Corrosion performance of a two-step pre-treatment for galvanized steel based on lanthanum nitrate and silanes

摘要

The present work investigates a two-step pre-treatment for coil-coated galvanized steel based on the use of La(NO3)(3) and silanes. The pre-treated surfaces were characterized by Auger spectroscopy and XPS. The analytical results give the chemical composition of the films. The work discusses the role of the functional group (sulfur) present in one of the silanes on the formation of the surface film. Corrosion resistance was assessed by electrochemical impedance spectroscopy and the results show that the pre-treatment improves the corrosion resistance of the uncoated and coated substrates. Copyright (C) 2004 John Wiley Sons, Ltd.