镀锌钢板稀土铈盐钝化工艺

Rare Earth Cerium Passivation Technology of Galvanized Steel

采用单因素试验确定了稀土钝化镀锌钢板的最佳工艺条件:30 g·L^(-1)硝酸铈、20 mL·L^(-1)双氧水、pH值3.5、40℃下钝化60 s。利用碱浸失重试验、中性盐雾试验和电化学阻抗谱研究了钝化膜的耐蚀性能。结果表明,经稀土铈盐处理后的试样表面,其阻抗值相对于空白试样大幅度提高,腐蚀速率降低近1个数量级,抗白锈时间达46 h。扫描电镜(SEM)结果表明,稀土铈盐钝化膜对基体的覆盖度较高。

The technology of rare earth cerium conversion coating for galvanized steel was studied by a single factor experiment to get the optimized passivation parameters when the concentration of Ce（NOa ） was 30 g L-1 , H2O2 was 20 mL L-1 , pH= 3. 5 and passivated at 40℃ for 60s. The corrosion resistance was examined by weight loss test, neutral salt spray test and electrochemical impedance spectroscopy. The results showed that the corrosion impedance of the pretreated sample was significantly improved, the corrosion rate was decreased by one order of magnitude, and the anti-white rust time was 46h. Scanning electron microscopy （SEM） observation showed that the conversion coating covered the surface of zinc compactly.