The corrosion performance of organosilane based pre-treatments for coatings on galvanised steel

摘要

The work aims at the search of environmentally friendly pre-treatment technologies for improved coating adhesion and corrosion resistance of coil coatings. Hot-dip galvanised steel panels were treated with a zirconium nitrate/organosilane solution. Three different treatments based on organofunctional silanes were investigated. The analytical characterisation of the substrates was made by Auger electron spectroscopy and X-ray photoelectron spectroscopy. The corrosion behaviour of the painted systems under immersion in sodium chloride solution was investigated by means of electrochemical impedance spectroscopy. The corrosion resistance of the painted panels is interpreted based on the nature of the organosilane used in the pre-treatment and on its distribution over the substrate.