钝化方式对镀锡板钝化膜组成与性能的影响

Effects of different passivation methods on composition and performances of the passivation film on tinplate

为提高镀锡板表面钝化膜的性能,利用X射线光电子能谱(XPS)、扫描Kelvin探针(SKP)、Tafel曲线和盐雾试验等方法,研究了化学钝化(300工艺)、电化学钝化(311工艺)与化学–电化学联合钝化(300+311和311+300工艺)4种不同钝化方式所得钝化膜的组成与耐蚀性能。结果表明,300工艺得到的钝化膜均匀性较好,311工艺得到的钝化膜铬含量较高、较厚、耐蚀性较强。联合钝化方式结合了300与311两种工艺的优点,所得钝化膜中铬氧化物的水合程度小,烘烤稳定性强。其中,300+311(先化学钝化后电化学钝化)工艺的钝化效果最好,钝化膜均匀性与耐蚀性最优。建议在镀锡板钝化生产中,第一个槽的第一道工序可以不通电以进行化学钝化,之后再电化学钝化。

In order to enhance the performance of the passivation film on surface of tinplate, the composition and properties of the passivation films obtained by four different passivation methods, including chemical passivation （300 treatment）, electrochemical passivation （311 treatment）, and chemical-electrochemical composite passivation methods （300 followed by 311 and 311 followed by 300 treatments） were studied by X-ray photoelectron energy spectroscopy （XPS）, scanning Kelvin probe （SKP） technique, Tafel curve measurement, and salt spray test. The results showed that the uniformity of the passivation film prepared by 300 treatment is better than that of the passivation film obtained by 311 treatment, while the chrome content, thickness, and corrosion resistance of the later are higher than that of the former. The united passivating methods combine the advantages of the 300 and 311 treatments, make the passivation films less hydrated for chromium oxide and higher stability in baking. The 300＋311 （chemical passivation followed by electrochemical passivation） treatment has the best passivation effectiveness due to the fact that the passivation films obtained thereby show the best uniformity and corrosion resistance. It is proposed that during tinplate passivation production, chemical passivation should be conducted during the first procedure in the first passivation tank, and then electrochemical passivation follows.