The method of plating a layer of nickel on metal or certain non-metals through electrolysis or chemical methods is called nickel plating. Nickel plating is divided into electroless nickel plating and chemical nickel plating.
Nickel electroplating is in an electrolyte composed of nickel salt (called main salt), conductive salt, pH buffer, and wetting agent. Metal nickel is used as the anode, and the cathode is the plated part. Direct current is passed through, and deposit a uniform, dense nickel coating on cathode (plated part). Bright nickel is obtained from the plating solution with brightener added, while dark nickel is obtained from the electrolyte without brightener added.
The electroplated nickel layer has high stability in the air. Because metallic nickel has strong passivation ability, it can quickly form an extremely thin passivation film on the surface, which can resist corrosion from the atmosphere, alkali and certain acids. The crystals are extremely fine and have excellent polishing properties. The polished nickel coating can obtain a mirror-like glossy appearance and can maintain its luster for a long time in the atmosphere. Therefore, electroplated layers are often used for decoration. The hardness of nickel plating is relatively high, which can improve the wear resistance of the product surface. Nickel plating is commonly used in the printing industry to improve the hardness of lead surfaces.
Uniform thickness and good throwing ability are a major feature of electroless nickel plating, which is also one of the reasons for its wide application. Electroless nickel plating avoids uneven thickness of the electroplated layer due to uneven current distribution. During electroless plating, as long as the surface of the part is in contact with the plating solution, the components consumed in the plating solution can be replenished in time. The thickness of the coating on the plated parts is basically the same, even in grooves, gaps, and blind holes. The plated parts will not hydrogen permeate and there will be no hydrogen embrittlement. There is no need to remove hydrogen after electroless nickel plating. The functions of many materials and parts, such as corrosion resistance and high temperature oxidation resistance, are better than those of electroplated nickel. It can be deposited on the surface of various materials, such as: steel nickel-based alloy, zinc-based alloy, aluminum alloy, glass, ceramics, plastics, semiconductors and other materials, thereby creating conditions for improving the performance of these materials.