Characterization of chromate conversion film on tinplate substrate by XPS and electrochemistry methods

The chromate conversion coating formed on commercial tinplate via a cathode electrolytic dichromate treatment has been studied by X-ray photoelectron spectroscopy (XPS) and electrochemistry methods. Through the analysis of the XPS, it was shown that there existed Cr, O, and Sn in the chromate coating and the chromate film consisted mainly of Cr(OH)(3), Cr(2)O(3), Sn, and SnO(x). The current density decreased with increasing of the electric charge. The corrosion resistance for tinplate is relative with the content of chromium in the passivation film. Copyright (C) 2009 John Wiley & Sons, Ltd.