Evaluation of the corrosion resistance of different galvanized steels treated in a cerium salt solution

摘要

Analysis of polarization curves and impedance spectra has shown that the surface chemistry of galvanized steels plays an important role in determining their corrosion behavior. Zn-Ni samples that were untreated or had been treated in a 10 mM Ce(NO{sub}3){sub}3 solution had the lowest corrosion rates in 0.5 N NaCl. The efficiency of the surface modification process was the highest for electrogalva-nized steel. Surface analysis showed that the protective layers on Zn-Ni and electrogalvanized steel contained mainly cerium oxides/hydroxides, while the layer on hot-dipped steel consisted mainly of zinc hydroxide.