To achieve adhesion of the zinc-nickel alloy on a metal part, degreasing and pickling steps are carried out. DEGREASING: the objective is to eliminate the oils and greases that we have on the surface of the piece. PICKLING: in this stage the surface oxides adhered to the surface of the steel are eliminated by immersion in acid solutions, thus removing the scale from previous processes such as rolling.

En cualquier deposición electrolítica existe un flujo de electrones entre el ánodo del proceso, donde se producirá la oxidación del material y la pieza a recubrir donde tendrá lugar la reducción y con ello el recubrimiento de nuestra pieza con el metal que queremos. En el caso del cinc-níquel, el recubrimiento consiste en una aleación de cinc-níquel, con un contenido en níquel entre 12-16%. Este depósito se forma a partir de un sistema electrolítico alcalino libre de cianuros. El depósito sobre todas las superficies visibles será uniforme, siempre y cuando el metal base lo permita, adherente, libre de ampollas, picaduras y discontinuidades. In any electrolytic deposition there is a flow of electrons between the anode of the process, where the oxidation of the material will take place and the part to be coated where the reduction will take place and with it the coating of our part with the metal we want. In the case of zinc-nickel, the coating consists of a zinc-nickel alloy, with a nickel content between 12-16%. This deposit is formed from a cyanide-free alkaline electrolyte system. The deposit on all visible surfaces will be uniform, as long as the base metal allows it, adherent, free of blisters, pits and discontinuities.

When required, for parts with high hardness, specifically with tensile strength values ​​greater than 1000 MPa, it is necessary to heat the part to almost 200ºC after electrolytic deposition for a variable period of time depending on the hardness of the piece.

Passivation is the generation of a conversion coating that is applied to improve the corrosion resistance of the part and that modifies its appearance. After passivation, it is possible to subsequently apply a sealing stage, which penetrates the passivation, closing the micro-pores, increasing the white corrosion of the part.

The controls to represent coated pieces in a test will be inspected once these have been processed for their appearance with an amplitude of 10%, for their composition by X-ray spectrometry s / n ISO3497, thickness by X-ray spectrometry s / n ISO3497, adhesion , no flaking or blistering will occur after keeping them at 220 ± 10 ºC for 30 minutes with immediate immersion in water at 15-25ºC s / n ISO2819. This test is carried out on two selected samples and resistance to corrosion by saline mist tests s / n ISO9227.