摘要
为进一步增强微弧氧化(MAO)处理后镁合金的耐蚀性能,通过涂装聚苯胺改性环氧树脂(PMER)制备了MAO/PMER复合涂层,并利用扫描电子显微镜(SEM)、电化学工作站、中性盐雾试验箱等表征手段研究了涂层的结构、耐蚀性能及其长期腐蚀行为。结果表明:MAO涂层样品在盐雾试验第5 d时已经出现明显的腐蚀条纹,而复合涂层样品在至少15 d后才发生明显的鼓泡现象;与MAO涂层样品相比,复合涂层样品的腐蚀电流密度下降了3个数量级,极化电阻提高了2个数量级,PMER涂层显著提高了MAO涂层对镁合金基体的腐蚀防护能力,并且随着PMER涂层厚度从40μm增加到110μm,复合涂层的腐蚀防护能力变得更佳。在30天的中性盐雾腐蚀过程中,复合涂层样品的阻抗值在109~1010Ω·cm2内波动,而MAO样品在10 d后阻抗值降低至200Ω·cm2左右。MAO涂层易受氯离子破坏而导致涂层失效,而PMER涂层不仅起到优异的物理屏障作用,还具有低一定的缓蚀及自修复能力,这将能有效地提高对镁合金MAO的后长效防腐寿命。
To further improve the corrosion resistance performance of micro-arc oxidation(MAO)coated magnesium alloys,the MAO/polyaniline modified epoxy resin(PMER)composite coatings was fabricated.The structure of the composite coating was investigated by scanning electron microscope(SEM),their long-term corrosion behavior and corrosion resistance perform-ance were studied by electrochemical workstation and neutral salt spray test chamber.The results show that the MAO coated sam-ples appear corrosion stripe on the 5 th day of the salt spray test,while the composite coated samples appear obvious bubble until the 15 th day later.Compared with the MAO coated samples,the corrosion current density of the composite coated samples decrease by about three orders of magnitude,and the polarization resistance increase by about two orders of magnitude.It indicats that the PMER layer significantly improved the corrosion protection ability of MAO coatings to the AZ31 B magnesium alloy,and the corrosion protection ability of composite coatings become better with the increase of thickness of PMER layer from 40 to 110μm.In 30 days of neutral salt spray corrosion process,the impedance value of the composite coated samples fluctuates in the range of 109-1010Ω·cm2,while MAO coated samples only remaines around 200Ω·cm2 after 10 days of salt spray corrosion.MAO coatings are easily damaged by chloride ion,which will fail to protect AZ31 B magnesium alloy.The PMER layer not only has excellent physical barrier effect,but also has excellent corrosion inhibition and self-repair ability,which can effectively increase the long-term anticorrosion life of magnesium alloy after MAO process.
作者
莫格
崔学军
张颖君
李明田
宁闯明
MO Ge;CUI Xuejun;ZHANG Yingjun;LI Mingtian;NING Chuangming(School of Materials Science and Engineering,Sichuan University of Science and Engineering,Zigong 643000,China;Key Laboratories of Fine Chemicals and Surfactants in Sichuan Provincial Universities,Sichuan University of Science and Engineering,Zigong 643000,China)
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2020年第2期37-46,共10页
China Surface Engineering
基金
中央引导地方科技发展专项(20208Y0053)
精细化工助剂及表面活性剂四川省高校重点实验室开放基金(2020JXY05)
国家自然科学基金(51801131)
关键词
镁合金
微弧氧化
改性环氧树脂
聚苯胺
腐蚀行为
magnesium alloy
micro-arc oxidation
modified epoxy resin
polyaniline
corrosion behavior
