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.

Abstract: The present invention relates to a chrome free etch for plating on plastic processes, wherein plastic surfaces are contacted in a first etching step with an etching solution at least comprising Mn(IV)-ions and, in a second etching step, with a solution at least comprising Mn(III)- and Mn(VII)-ions prior to the metal plating step.

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, 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.