A technique for depositing metal coatings with good adhesion but different properties and substrate materials on mechanical products by using the principle of electrolysis cell. Electrodeposited layer is uniform, generally thin, from a few microns to dozens of microns. Through electroplating, decorative protective and various functional surface layers can be obtained on mechanical products, and can also repair worn and processing errors of the workpiece.
In addition, according to a variety of electroplating requirements have different roles. Examples are as follows:
1. Gold plating: improve conductive contact impedance and enhance signal transmission. Gold is the most stable and the most expensive.
2. Silver plating: improve conductive contact impedance and enhance signal transmission. (silver has the best properties, is easy to oxidize, and conducts electricity after oxidation.)
3. Copper plating: used as a base to enhance the adhesion and corrosion resistance of electrodeposit. (copper easy oxidation, oxidation, copper no longer conduct electricity, so copper plating products must do copper protection)
4. Nickel plating: base with or make appearance, improve the corrosion resistance and wear resistance, (among which, chemical nickel is more wear resistance than chromium plating in modern process). (note that many electronic products, such as DIN head and N head, no longer use nickel backing, mainly because nickel is magnetic, which will affect the electrical performance of passive intermodulation)
5. Palladium nickel plating: improve conductive contact impedance, improve signal transmission, wear resistance higher than gold.
6. Tin lead plating: to improve the welding ability, quickly replaced by other substitutes (because of the lead is now mostly replaced by bright tin and fog tin).