2024铝合金表面三价稀土转化膜

来源期刊：中国有色金属学报1999年第1期

论文作者：于兴文 周德瑞 尹钟大 周育红

文章页码：73 - 78

关键词：稀土转化膜，耐蚀性，微观形态，成膜机理，耐蚀机理

Key words：REM conversion coating, anticorrosive property, microstructure, mechanism of formation, mechanism of corrosion resistance

摘    要：利用浸渍法在2024铝合金表面上获得了金黄色的稀土转化膜， 确定了成膜的最佳工艺条件。 利用湿热试验、 盐水浸渍试验等实验方法评价了膜的耐蚀性能， 并和传统的MBV法及Alodine法进行了比较。 结果表明， 稀土转化膜的耐蚀性能优于MBV转化膜， 与Alodine转化膜接近。 利用电化学方法研究了稀土转化膜的耐蚀机理， 膜的存在同时抑制了腐蚀过程中的阴极反应和阳极反应，使腐蚀的动力消失。 利用扫描电镜观察了膜的微观形态， 膜是由大小不同的球状颗粒组成， 大的颗粒之上夹杂或附着小的颗粒， 膜的形成包含一个晶粒的形成和长大的过程。 稀土转化膜处理工艺简单，对环境无污染， 膜的耐蚀性强， 具有一定的应用前景。

Abstract: A golden conversion film was obtained on the surface of aluminum alloy 2024 by immersion process. The suitable conditions of technology were established. The anticorrosive property of the conversion film was examined intensively by moisture/heating test, salt solution immersion test. Compared with otherconversion coatings, the anticorrosive property of REM conversion coating is significantly superior to that of MBV conversion film and similar to that of anodizing coating. The mechanism of corrosion resistance of the film was studied by electrochemical method. The result showed that both anodic and cathodic reaction of corrosion were reduced by the exisiting film, thus the motivation of corrosion was decreased. The microphotography of the film was studied by scanning electron microscopy, which show that the film consists of different size of spherical particles,the bigger particles are dotted with smaller ones. The formation of the film consists of two steps: the formation and growth of the particles. This protection scheme is very simple, nontoxic, the film pocesses high anticorrosive property, the result is very encouraging.