镁合金表面PEF膜与PEO膜腐蚀防护行为的对比研究  

Comparison of Corrosion Behaviour of PEF and PEO Coatings on Mg Alloys

作　　者：齐玉明 刘思勤 罗兰 彭振军[1] 梁军[1,2] 王鹏 QI Yu-ming;LIU Si-qin;LUO Lan;PENG Zhen-jun;LIANG Jun;WANG Peng(State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院兰州化学物理研究所固体润滑国家重点实验室,兰州730000 [2]中国科学院大学材料与光电研究中心,北京100049

出　　处：《表面技术》2021年第6期41-54,147,共15页Surface Technology

基　　金：国家自然科学基金(52071325)。

摘　　要：目的对比研究镁合金表面新型等离子体电解氟化(PEF)膜与传统等离子体电解氧化(PEO)膜的腐蚀防护行为。方法分别在中性和酸性腐蚀介质中,通过开路电位监测和动态电位极化曲线测试表征了膜层的电化学腐蚀行为,通过浸泡实验和盐雾实验表征了膜层的长效腐蚀行为。通过SEM、EDS和XRD等方法表征了膜层的原始微观结构和组成,分析了腐蚀形貌和腐蚀产物。结果 PEF膜与PEO膜均可以为镁合金基材提供有效的腐蚀防护作用。相较于PEO膜,PEF膜在浸泡实验和盐雾实验中,都具有更为优异的腐蚀防护性能,但在动态电位极化测试中,具有更正的自腐蚀电位和更大的自腐蚀电流密度,表明其腐蚀倾向更低,但腐蚀速率更高。结论总体而言,PEF膜在中性和酸性环境中都具有更好的腐蚀防护性能。PEO膜在中性环境中的腐蚀防护失效机制主要是腐蚀介质的扩散,在酸性环境中的腐蚀防护失效机制主要是膜层化合物的溶解和消耗;PEF膜在中性和酸性环境中的腐蚀防护失效机制都是腐蚀介质的扩散。The work aims to compare the novel PEF coating and conventional PEO coating in terms of corrosion behavior.The electrochemical corrosion behavior was evaluated by means of OCP monitoring and potentiodynamic polarization tests in neutral and acidic corrosive media,while the long-term corrosion behavior by immersion and salt spraying tests.SEM,EDS and XRD were employed to characterize the coatings’original microstructure and composition,as well as the characteristics of the corroded coatings and resultant corrosion products.The results show that the PEF coating was effective to protect Mg alloys from corrosion damage as well as the PEO coating.The PEF coating was performed better than the PEO coating in corrosion resistance during the immersion and salt spraying tests,but showed a higher corrosion potential and corrosion current density which respectively indicated a lower corrosion tendency and a higher corrosion rate.In sum,the PEF coating was performed better than the PEO coating in corrosion resistance.The corrosion failure of the PEF coating was mainly attributed to the diffusion of the neutral corrosive medium or the dissolution of the coating in acidic corrosive medium.The corrosion failure of the PEF coating was attributed to the diffusion of the corrosive media.

关 键 词：镁合金 等离子体电解氟化 等离子体电解氧化 腐蚀防护行为 

分 类 号：TG174.4[金属学及工艺—金属表面处理]