| abstract |
A chromium-free conversion coating that optimizes the conversion process and conversion coating to further enhance corrosion protection without compromising adhesion. A composition comprising a conductive polymer dispersion, a silane, a zirconium salt, and a cerium nitrate salt, wherein the pH value is between 1.0 and 6.0. Preferably, the zirconium salt is potassium hexafluorozirconate, preferably the cerium nitrate salt is selected from cerium (III) nitrate, cerium (IV) ammonium nitrate, and any combination thereof, particularly preferably A composition, which is ceric (IV) ammonium nitrate. A) pretreating the metal surface; b) coating the metal surface with a conversion coating by contacting such metal surface with the composition; and c) drying the coated metal surface. A step of treating the metal surface. [Selection] Figure 1 |