车轮钢ER8在中性NaCl溶液中的电化学腐蚀行为

Electrochemical Corrosion Behavior of ER8 Wheel Steel in Neutral NaCl Solution

为研究ER8车轮钢在沿海中性氯盐环境下的腐蚀行为,通过电化学测试、腐蚀失重试验,结合扫描电镜(SEM)、X射线衍射(XRD)技术对ER8车轮钢在3种不同浓度中性NaCl溶液中的电化学腐蚀行为进行分析。极化曲线结果表明浸泡初期5.0%NaCl浓度下自腐蚀电流密度(Jcorr)最大,576 h后Jcorr在2.0%、3.5%NaCl浓度下均持续增大,腐蚀速率在2160 h时均大于0.12 mm/a。SEM结果显示腐蚀产物形貌主要为片状与团簇状结构,初期腐蚀产物形貌具有较多孔隙,难以阻碍Cl-与基体发生反应,2160 h时腐蚀产物结构更为均匀致密。XRD结果表明腐蚀产物主要由γ-FeOOH、α-FeOOH与Fe3O4组成。

In order to study the corrosion behavior of ER8 wheel steel in coastal neutral chlorine salt environment,the electrochemical corrosion behavior of ER8 wheel steel in neutral NaCl solutions with three different concentrations were analyzed through electrochemical tests,corrosion weight loss tests,scanning electron microscopy(SEM)and X-ray diffraction(XRD)techniques.The polarization curve results showed that the self-corrosion current density(Jcorr)was the largest in 5.0%(mass fraction,the same below)NaCl solution at the initial stage of immersion.After immersed for 576 h,Jcorr continued to increase at 2.0%and 3.5%NaCl solutions,and the average corrosion rate was more than 0.12 mm/a for 2160 h.The SEM results indicated that the morphology of corrosion products were mainly flake and cluster structures.Because the morphology of corrosion products at the initial stage had more pores,it’s difficult to prevent Cl-from reacting with the substrate.The structure of corrosion products was more uniform and denser for 2160 h.Moreover,the XRD results showed that the corrosion products were mainly composed of γ-FeOOH,α-FeOOH and Fe3O4.