Common components of electroplating solution
Electroplating is the process of depositing a thin layer of metal or alloy on the surface of a substrate by electrolysis. The deposited layer of metal or alloy is called a plating layer. Plating gives the surface properties that are different from those of the substrate material. The most common applications of electroplating are corrosion protection and decoration, but functional plating is also becoming more widely used. Functional plating is the process of giving the surface of a plated part special physical and chemical properties, such as electrical/magnetic/photothermal properties/weldability/wear resistance and other surface properties.
The composition of the plating solution has an important influence on the structure of the plating layer, and its main components are as follows.
(1) Main salt, a salt that can deposit the required plating metal on the cathode.
(2) Complexing agent, which can generate complexes with the deposited metal ions in the solution.
(3) Conductive salt, a substance that increases the conductivity of the solution and does not complex the discharging metal ions.
(4) Buffering agent, used to stabilize the pH of the solution, especially near the cathode surface
(5) Stabilizer, to prevent hydrolysis of the main salt or oxidation of metal ions in the plating solution and keep the solution clear and stable.
(6) Anode activator, a substance that can eliminate or reduce the cathodic polarization of the anode during the plating process, which can promote the normal dissolution of the anode and increase the anode current density. (7) Additives, substances that are present in the plating solution at a very low level but have a significant impact on the performance of the solution and the plating layer. Additives can improve the performance of the plating layer and the role of plating quality, such as leveling agent / bright agent / anti-pinhole agent. Brightening agent is mainly used to increase the brightness of the plating layer, throwing away the polishing process. The role of wetting agent is to add the interfacial tension between metal and solution everywhere. Leveling agent can change the microscopic flatness of the metal surface. Stress relievers can lower the internal stress of the plating layer and improve the toughness of the plating layer. With the development of plating additives, the plating process is increasingly improved.
