不同表面状态镀锡钢板铬酸盐钝化膜中铬元素的XPS分析

XPS Analysis of Chromium Element in Chromate Passivation Film Formed on Tinplate in Different Surface State

用X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)分析的方法,对铬酸盐钝化镀锡钢板的正常表面及缺陷点处铬元素的含量、价态以及由铬元素组成的化合物进行了研究。用超声波的方法对铬酸盐钝化镀锡钢板进行处理后,研究了超声波处理对缺陷处的铬元素的含量、价态的影响。结果表明,钝化膜中主要含有Cr,O,Sn元素。镀锡铬酸盐钝化膜中正常表面的铬元素主要是以Cr(OH)3,Cr单质以及Cr2O3的形态存在。在对镀锡板表面进行阴极电解钝化的过程中,Cr(Ⅵ)发生了转化,价态降低。在缺陷处,除了有Cr(OH)3和Cr2O3以外,还有微量的Cr(Ⅵ)存在。在缺陷处铬元素的含量低于正常表面,在超声波清洗处理后,缺陷处铬元素的含量明显低于不经超声波清洗的含量。施加的超声波因产生强烈的洗脱作用,使吸附在缺陷处的微量的Cr(Ⅵ)消失。

X-ray photoelectron spectroscopy （XPS） was used to investigate the content and chemical valence of chromium element, and the content of compounds in chromate passive film formed on commercial tinplate via a cathodic electrolytical treatment. The effect of the content and chemical valence for different surface state was studied by using ultrasonic process. From the results, it was shown that there existed Cr, O and Sn in the passivation film. The chromium element in the film was mainly in the forms of Cr（OH）3, Cr2 O3, and Cr in the natural surface. The Cr（Ⅵ） changed to lower value in the process of cathodic electrolytical treatment. A small quantity of Cr（Ⅵ） was found in the defective surface besides Cr（OH）3 and Cr2O3. The content of chromium element in the defective surface was lower than that in the natural surface. When ultrasonic process was added, the content of chromium element in the defective surface was obviously lower than that when no ultrasonic process was added. When ultrasonic process was used, the small quantity of Cr（ Ⅵ ） originally adsorbed on the defective surface disappeared because of the strong elution produced by ultrasonic.