A technology that uses the principle of an electrolytic cell to deposit a metal coating with good adhesion but with different properties from the base material on mechanical products. The electroplating layer is more uniform than the hot dip layer, and is generally thinner, ranging from a few microns to tens of microns. Through electroplating, it is possible to obtain decorative protective and various functional surface layers on mechanical products, and to repair worn and processed workpieces.
In addition, it has different functions according to various electroplating requirements. Examples are as follows:
- Copper plating: used for primer to improve the adhesion and corrosion resistance of the electroplated layer. (Copper is easy to oxidize. After oxidation, the patina no longer conducts electricity, so copper-plated products must be protected by copper)
- Nickel plating: used for primer or appearance to improve corrosion resistance and wear resistance (among which chemical nickel is more wear-resistant than chrome plating in modern technology). (Note that many electronic products, such as DIN head and N head, no longer use nickel as a primer, mainly because nickel is magnetic, which will affect the passive intermodulation in the electrical performance)
- Gold plating: improve conductive contact impedance and enhance signal transmission. (Gold is the most stable and the most expensive.)
- Palladium nickel plating: Improve conductive contact resistance, enhance signal transmission, and have higher wear resistance than gold.
- Tin-lead plating: to improve soldering ability, soon to be replaced by other substitutes (because of lead, most of them are now plated with bright tin and matte tin).
- Silver plating: improve conductive contact impedance and enhance signal transmission. (Silver has the best performance, easy to oxidize, and conducts electricity after oxidation)
Electroplating is a method of laying a layer of metal on a conductor using the principle of electrolysis.
In addition to electrical conductors, electroplating can also be used on specially treated plastics.
The electroplating process is basically as follows:
Coated metal at the anode
The substance to be plated is at the cathode
The anode and cathode are connected by an electrolyte solution composed of positive ions of the metal plated.
After the direct current power supply is applied, the metal of the anode will be oxidized (loss of electrons), and the positive ions in the solution will be reduced at the cathode (get electrons) into atoms and accumulate on the surface of the cathode.
After electroplating, the aesthetics of the electroplated object is related to the magnitude of the current. The smaller the current, the more beautiful the electroplated object will be; otherwise, some uneven shapes will appear.
The main purposes of electroplating include prevention of metal oxidation (such as rust) and decoration. The outer layer of many coins is also electroplated.
Sewage produced by electroplating (such as ineffective electrolyte) is an important source of water pollution. The electroplating process has been widely used in the process of semiconductor and microelectronic component lead frames.
VCP: Vertical continuous electroplating, a new type of machine used for circuit boards, with better quality than traditional suspended electroplating.