NaCl溶液中20Cr9Ni5Co14不锈钢电化学腐蚀行为

发布时间：2018-02-23 21:10

本文关键词： 电化学极化交流阻抗 CrNiCo 不锈钢　出处：《东北大学学报(自然科学版)》2015年06期 　论文类型：期刊论文

【摘要】：采用电化学极化技术(动电位极化技术、线性极化技术和循环极化技术)和交流阻抗技术研究了不同条件下20Cr9Ni5Co14超高强度不锈钢的电化学腐蚀行为,并采用扫描电镜对极化后腐蚀形貌进行了表征.结果表明,20Cr9Ni5Co14钢在3.5%(质量分数)Na Cl溶液中出现钝化.随着Na Cl浓度的升高,钝化现象消失,而自腐蚀电流密度从8.223×10-7A/cm2减小至1.129×10-7A/cm2;随着p H值的降低,20Cr9Ni5Co14钢的致钝电位和过钝化电位增加.在p H值高于3时,腐蚀产物膜具有良好的耐腐蚀性能而导致反应步骤成为控制步骤.而当p H值降低到2时,腐蚀产物溶解速度很快,金属界面发生腐蚀速率很大,浓差极化成为了控制步骤.对腐蚀形貌研究表明,20Cr9Ni5Co14钢在极化过程中出现点腐蚀,导致了材料的耐腐蚀性能下降.
[Abstract]:Electrochemical corrosion behavior of 20Cr9Ni5Co14 ultrahigh strength stainless steel under different conditions was studied by electrochemical polarization (potentiodynamic polarization, linear polarization and cyclic polarization) and AC impedance technique. The corrosion morphology after polarization was characterized by scanning electron microscope. The results showed that the passivation occurred in 3.5% (mass fraction) NaCl solution. With the increase of NaCl concentration, the passivation phenomenon disappeared. However, the corrosion current density decreased from 8.223 脳 10 ~ (-7) A / cm ~ (2) to 1.129 脳 10 ~ (-7) A / cm ~ (2). With the decrease of pH value, the obtuse potential and over-passivation potential of 20Cr9Ni5Co14 steel increased. The corrosion product film has good corrosion resistance, which leads to the reaction step becoming the control step, but when the pH value is reduced to 2:00, the dissolution rate of corrosion product is very fast, and the corrosion rate of metal interface is very high. The corrosion morphology of 20Cr9Ni5Co14 steel was studied. It was found that the corrosion resistance of steel 20Cr9Ni5Co14 decreased as a result of the pitting corrosion during the polarization process.
【作者单位】：北京航空航天大学材料科学与工程学院;沈阳飞机设计研究院;中国人民解放军驻沈阳飞机工业(集团)有限公司军事代表室;
【基金】：国家自然科学基金资助项目(51171011)
【分类号】：TG172;TG142.71

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