PASSIVATING ALKALINE COMPOSITION ON THE BASIS OF WATER GLASS

摘要

The present invention relates to an alkaline aqueous composition on the basis of water glass and organosilanes with non-hydrolysable substituents which have a primary amino group in the substituents, for providing corrosion-protected coatings on metal surfaces which convey good reshaping properties in metal processing. For the desired functionality, the compositions according to the invention contain the organosilane and the water glass in a predetermined ratio. The invention further relates to a method for pre-treating metal surfaces using the alkaline aqueous compositions, which method provides excellent results with regard to corrosion protection, varnish adhesion and reshapability, particularly on aluminium and on steel strips provided with aluminium alloy metal coatings.