乙烯基硅烷处理的Q235钢在3．5％NaCl中腐蚀性的阻抗谱分析

从阻抗谱方面研究Q235钢硅烷处理的防腐蚀效果和成膜机理的报道较少。以不同浓度（1％～7％）、不同pH值（3～5）的乙烯基三乙氧基硅烷（VTES）水解液对Q235钢进行处理，利用电化学阻抗谱（EIS）分析了硅烷膜对3．5％NaCl溶液中Q235钢的防护效果及机理，并用红外光谱与扫描电镜（SEM）分析了Q235钢表面VTES膜的分子结构及其在盐水中浸泡腐蚀后的形貌。结果表明：VTES膜能明显改善Q235钢的耐蚀性能；经5％硅烷，pH=4的水解液处理形成的VTES膜在3．5％NaCl溶液中的电荷转移电阻及膜孔电阻最大，耐蚀效果最好，在3．5％NaCl溶液中浸泡5d后仍未发生腐蚀；Q235钢表面形成的硅烷膜既存在金属表面与硅醇单体的缩合，也有硅醇单体的缩合，还有未发生交联的Si-OH基团。

Electrochemical Impedance Spectroscopic Study of Corrosion Resistance of Vinyl Silane Deposited Film on Q235 Steel in Aqueous Sodium Chloride Solution

Q235 steel was treated in the hydrolytic solution of vinyltriethoxy silane(VTES) with different concentrations(1%～7%) and pH values(3～5).The protective effectiveness and mechanism of resultant VTES film for Q235 steel in 3.5% NaCl were investigated by means of electrochemical impedance spectroscopy.The molecular structure of VTES film and morphology of VTES film after being immersed and corroded in the saline solution were analyzed with an infrared spectrometer and a scanning electron microscope.It was found that as-prepared VTES film was able to drastically improve the corrosion resistance of Q235 steel.VTES film formed on Q235 steel at a vinyl silane concentration of 5% and pH value of 4 possessed the largest charge transfer resistance and film pore resistance,and was free of corrosion after being immersed in the saline solution for 5 d,showing good corrosion resistance.Moreover,VTES film formed on Q235 steel surface contained condensation polymerized product of metal surface and silanol monomer,condensation product of silanol monomer and unlinked Si-OH group.