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利用交流阻抗谱和极化曲线研究比较了四组不同晶粒尺寸的螺纹钢在模拟海水液(3.5%NaCl)中短期电化学腐蚀行为;利用硼酸缓冲液中钝化膜的Mott-Schottky理论比较了各试样在不同阳极极化电位下的钝化膜的优劣性.结果表明,在14 d的模拟海水短期浸泡期间,细晶粒螺纹钢在后期表现出较大阻抗值和较小的自腐蚀电流密度,耐蚀性能优于粗晶粒试样.在硼酸缓冲液中形成的钝化膜表现出典型的n型半导体性能,公共钝化区间为-0.15～0.8 V.在选取的-0.1,0.2,0.5 V三个不同极化电位下,细晶粒螺纹钢在硼酸缓冲液中的钝化膜稳定性、耐蚀性弱于粗晶粒螺纹钢.在0.5 V的外加电压下试样钝化膜的内层膜消失,钝化膜的施主浓度最低,膜最为致密、稳定.
Short-term electrochemical corrosion behavior of four groups of rebar with different grain sizes in simulated seawater (3.5% NaCl) was compared using AC impedance spectroscopy and polarization curves. Mott-Schottky’s theory of passivation films in borate buffer was compared The results showed that during the short-term immersion in simulated seawater for 14 d, the fine-grained rebar showed larger values of impedance at the later stage and smaller The self-corrosion current density and corrosion resistance are superior to the coarse-grained samples.The passivation film formed in boric acid buffer shows typical n-type semiconductor properties with a common passivation interval of -0.15 ~ 0.8 V. In the selected - 0.1,0.2,0.5 V three different polarization potential, the fine grain rebar in the boric acid buffer passivation film stability, corrosion resistance is less than the coarse grain rebar test at an applied voltage of 0.5 V The inner film of the passive film disappears, the donor concentration of the passivation film is the lowest, the film is the most compact and stable.