钼酸钠和三乙醇胺对Q235碳钢小孔腐蚀的抑制作用

通过动电位扫描,微区电位扫描,电化学阻抗谱及XPS等技术,考察了Na₂MoO₄和三乙醇胺 (TEA) 复配缓蚀剂对Q235碳钢孔蚀的抑制作用。结果表明：Q235碳钢在0.02 mol/L NaCl+0.1 mol/L NaHCO₃溶液中,适量的Na₂MoO₄与TEA复配对其孔蚀的抑制作用要优于单独使用Na₂MoO₄对孔蚀的抑制效果。在外加恒电位为0.3 V时,在实验溶液中碳钢表面有活性点被激活,Na₂MoO₄+TEA复配缓蚀剂能够明显抑制表面活性点的生成,并且能使形成的活性点的电位峰值迅速降低,抑制其向腐蚀小孔的转化。在加有Na₂MoO₄+TEA复配缓蚀剂的实验溶液中形成的缓蚀膜主要成分为Fe₂(MoO₄)₃,Fe₂O₃和TEA,三乙醇胺的吸附可以改善钼酸盐缓蚀膜的致密性,进一步提高缓蚀性能。

Inhibition Effect of Na2MoO4 and Triethanolamineon Pitting Corrosion of Q235 Carbon Steel

Effect of Na₂MoO₄ and triethanolamine (TEA) on pitting corrosion inhibition of Q235 carbon steel was studied with methods of potentiodynamic polarization, microcell potential scanning, EIS and XPS etc. The results show that when Na₂MoO₄ is compounded with TEA the pitting potential E_b of the steel in 0.02 mol/L NaCl+0.1 mol/L NaHCO₃ solution is obviously increased. Under an applied potential of 0.3 V, some potential peaks are observed at active sites on the surface, and the compound of Na₂MoO₄+TEA can effectively inhibit the number of the active sites and decrease the intensity of the potential peaks. In the solution with Na₂MoO₄ and TEA, the formed inhibition film on steel surface is composed of mainly Fe₂(MoO₄)₃, Fe₂O₃ and TEA. The adsorption of TEA may improve the compactness of the inhibition films induced by Na₂MoO₄ and further increase the inhibition effect.