| abstract |
Substantially improved resistance to sea water corrosion along with adequate hydrophilicity and retention or even improvement of hydrophilicity after exposure to high temperature can be provided on a metal substrate, particularly an aluminum alloy of the type used for heat exchanger fins, by an aqueous liquid hydrophilicizing treatment compositions containing poly{alkylene imine} and alkali metal silicate, and, optionally, polyether polyols. The hydrophilicizing treatment is preferably applied over a conventional conversion coating, particularly a chromium phosphate or chromium oxide conversion coating. |