稀土铈盐、镧盐钝化镀锌钢板表面性能对比

Performance Comparision of Passivation Films on Galvanized Steel Treated with Rare-earth Cerium and Lanthanum Salts

运用正交试验分别对稀土铈盐和镧盐钝化进行试验,得出该两种稀土盐钝化镀锌钢板的最优参数和工艺条件。醋酸铅点滴试验、盐雾试验、失重试验和电化学交流阻抗谱(EIS)测定表明,镧盐转化膜的耐蚀性优于铈盐转化膜,接近常规铬酸盐转化膜。扫描电镜(SEM)表明,镧盐转化膜明显比铈盐转化膜成膜致密,对基体覆盖度更高,且膜层相对较厚。XRD分析显示,铈盐成膜物质主要是CeO2,镧盐主要是La2O3。漆膜划格试验表明,镧盐转化膜附着力优于铈盐转化膜,达到5B标准,再涂装性能可靠。

The optimal processing parameters and conditions of passivation films on galvanized steel sheet treated with rare-earth cerium and lanthanum salts were obtained by orthogonal experimental method. The lead acetate test, salt spray test, weight loss test, EIS, SEM and XRD etc. were used to analyze the performance of passivation films. The results showed that the corrosion resistance of lanthanum film was better than that of cerium film, and the former was more close to the conventional chromate conversion coating. The lanthanum film was more dense and thicker, and had higher coverage on the matrix than cerium film. XRD analysis showed that the main filming materials of cerium salt and lanthanum salt was La2O3 and CeO2 respectively. The adhesion of lanthanum film reached 5B and was better than that of cerium film.