Basic principle of plating line
In simple terms, electroplating refers to the deposition of a metal or alloy layer on the surface of a conductive body, such as a metal, by means of an electrolytic reaction in a solution with the help of an external direct current.
When plating, the plating metal or other insoluble material is used as the anode and the workpiece to be plated is used as the cathode, and the cations of the plating metal are reduced on the surface of the workpiece to be plated to form the plating layer. In order to exclude the interference of other cations, and to make the plating layer uniform and solid, it is necessary to use a solution containing plating metal cations as the plating solution to keep the concentration of plating metal cations constant. The purpose of electroplating is to coat the substrate with a metallic layer that changes the surface properties or dimensions of the substrate. Plating can enhance the corrosion resistance of the metal (the plating metal is mostly corrosion-resistant metal) to increase the hardness, prevent wear/improve electrical conductivity/smoothness/heat resistance and surface aesthetics.
Electroplating is an electrolytic process in which the metal sheet that provides the plated metal acts as an anode, the electrolyte is usually an ionic solution of the plated metal, and the plated material acts as a cathode. After the input voltage between the anode and the cathode, the metal ions in the electrolyte are attracted to the cathode, where they are plated after reduction. At the same time, the metal of the anode is re-dissolved to provide more metal ions in the electrolyte. In some cases, an insoluble anode is used, and a new group of electrolyte is added to replenish the plated metal ions during plating. Plating requires a low-voltage, high-current power supply to the plating bath and an electrolytic device consisting of a plating solution, parts to be plated (cathode), and an anode. The composition of the electroplating solution varies depending on the plating layer, but all contain the main salt that provides metal ions, complexing agents that can complex the metal ions in the main salt to form complexes, buffers that are used to stabilize the pH of the solution, anode activators and special additives (such as brightening agents, grain refiners, leveling agents, wetting agents, stress relievers and mist suppressants). The electroplating process is the reduction of metal ions in the plating solution to metal atoms by electrode reaction under the action of external electric field and metal deposition on the cathode. Therefore, it is a metal electrodeposition process including steps of liquid-phase mass transfer, electrochemical reaction and electrocrystallization.
