Polyacrylic Acid-Modified Zinc Phosphate Conversion Coatings for Corrosion Protection of Steel.

摘要

Polyacrylic acid, p(AA), electrolyte macromolecules diffused into crystalline zinc phosphate (Zn(center dot)Ph) conversion coatings that are precipitated onto cold-rolled steel by dissolution- recrystallization processes, enhance the corrosion protection of steel. One of the specific subserviences was that, when the NaOH- dissolution of Zn(center dot)Ph is considered, the Zn-OOC electrostatic bonds at p(AA)-Zn(center dot)Ph interfaces are transformed into Na(+)OOC ionic bonds which associate with the salt complexed macromolecules. Another is the intermolecular chemical reactions between p(AA) and polymeric topcoats. These contributions relate directly to a lower cathodic delamination rate. 9 refs., 6 figs., 2 tabs.