【摘要】 为了提高镁合金镧转化膜的耐腐蚀性能,通过容量法和电化学方法研究了预处理对镁合金AZ91D镧转化膜在5%NaCl溶液中腐蚀行为的影响。利用扫描电子显微镜(SEM)和能量色散谱仪(EDS)研究了膜层表面形貌及其组成,通过电极电位的跟踪测试研究了镧转化膜的成膜过程。结果表明:预处理不改变镧转化成膜过程的基本规律,但有助于镧的氧化物沉积;提高了镁合金镧转化膜的耐腐蚀性能,浸泡30 h其耐腐蚀性能与传统的封闭的铬酸盐转化膜相当。更多还原

【Abstract】 Influence of pretreatment on rare earth(lanthanum) conversion coating and corrosion resistance of magnesium alloy AZ91D was investigated for improving its corrosion resistance.The corrosion resistance of magnesium alloy in 5% NaCl solution was studied by evolving hydrogen gas measurement and electrochemical tests.The surface morphologies and composition of lanthanum conversion coating were studied by means of scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS).Open circuit potential(OCP) of magnesium alloy with different treatment was tested in the formation process of lanthanum conversion coating.The results showed that pretreatment was helpful for deposition of lanthanum oxide and corrosion resistance was improved.During immersion in 5% NaCl solution for 30 h, corrosion resistance of lanthanum conversion coating with pretreatment was comparable with that of chromate conversion coating.更多还原