饱和NaCl溶液浸泡下混凝土试块中有机阻锈剂对钢筋腐蚀行为的影响

Influence of Organic Inhibitors on the Corrosion Behavior of Steel Rebar inside Mortar Specimens Immersed in Saturated NaCl Solution

利用电化学阻抗谱(EIS)、半电池腐蚀电位(Ecorr)和宏观电池腐蚀电流密度(Icorr)测量技术,在饱和NaCl溶液浸泡的硬化混凝土试块中,研究了4种醇胺基阻锈剂对钢筋电极腐蚀电化学行为的影响和长期阻锈性能.在浸泡初始的100d内,与空白样相比,添加阻锈剂后钢筋电极腐蚀电位升高,阻抗膜值增大,腐蚀电流密度值降低,表明电极表面处于钝态,阻锈剂表现出良好的阻锈性能.随浸泡时间延长,电极腐蚀电位和阻抗膜值下降,腐蚀电流密度增大.浸泡后期,除添加醇胺基CI-4样外,电极电位和腐蚀电流密度与空白样相比无明显差别,表明电极由钝态转变为活性腐蚀状态.但添加CI-4样品,钢筋电极始终保持在钝化状态,阻锈性能最好.基于阻锈剂与Cl-间的竞争吸附,分析探讨了可能的阻锈机理.

The long-term effects of four kinds of amine-alcohol based inhibitors on the corrosion behavior of steel rebar inside mortar specimens immersed in saturated NaCl solution were studied by electrochemical impendence spectroscopy（EIS）,half cell corrosion potential（Ecorr）,and macrocell corrosion current density（Icorr） measurements.We found that the Ecorr and the impedance modulus were higher than those in the control specimen after inhibitor addition.Additionally,Icorr decreased over the initial 100 d of immersion revealing that the steel rebar electrodes are kept in passive state and the inhibitors showed good inhibition effects.With an increase in the immersion time,Ecorr and the impedance modulus for all the inhibited mortar specimens decreased while Icorr increased.After immersion for 125 d there were no obvious differences between Ecorr and Icorr for the inhibited systems by comparison to those in the blank sample,except for the specimen containing CI-4.This suggests that the surface of the electrode changes from passive state to active state.The best inhibition was obtained in the presence of the CI-4 inhibitor.We briefly discuss the inhibition mechanism based on the competitive adsorption of the inhibitor molecules with Cl-on the steel rebar surface.