Macdermid Enthone Gmbh

Enthone Incorporated

Andreas Konigshofen

Ronny Kiefer

Maik Winkler

Ulrich Prinz

Danica Elbick

Markus Dahlhaus

The invention relates to a corrosion protection layer system for metal surfaces, said layer system comprising as the two top most layers: a) a discontinuous nickel-phosphorus layer and b) a chromium layer plated from a trivalent chromium electrolyte solution, as well as to a method of producing such a layer system. The inventive layer system is capable to combine the good corrosion resistance of the nickel-phosphorus layer against sodium chloride with the protective power of the chromium layer from the trivalent plating process against magnesium and calcium salts, especially without the need for any post-treatment.

Multicorrosion protection system for decorative parts with chrome finish

The invention relates to a method for the adjustment of the lightness L* of electrolytically deposited chromium-finishes on workpieces obtained by an electroplating bath comprising at least chromium(III)-ions and sulfur containing organic compounds, wherein the concentration of the sulfur containing organic compounds in the bath are adjusted by passing at least part of the bath composition through an activated carbon filter. Furthermore, the invention is directed to dark chrome coatings comprising a defined concentration gradient of deposited sulfur containing organic compounds.

Flexible color adjustment for dark Cr(III) platings

The invention relates to a corrosion protection layer system for metal surfaces, said layer system comprising as the two top most layers: a) a discontinuous nickel-phosphorus layer and b) a chromium layer plated from a trivalent chromium electrolyte solution, and method of producing such a corrosion protection layer system. The corrosion protection layer system provides corrosion resistance of the nickel-phosphorus layer against sodium chloride with the protection of the chromium layer produced from a trivalent process again magnesium salts, without the need for any post-treatment.

A process for treating the surface of a metal substrate comprising a constituent metal selected from the group consisting of Cr, Cu, Mn, Mo, Ag, Au, Pt, Pd, Rh, Pb, Sn, Ni, Zn, in some cases Fe, and alloys of these metals. An anodic potential is applied to the metal surface in an electrolytic circuit comprising the metal surface, a cathode, and an electrolytic solution that is in contact with the metal surface and in electrically conductive communication with the cathode. The electrolytic solution may contain an electrolyte comprising anions of phosphate, phosphonate, phosphite, phosphinate, nitrate, borate, silicate, molybdate, tungstate, carboxylate, oxalate and combinations thereof. The anion may comprise a polymer having a pendent moiety selected from the group consisting of phosphate, phosphonate, phosphite, phosphinate, sulfate, sulfonate, carboxylate and combinations thereof. The potential applied to the circuit is such that the substrate is anodically oxidized and reacts with the anion to form a composition that imparts an enhanced property to the metal surface. Preferably, the pH of the electrolytic solution is less than about 6.0, the potential applied is between about 0.5 and about 20 volts, and the current density is between about 0.01 and 2 amps/dmof the geometric surface area of metal in contact with the electrolytic solution and is controlled such that nascent cations of said constituent metal produced by anodic oxidation of said constituent metal react with said anions at the metal surface without significant formation of any oxide or hydroxide of said constituent metal.

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Leverkusen, Germany

Andreas Konigshofen