摘要
采用电化学工作站、SEM、XRD等技术研究了A572Gr.65钢在pH4~10之间的土壤模拟液中的腐蚀行为,探讨了酸性和碱性溶液对A572Gr.65钢耐蚀性能的影响。结果表明:随着pH增大,A572Gr.65钢的极化电阻随之增加,且自腐蚀电位正移,自腐蚀电流密度减小,在碱性溶液中A572Gr.65钢表现出最佳的耐蚀性能。当溶液为酸性时,腐蚀产物主要为γ-FeOOH。高浓度的H^(+)会促进感抗弧的产生,使A572Gr.65钢表面的钝化膜遭到破坏,并且H^(+)在反应过程中会生成氢气,造成腐蚀产物的疏松,在此过程中阴极的析氢反应为整个过程的限制性环节;当pH为中性或碱性时,OH^(-)会促进γ-FeOOH向更加致密的Fe_(3)O_(4)和α-FeOOH转化,致密的腐蚀产物会阻碍侵蚀性离子和溶解氧的扩散,从而保护基体。此时金属表面腐蚀活性点的形成以及阳极的溶解速度为整个过程的限制性环节。
The corrosion behavior of A572 Gr.65 steel in various artificial soil solutions was studied by means of electrochemical workstation, scanning electron microscopy(SEM), X-ray diffractometer(XRD) and other techniques. The results show that with the increase of pH value, the polarization resistance of A572 Gr. 65 steel also increases, meanwhile the free-corrosion potential of A572 Gr. 65 steel moves positively, while the free-corrosion current density decreases. The corrosion resistance of steel in alkaline solution is the best. When the solution is acidic, the main corrosion product is γ-FeOOH. High concentration of H^(+)can promote the generation of impedance arc and destroy the passive film on the surface of A572 Gr.65 steel. In addition, H^(+)will generate hydrogen in the reaction process, make corrosion products loose, and accelerate the corrosion process. In this process, the hydrogen evolution reaction of cathode is the controlling step for the whole process. When the pH value becomes neutral or alkaline gradually, OH^(-)will promote the transformation of γ-FeOOH to dense Fe_(3)O_(4) and α-FeOOH. The dense corrosion products will hinder the diffusion of corrosive ions and dissolved oxygen, protect the substrate effectively and slow down the progress of corrosion. In this process, the formation of corrosion active points on the metal surface and the dissolution rate of anode are the controlling step for the whole process.
作者
丁聪
张金玲
于彦冲
李烨磊
王社斌
DING Cong;ZHANG Jinling;YU Yanchong;LI Yelei;WANG Shebin(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2022年第1期149-155,共7页
Journal of Chinese Society For Corrosion and Protection
基金
国家自然科学基金(52004180)
山西省面上青年基金(201801D221138)。
关键词
A572Gr.65钢
极化曲线
阻抗谱
PH
腐蚀动力学
土壤腐蚀
A572Gr.65 steel
polarization curve
electrochemistry impedance spectroscopy
pH value
corrosion kinetics
soil corrosion
