HRB400钢在模拟混凝土孔隙液中的自然钝化行为及耐蚀性能的研究

Natural Passivation Behavior and Corrosion Resistance of HRB400 Steel in Simulated Concrete Pore Solution

首先通过开路电位测试、电化学阻抗谱和Mott-Schottky曲线研究了HRB400钢在模拟混凝土孔隙液中的自然钝化行为,并结合XPS和AFM测试对钝化膜的成分与结构进行了分析,随后采用动电位极化曲线和SVET技术研究了自然钝化所形成的钝化膜的耐Cl^(-)侵蚀性能,并结合SEM测试对腐蚀形貌进行了微观分析。结果表明,HRB400钢在模拟混凝土孔隙液中形成稳定的钝化膜至少需要72 h,在该过程中,钝化膜的结构和成分随之发生改变。稳定的钝化膜具有很好的耐Cl^(-)侵蚀能力,临界Cl^(-)浓度范围为0.1~0.15 mol/L,这与微观组织的分析结果基本保持一致。

The natural passivation behavior of HRB400 steel in simulated concrete pore solution,i.e.a saturated Ca(OH)2 solution with pH 12.5 was investigated via measurements of open circuit potential,electrochemical impedance spectra,and Mott-Schottky curves.The composition and structure of the passivation film were characterized by X-ray photoelectron spectroscope and atomic force microscope.Subsequently,the resistance t Cl^(-) attack of the passivation film formed by the natural passivation in saturated Ca(OH)_(2) solution with varying pH values was further studied with dynamic potential polarization curve measurement,SVET technique,and SEM in terms of corrosion morphology and corrosion products.The results indicate that HRB400 steel requires at least 72 h to form a stable passivation film in simulated concrete pore solution,and the structure and composition of the passivation film are subsequently changed during the process.The stable passivation film exhibits excellent resistance to chloride ion attack with a critical chloride ion concentration range of 0.1 to 0.15 mol/L,which is well consistent with the results of SEM characterization.