3种硅氧烷不同pH值水解液封孔微弧氧化涂层的结构及耐蚀性能研究  

Study on the Structure and Corrosion Resistance of Sealing Micro-Are Oxidation Coatings of Three Types of Siloxanes in Hydrolytic Solutions at Different pH Values

作　　者：严涵 崔学军 齐玉明 曾山山 陈星佑 任清川 YAN Han;CUI Xuejun;QI Yuming;ZENG Shanshan;CHEN Xingyou;REN Qingchuan(School of Materials Seienee and Engineering,Sichuan University of Seience and Engineering,Zigong 643000,China;Sichuan Jiuzhou Elecric Group Co.,Ltd.,Mianyang 621000,China)

机构地区：[1]四川轻化工大学材料科学与工程学院,四川自贡643000 [2]四川九洲电器集团有限公司,四川绵阳621000

出　　处：《材料保护》2024年第9期117-124,160,共9页Materials Protection

基　　金：国家自然科学基金(52375196);四川省自然科学基金(2022NSFSC0330);四川轻化工大学研究生创新基金项目(Y2022007);大学生创新创业训练计划项目(S20221062202)资助。

摘　　要：为进一步增强微弧氧化涂层对镁合金的腐蚀防护能力,研究了3种硅氧烷水解液pH值对AZ31B镁合金表面微弧氧化/硅氧烷复合涂层表面结构及耐蚀性能的影响规律。通过恒压方法在硅酸盐电解液体系中制备微弧氧化涂层,随后调节硅氧烷水解液的pH值,通过浸渍的方法在微弧氧化涂层表面形成硅氧烷涂层。采用扫描电子显微镜(SEM)、Image-J图像分析法、测厚仪、表面粗糙度仪、接触角测试仪和电化学工作站研究了涂层表面的微观形貌、孔隙率、厚度、粗糙度、疏水性以及耐蚀性能。结果表明:与微弧氧化涂层相比,微弧氧化/硅氧烷复合涂层显著修复了微弧氧化涂层表面的微孔与缺陷,并赋予了涂层疏水性,能够有效阻止或减缓腐蚀介质的渗入,提高了涂层的耐蚀性能。对比3种硅氧烷,pH值为6的KH-570水解液制备的复合涂层的孔隙率最低,水接触角达到(126.5±2.3)°,自腐蚀电流密度为3.647×10^(-8)A/cm^(2),其耐蚀性能最好。To further enhance the corrosion protection capability of micro-arc oxidation(MAO)coatings on magnesium alloys,the effects of three different pH values of siloxane hydrolysis solutions on the surface structure and corrosion resistance of MAO/siloxane composite coatings on surface of AZ31B magnesium alloy were investigated.MAO coatings were prepared in a silicate electrolyte system using a constant pressure method.Subsequently,the pH values of the siloxane hydrolysis solutions were adjusted,and siloxane coatings were formed on the MAO coat-ings by immersion.The micro-morphology,porosity,thickness,roughness,hydrophobicity and corrosion resistance of the coatings were studied using scanning electron microscopy(SEM),Image-J image analysis,thickness gauge,surface roughness tester,contact angle goniometer and electrochemical workstation.Results showed that compared to micro-arc oxidation coatings,the MAO/siloxane coatings significantly repaired the micropores and defects on the surface of the micro-arc oxidation coatings.The MAO/siloxane coatings also imparted hydrophobic proper-ties,effectively preventing or slowing down the penetration of corrosive media and enhancing the corrosion resistance of the coatings.Among the three siloxanes compared,the composite coating prepared from KH-570 hydrolysate with a pH of 6 exhibited the lowest porosity,a water con-tact angle of(126.5±2.3)°,and a self-corrosion current density of 3.647×10^(-8)A/cm^(2),demonstrating the best corrosion resistance.

关 键 词：镁合金 微弧氧化 硅氧烷 pH值 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]