AZ31镁合金稀土转化成膜工艺研究

Study of technology for rare earth conversion coating on AZ31 magnesium alloy

本文对AZ31镁合金表面稀土转化成膜工艺进行了研究。分析了不同的成膜工艺参数(稀土盐溶液组成、转化成膜时间)对稀土转化膜的形貌及耐蚀性能的影响。扫描电镜分析了不同成膜工艺形成的稀土转化膜的表面形貌;极化曲线研究了转化膜的电化学腐蚀行为。结果表明:当转化液中硝酸铈浓度为4.3423g·L-1和硝酸镧浓度为4.3302g·L-1时,转化膜的耐蚀性能最好;成膜时间对膜的耐蚀性也有不同程度的影响。

Technological process of rare earth conversion coating on AZ31 magnesium alloy was studied. The effects of various technical parameters, such as the composition of rare earth salts, conversion time on the morphologies and corrosion resistances of the coating were researched. Morphologies of the coatings were observed by SEM. The corrosion resistances of the coatings were studied by polarization curves. The results indicated that the optimized composition of the solution was 4.3423g· L^-1 Ce（NO3）3 and 4.3302g· L^-1 La（NO3）3. The immersion time also affected the corrosion resistance of coating.