物理化学学报 >> 2011, Vol. 27 >> Issue (04): 905-912.doi: 10.3866/PKU.WHXB20110336

电化学和新能源 上一篇    下一篇

烯胺阻锈剂对钢筋在模拟碳化混凝土孔隙液中的点蚀抑制

董泽华, 朱涛, 石维, 郭兴蓬   

  1. 华中科技大学化学与化工学院, 武汉 430074
  • 收稿日期:2010-09-26 修回日期:2010-12-20 发布日期:2011-03-29
  • 通讯作者: 董泽华 E-mail:zehua.dong@gmail.com
  • 基金资助:

    国家自然科学基金(50971064)资助项目

Inhibition of Ethyleneamine on the Pitting Corrosion of Rebar in a Synthetic Carbonated Concrete Pore Solution

DONG Ze-Hua, ZHU Tao, SHI Wei, GUO Xing-Peng   

  1. School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
  • Received:2010-09-26 Revised:2010-12-20 Published:2011-03-29
  • Contact: DONG Ze-Hua E-mail:zehua.dong@gmail.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50971064).

摘要:

通过电化学噪声(ECN)、电化学阻抗(EIS)及极化曲线研究了四乙烯五胺(TEPA)在碳化模拟混凝土孔隙液中对Q345B碳钢点蚀的抑制机理. 结果表明: 通过吸附成膜和隔离Cl-离子对钝化膜的侵蚀, TEPA浓度升高导致碳钢点蚀电位正移. 低浓度的TEPA会造成亚稳态蚀点形核速率略微增加, 但会降低其寿命. 随着TEPA浓度增加, 噪声电阻上升, 而亚稳态蚀点寿命和平均点蚀电量则迅速下降, 表明其明显加速了亚稳态蚀点修复, 当TEPA浓度达0.10 mol·L-1时, 噪声峰消失, 基底电流趋于零, 蚀点全面钝化. TEPA不仅能抑制Cl-离子引起的亚稳态和稳态蚀点生长, 还可吸附于钝化膜表面, 抑制膜的均匀溶解. 形貌观察表明, 亚稳态蚀点主要在稳态蚀点周围形核和生长, 并不断为稳态蚀点所吞并, 造成碳钢表面蚀坑一般沿平面而不是垂直方式扩展.

关键词: 碳钢, 点蚀, 缓蚀剂, 混凝土孔隙液, 电化学噪声

Abstract:

Tetraethylenepentamine (TEPA) was surveyed to show strong inhibition on pitting corrosion of Q345B carbon steel in a carbonated synthetic pore solution (SPS) by electrochemical noise (ECN), electrochemical impedance spectroscopy (EIS), and polarization curves. The pitting corrosion potential shifts positively with an increase in the TEPA concentration. ECN data show that the low content of TEPA can increase the nucleation rate of the metastable pits slightly and can effectively reduce their lifespan. The high content (0.10 mol·L-1) of TEPA accelerates the repassivation of metastable pitting and this is accompanied by an increase in noise resistance and a decrease in the nucleation rate and average pitting charge until the noise current transients disappear completely. Both the baseline current and the amplitude of the current transients decrease with an increase in the TEPA concentration, indicating that TEPA retards not only the pitting corrosion but also the general dissolution of the passive film. Micrographs show that the metastable pits mainly initiate and develop around the stable pits because of the induction of corrosion products, which causes the pitting cavity on carbon steel to grow generally in a planar rather than in a perpendicular direction.

Key words: Carbon steel, Pitting corrosion, Inhibitor, Concrete pore solution, Electrochemical noise

MSC2000: 

  • O646