室温下AZ91镁合金Ce-Mn化学转化液配方的优化  

Composition Optimization of Room Temperature Cerium-Manganese Chemical Conversion Fluid for AZ91 Magnesium Alloy

作　　者：盘艳红[1] 杜军[1] 李文芳[1] 穆松林[1] 黄筑艳[2] 

机构地区：[1]华南理工大学材料科学与工程学院,广东广州510640 [2]贵州大学化学工程学院,贵州贵阳550003

出　　处：《材料保护》2012年第9期43-45,64,共4页Materials Protection

基　　金：粤港关键领域重点突破(佛山专项)专项基金(2008Z012);广东省重大科技专项(产业共性技术)基金(2009A08025002)资助

摘　　要：为了进一步探明镁合金Ce-Mn化学转化液添加四硼酸钠后各组分的最佳含量,采用正交试验从膜自腐蚀电流和钝化区间角度优化了以Ce(NO3)3为主盐、KMnO4为氧化剂、四硼酸钠为添加剂的镁合金Ce-Mn转化膜的成膜液组分。用极化曲线研究转化膜的耐腐蚀性能,并用扫描电镜(SEM)及能谱仪(EDS)对转化膜的微观形貌和成分进行分析。结果表明:最佳成膜液配方为5～8 g/L Ce(NO3)3,1.6～2.0 g/L KMnO4,0.2～0.5 g/L四硼酸钠;镁合金经该成膜液处理后表面形成均匀的转化膜,自腐蚀电位正移、自腐蚀电流密度降低,对镁合金起到了良好的防护作用。The composition of Ce-Mn chemical conversion bath for room temperature chemical conversion treatment of AZ91 magnesium alloy was optimized in relation to corrosion potential of the conversion coating and passivation range by orthogonal test,where Ce(NO3)3 was used as the major salt,KMnO4 as the oxidant,and Na2B4O7·10H2O as the additive.The optimized content of various ingredients in the chemical conversion bath was determined.The polarization curve of Ce-Mn conversion coating was measured,and its corrosion resistance was evaluated accordingly.Moreover,the morphology and elemental composition of Ce-Mn conversion coating on Mg alloy were analyzed by means of scanning electron microscopy and energy dispersive spectrometry.Results show that the conversion bath has an optimal composition of 5～8 g/L Ce(NO3)3,1.6～2.0 g/L KMnO4,and 0.2～0.5 g/L Na2B4O7·10H2O.Homogeneous Ce-Mn chemical conversion coating can be formed on the surface of Mg alloy after chemical conversion treatment in the optimized bath.As-prepared Ce-Mn conversion coating can increase the corrosion potential and obviously decrease the corrosion current density of AZ91 Mg alloy,showing good protective effect for AZ91 Mg alloy.

关 键 词：Ce—Mn转化膜 镁合金 配方 正交优化 耐蚀性 

分 类 号：TG174.44[金属学及工艺—金属表面处理]