30CrMnSiA钢表面镉镀层化学转化膜的电化学特性_皮志超.pdf

第 52 卷 第 6 期 表面技术 2023 年 6 月 SURFACE TECHNOLOGY 307 收稿日期：20220426；修订日期：20221013 Received：2022-04-26；Revised：2022-10-13 基金项目：上海航翼高新技术发展研究院有限公司合作项目（1005KFA20890）Fund：Shanghai Hangyi Research Institute of High-tech Development Cooperation Fund(1005-KFA20890)作者简介：皮志超（1986），男，硕士。Biography：PI Zhi-chao(1986-),Male,Master.通讯作者：周飞（1969），男，博士，教授，主要研究方向为表面工程和锂离子电池相关技术。Corresponding author：ZHOU Fei(1969-),Male,Doctor,Professor,Research focus:surface engineering and Li-ion battery related technology.引文格式：皮志超,宋宜强,闫江涛,等.30CrMnSiA 钢表面镉镀层化学转化膜的电化学特性J.表面技术,2023,52(6):307-318.PI Zhi-chao,SONG Yi-qiang,YAN Jiang-tao,et al.Electrochemical Characteristics of Chemical Conversion Film of Cadmium Coating on 30CrMnSiA Steel SurfaceJ.Surface Technology,2023,52(6):307-318.30CrMnSiA 钢表面镉镀层化学 转化膜的电化学特性 皮志超1,2，宋宜强1，闫江涛1，李柱祥2，胡水莲2，周飞1（1.南京航空航天大学 航空航天结构力学及控制全国重点实验室，南京 210016；2.国营芜湖机械厂，安徽 芜湖 241007）摘要：目的目的 通过研究镉镀层绿色化学转化膜的电化学性能，获得镉镀层最佳绿色化学钝化工艺。方法方法 采用无氰镀镉工艺，在 30CrMnSiA 钢表面电镀镉。采用植酸和钼酸钠在镉镀层表面进行绿色钝化处理，构建复合化学转化膜。通过研究钼酸钠浓度、处理时间和植酸浓度对绿色钝化处理镀镉层在质量分数为 3.5%的NaCl 溶液中电化学性能的影响，获得最佳的镀镉层绿色钝化工艺。结果结果 在处理时间为 10 min、植酸的质量分数为 1.0%的条件下，当钼酸钠的质量分数增至 3%时，开路电压先从0.741 9 V 增至0.739 7 V 后，再降至0.761 1 V，电荷转移电阻 Rct从 2.34 kcm2增至 8.79 kcm2，腐蚀抑制率从 72.9%增至 92.8%，自腐蚀电流密度 Jcorr从 81.47 A/cm2降至最低值（6.887 2 A/cm2）。当钼酸钠和植酸的质量分数分别为 2.0%和1.0%时，随着处理时间的延长，开路电压从0.755 9 V 增至0.729 5 V，Rct先增至 6.68 kcm2，然后降至5.28 kcm2，自腐蚀电流密度从 16.26 A/cm2降至 4.527 A/cm2。当钼酸钠的质量分数为 2.0%、处理时间为 10 min 时，随着植酸浓度的增加，试样的开路电压从0.739 3 V 降至0.756 1 V，Rct先增至 6.68 kcm2，然后降低，自腐蚀电流密度 Jcorr呈现先降至最小值后再增大的趋势。结论结论 与镉镀层相比，经化学转化膜处理后试样表现为高的开路电压、大的电荷转移电阻和低的自腐蚀电流。得到了耐蚀性好且成本较低的镉镀层表面绿色钝化工艺，钼酸钠和植酸的质量分数分别为 2.0%和 1.0%，处理时间为 10 min。关键词：镉镀层；化学转化膜；腐蚀；电化学；阻抗；极化曲线 中图分类号：TQ153 文献标识码：A 文章编号：1001-3660(2023)06-0307-12 DOI：10.16490/ki.issn.1001-3660.2023.06.027 Electrochemical Characteristics of Chemical Conversion Film of Cadmium Coating on 30CrMnSiA Steel Surface PI Zhi-chao1,2,SONG Yi-qiang1,YAN Jiang-tao1,LI Zhu-xiang2,HU Shui-lian2,ZHOU Fei1(1.State Key Laboratory of Mechanics and Control for Aerospace Structures,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;2.State-owned Wuhu Machinery Factory,Anhui Wuhu 241007,China)308 表 面 技 术 2023 年 6 月 ABSTRACT:The work aims to obtain the best green chemical passivation process of cadmium plating layers by studying the electrochemical properties of green chemical conversion films of cadmium plating layers.The cadmium coatings were electroplated on the surface of 30CrMnSiA steel through the cyanide-free cadmium plating process,and the green passivation treatment was performed on the cadmium coating on the surface of 30CrMnSiA steel in the solution containing phytic acid and sodium molybdate,then a composite chemical conversion film was constructed on the surface of the cadmium layer.After the effects of sodium molybdate concentration,phytic acid concentration and treatment time on the electrochemical properties of the green passivation cadmium plating layer were studied in 3.5wt.%NaCl solution,the green chemical passivation process of cadmium plating layer was obtained.When the treatment time was 10 min and the concentration of phytic acid was 1.0wt.%,with an increase of 3%in the concentration of sodium molybdate,the open circuit voltage value of the sample first increased from 0.741 9 V to 0.739 7 V,and then decreased to 0.761 1 V.And the charge transfer resistance Rct value and corrosion inhibition rate also increased from 2.34 kcm2 to 8.79 kcm2 and 72.9%to 92.8%,respectively,while its self-corrosion current density Jcorr first decreased from 81.47 A/cm2 to 6.887 A/cm2.If the concentrations of sodium molybdate and phytic acid were 2.0wt.%and 1.0wt.%,respectively,with the increase of treatment time,the open circuit voltage value of the sample increased from 0.755 9 V to 0.729 5 V.Its Rct value first increased to 6.68 kcm2,and then decreased to 5.28 kcm2,while its self-corrosion current density decreased from 16.26 A/cm2 to 4.527 A/cm2.When the concentration of sodium molybdate was 2.0wt.%and the treatment time was 10 min,with the increase of phytic acid concentration,the open circuit voltage value of the sample decreased from 0.739 3 V to 0.756 1 V.And its Rct value first increased to 6.68 kcm2,and then decreased,while the self-corrosion current density Jcorr value first decreased to the minimum value and then increased.Compared with the cadmium coating,the samples treated with the chemical conversion coating have higher open circuit voltage,larger charge transfer resistance and lower self-corrosion current.The green passivation process for the surface of cadmium coating has good corrosion resistance and low cost concentration.The sodium molybdate and phytic acid are 2.0wt.%and 1.0wt.%,respectively,and the treatment time is 10 min.KEY WORDS:cadmium coating;chemical conversion film;corrosion;electrochemical;impedance;polarization curve 30CrMnSiA 钢是制造飞机发动机机架、机翼接头、起落架作动筒及螺栓紧固件等常用的高强度钢材，但它在海洋性大气环境中极易腐蚀，造成力学性能的退化1-2。镉镀层作为牺牲阳极性镀层，能够为30CrMnSiA 钢提供腐蚀防护。如果镉镀层表面不经后续的表面处理，就会很快地被腐蚀消耗，使得镉镀层达不到