Electroless Nickel Plating is a process of applying metallic coating to other metals or non-conductive substrates like plastic without the use of electric current. This is an auto catalytic, chemical bathing method from small to large nickel plating that has developed to be very benefiting for the manufacturing industry. The process happens through a controlled chemical reduction that is catalyzed by a metal or an alloy. Optimum quality is reached dependent on the success of maximum and uniform coating adhesion to the material. Electroless nickel plating has a lot of advantages such as: being free from flux-density, electric power issues, consistent plating and it prevents wear as well as corrosion. Moreover, even if the substrate structure is of complicated geometrical form, electroless nickel plating can still deliver a seamless finish to the plated product. Large nickel plating is one of the toughest yet achievable challenges of this technology. With time, bigger structures have been featured to be successfully plated by the process.
Historically, the plating of metallic nickel from a liquid chemical using hydrophosphite as the catalyst was first noted in the 1800s and it started to be developed during the 1940s at the time of the World War II. This technology had its full bloom in 1981 when it became industrialized to be the better option over electroplating. The other advantages of this technique are no sophisticated jigs required, flexibility in plating volume and thickness, complex filtration method is not required and matte, semi-bright or bright finishes can be achieved. There is a bit of challenge on the chemicals used since their shelf life are short, hence waste treatment is very costly. Aside from that, ENP is just the best option for small or large scale nickel plating. Some good examples of products are doorknobs, kitchen utensils, bathroom fixtures, office equipment as well as electric and mechanical tools. Also, since the coating is so strong it can be used to save corroding and worn parts of materials as well. Lastly, electroless nickel plating is also extensively used in the manufacture of hard disk drives, the layers of coating protect the magnetic layer should R/W head lose its air cushion and make contact with surface.
The process begins with pre-treatment wherein the material to be coated is thoroughly cleaned in series using different kinds of chemicals and most importantly water. Soils are removed first, then grease and after the material is treated with acid to also remove scaling. Each and every after one step the material is rinsed two to three times to make sure that none of the chemicals per step is left. The pre-treatment phase of electroless nickel plating is highly important since this determines the quality of the finished product. After this, activation is commenced with a weak acid for metal substrates or a propriety solution for non-metals. For finishing, the material needs to be also treated with an anti-oxidation and anti-tarnish chemical such as chromate and then rinsed again very carefully to prevent staining the finished nickel coat.