lower passivation film is much higher than that of the pH 9 and 11, but the corrosion products flowing out of the pitting hole at high pH can damage the passivation film. The corrosion resistance of the passivation film and the characteristics of the passivating film semiconductor under different pH values were analyzed by electrochemical impedance spectroscopy and MS. The results showed that the resistance of passivation film was much higher than that of pH value under saturated NaCl environment of pH 13 9 and 11, the 304SS passivation film exhibits N-type semiconductor properties under open circuit potentials. It shows that under the marine environment, the change of corrosion environment caused by the carbonation process and Cl ~ - enrichment of concrete will have a significant impact on 304SS, the stability of 304SS passivation film decreases and the tendency of corrosion increases.