Abstract
ABSTRACT
Zinc and zinc coated products corrode in ambient air and in the presence of water rapidly, producing a white corrosion product – named as white rust. Chromate conversion coatings provide very effective corrosion protection against white rust. Due to the toxic and carcinogenic properties of Cr6+ ion, the corrosion protection with chromating technique needs replacement. The objective of our studies was to protect zinc surface against corrosion, with a thin phosphonate layer. For surface pre-treatment, aqueous solutions of diphosphonic acid with different alkyl-chain length were applied with different treatment times. The spontaneously formed 1,5-diphosphono-pentane layer on zinc surface has protective effect in corrosive environment.