Trichrome passivates for treating galvanized steel

Abstract

In one embodiment, the invention provides a composition useful for passivating a metal surface, in particular a zinciferous surface, comprising, preferably consisting essentially of, most preferably consisting of water and: (A) dissolved phosphate ions; (B) dissolved trivalent chromium ions; (C) dissolved anions of at least one complex fluoride of an element selected from the group consisting of Ti, Zr, Hf, Si, Sn, Al, Ge and B; preferably Ti, Si and/or Zr; (D) an optional component of dissolved free fluoride ions; (E) organic acid inhibitor, preferably comprising quaternary ammonium compounds; and, optionally (F) a pH adjusting component; and optionally organic hydroxyl acids.

Dependencies are inferred from the claim text.