不同封闭工艺对2195铝锂合金环保型阳极氧化膜耐蚀性能影响  

Effects of Different Sealing Processes on Anti-corrosion Properties of Environmentally-Friendly Anodic Oxidation Films on 2195 Al-Li Alloy

作　　者：陈妍 肖金涛 邢明秀 鞠鹏飞 周宏 夏云锋 于美 刘建华 CHEN Yan;XIAO Jintao;XING Mingxiu;JU Pengfei;ZHOU Hong;XIA Yunfeng;YU Mei;LIU Jianhua(Shanghai Aerospace Equipments Manufacturer Co.,Ltd.,Shanghai 200245,China;Key Laboratory of Aerospace Materials and Performance of Ministry of Education,School of Materials Science and Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]上海航天设备制造总厂有限公司,上海200245 [2]北京航空航天大学材料科学与工程学院空天先进材料与服役教育部重点实验室,北京100191

出　　处：《上海航天（中英文）》2020年第3期61-67,共7页Aerospace Shanghai（Chinese&English）

基　　金：国家自然科学基金资助项目(51771122);上海市浦江人才计划资助项目(19PJ1431500)。

摘　　要：针对轻量化航天装备的可靠性服役对2195铝锂合金提出的高耐蚀性需求,采用环保型硫酸己二酸(50 g/L硫酸和10 g/L己二酸)溶液体系在2195铝锂合金表面制备阳极氧化膜,对所得的膜层通过沸水封闭、铬酸盐封闭、镍盐封闭和铈盐封闭4种封闭工艺进行后处理,并利用扫描电子显微镜、动电位极化曲线、电化学阻抗谱等方法对膜层表面的显微形貌和耐蚀性能进行表征。结果表明:相较于未封闭的阳极氧化膜,4种封闭工艺均提高了膜层的耐蚀性能,其中镍盐封闭后对基体的钝化效果最好,铬酸盐封闭次之,沸水封闭和铈盐封闭对膜层防腐性能提升有限。对电化学阻抗谱的进一步解析表明,4种膜层阻挡层电阻Rb均在105Ω·cm^2数量级,膜层耐蚀能力主要来自于被水合及沉淀物充分填充的多孔层内部,相应的电阻Rp2的数值大小依次为镍盐封闭>铬酸盐封闭>沸水封闭≈铈盐封闭。In order to meet the high anti-corrosion requirements of 2195 Al-Li alloy for the reliable service of lightweight aerospace equipment,an environmentally-friendly sulphate hexanedioic acid(50 g/L sulfuric acid and 10 g/L hexanedioic acid)solution system is adopted to prepare anodic oxidation films on the surface of 2195 Al-Li alloy.The obtained films are treated by four sealing processes,i.e.,boiling water sealing,chromium salt sealing,nickel salt sealing,and cerium salt sealing.The surface microstructure is characterized by scanning electron microscope images,and the anti-corrosion properties are characterized by potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS)data.The results indicate that,compared with the unsealed anodic oxidation film,the anti-corrosion properties of the films treated by the four sealing processes are all improved,in which the passivation effect of nickel salt sealing on the matrix is the best,the passivation effect of chromium salt sealing is the second,and the effects of boiling water sealing and cerium salt sealing are limited.A further analysis of the EIS results indicates that the values of the barrier layer resistances Rb of the four sealed films are all of the order of 105Ω·cm^2.The anti-corrosion capability mainly comes from the inner part of the porous layer fully filled with hydrated substances and sediments.The values of the corresponding resistances Rp2 follow the sequence as follows:nickel salt sealing>chromium salt sealing>boiling water sealing≈cerium salt sealing.

关 键 词：环保型阳极氧化 2195铝锂合金 耐腐蚀性能 封闭 动电位极化 电化学阻抗谱 

分 类 号：TG174.4[金属学及工艺—金属表面处理]