IMPROVED CHROMIUM-FREE COMPOSITION AND PROCESS FOR CORROSION RESISTING TREATMENTS FOR ALUMINUM SURFACES

摘要

An exceptionally effective chromium free corrosion protective surface treatment composition for aluminum and its alloys is an aqueous acidic liquid comprising water and: (A) from about 0.8 to about 1.2 w/o of H2ZrF6; (B) from about 0.08 to about 0.12 w/o of dispersed silica; (C) from about 0.08 to about 0.12 w/o of a water soluble or dispersible polymer of 3-(N-methyl-N-2-hydroxyethylaminomethyl)-4-hydroxystyrene; and (D) from 0.10 - 0.15 w/o of 1-propoxy-2-propanol. The surface to be treated is contacted with the composition and then dried without rinsing. A conventional organic coating may advantageously be applied over the surface produced by this treatment.