镁合金微弧氧化陶瓷膜耐蚀性的无损评价  

Lossless evaluation of corrosion resistance for micro-arc oxidation ceramic coating on magnesium alloy

作　　者：杨巍[1] 时惠英[1] 蒋百灵[1] 李均明[1] 

机构地区：[1]西安理工大学材料科学与工程学院,陕西西安710048

出　　处：《金属热处理》2009年第10期30-33,共4页Heat Treatment of Metals

基　　金：国家"十一五"科技攻关计划项目(2006BAE04B05-1)

摘　　要：在硅酸盐系电解液中,采用恒压模式制备具有相同厚度的微弧氧化陶瓷膜,借用扫描电镜观察陶瓷膜表面形貌,利用腐蚀面积法评价其腐蚀速率,使用LCR数字电桥测量陶瓷膜的介质损耗正切值tanδ,分析了微弧氧化能量参数对陶瓷膜表面微观形貌的影响,研究了介质损耗正切的平均值tanδ与陶瓷膜表面形貌的对应关系,探讨了以tanδ评价陶瓷膜耐蚀性的理论可行性。结果表明,随频率升高、占空比降低,陶瓷膜表面微孔孔径减小,致密性增大;tanδ随频率减小而线性增大,随占空比的增加而先平缓增加后急剧增大,随tanδ的增大陶瓷膜耐蚀性变差,可以用tanδ对陶瓷膜耐蚀性进行无损评价。Ceramic coatings with the same thickness were prepared on magnesium alloy in the silicate solution under the constant voltage mode. The surface morphologies of ceramic coatings were observed by SEM. The corrosion rates of the coatings were evaluated by the method of corrosion proportion. The value of medium ullage tangent tanδ was measured by LCR-digital electric bridge. The effects of micro-arc oxidation energy parameters on the surface morphologies of ceramic coatings were analyzed. Corresponding relations between the average value medimn ullage tangent tanδ and surface morphologies were investigated. Furthermore, the dependence of the corrosion resistance of ceramic coatings on the value of tanδ was discussed. The results show that micropore apertures of the surface of ceramic coatings are decreased and the compactness is increased with increasing the frequency or decreasing the duty cycle;tanδ is increased linearly with decreasing the frequency and increasing the duty cycle. The corrosion resistance of ceramic coatings gets worse with increasing tanδ As a result, the corrosion resistance of ceramic coatings evaluated lossless by tanδ is realized.

关 键 词：镁合金 陶瓷膜 介质损耗正切值 耐蚀性 无损评价 

分 类 号：TG146.2[一般工业技术—材料科学与工程]