Multicorrosion protection system for decorative parts with chrome finish
AssigneeMacDermid Enthone Inc.
InventorsAndreas Konigshofen, Ronny Kiefer
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Abstract
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.
Claims14
A method for the production of a corrosion protection layer system on metal surfaces, said method comprising the steps of:
- a) providing a surface to be protected by a corrosion protection layer system,
- b) plating on said surface a-discontinuous nickel-phosphorus layer comprising inorganic solids by an electroplating process from a nickel electrolyte solution, wherein the discontinuous nickel-phosphorus layer comprises micropores and/or microcracks between 100 and 1,000,000 micropores per cm2 and/or between 10 and 10,000 microcracks per cm, and wherein the nickel-phosphorus layer comprises phosphorus in an amount between 2.0 wt. % and 20.0 wt. %, wherein the total weight of the nickel-phosphorus layer is 100 wt. %;
- and
- c) plating on said layer of step b) a chromium layer rom a trivalent chromium electrolyte solution by an electroplating process.
Dependencies are inferred from the claim text.