The plated part is immersed in a chemical water containing the metal ions to be plated and the cathode is connected. An appropriate anode (soluble or insoluble) is placed on the other end of the chemical solution. After direct current is applied, a metal film is deposited on the surface of the plated part.
Five basic elements of electroplating
1. Cathode: the object to be plated, various plug-in terminals
2. Anode: If you want to plate metal, use soluble anode. If you want to plate precious metals (such as platinum), use insoluble anodes.
3. Electroplating potion: electroplating potion containing metal-plated ions
4. Electroplating tank: need to consider strength, corrosion resistance, temperature resistance, etc., can withstand and store electroplating solutions
5. Rectifier: equipment that can provide direct current.
Method of Electroplating
1. Barrel plating: more suitable for bulk objects, put the roller in the plating tank for electroplating
2. Rack plating: more suitable for medium and large objects, put the rack into the plating tank for electroplating
3. Coil plating: commonly known as continuous plating, drag the plated parts connected in series into the plating tank of the planned process for plating
Metallized
1. Electrolytic gold plating method: commonly known as electroplating, the plated part is immersed in a bath containing metal ions to be plated and connected to the cathode. An appropriate anode (soluble or insoluble) is placed at the other end of the bath.
After direct current is applied, the surface of the plated part That is, the method of depositing a layer of metal film, this method is the most widely used.
2. Electroless gold plating method: commonly known as chemical plating, this method does not use electricity. It uses displacement reaction or oxidation-reduction reaction to precipitate metal ions in the solution on the surface of the plated parts.
This method is mostly used on surfaces that are not easy to electroplating. Underplating of conductors, or special performance requirements, such as non-magnetic chemical nickel.
3. Melting gold plating method: commonly known as hot dipping method, the substrate metal with a higher melting point is immersed in a molten metal with a lower melting point, the surface of the substrate is melted, and then the coating is reached.
For example, for galvanized steel, the iron plate is immersed in molten zinc metal, and the surface of the steel is plated with a thick layer of zinc to achieve corrosion protection.
4. Spray gold plating method: commonly known as spray method, it uses high pressure gas or high pressure air to blow the metal melted by gas or arc onto the surface of the plated part. This method obtains a porous oxide particle coating, so the coating must have a certain thickness.
Generally, melting point metals are used. Because it is easy to operate like paint spraying, it is mainly used for anti-corrosion and decorative purposes.
5. Vapor phase gold plating method: It can be divided into two types: vacuum evaporation method and ion sputtering method.
A. The vacuum steaming method is commonly known as vacuum plating. For metal or non-metal, heat and evaporate the metal or metal salt to be plated in a vacuum to form a coating film of evaporated molecules on the surface of the plated part.
The purity of the film obtained by this method is higher than that of the electroplating method, and it has high temperature oxidation resistance, corrosion resistance and wear resistance. Used in plastic decoration gold plating and optical film gold plating purposes.
B. Ion sputtering method is to apply a few KV DC voltage in a vacuum, then photothermal discharge occurs between the electrodes to generate argon plasma ions, and the positive argon ions collide with the surface of the plated part due to the increase in the cathode potential, causing the surface of the plated part to splash.
The method of forming a film by spray evaporation. Most of the applied industries are wafer processing, optical discs, color filters, optical lenses... etc.
6. Impact gold plating method: a method in which plated parts, metal powder, impact objects, etc. are put into a rotating drum together, and a film is formed on the surface of the plated parts due to the impact of the rotation.
Purpose of Electroplating
1. Copper plating: for primer to enhance the adhesion and corrosion resistance of the electroplated layer
2. Nickel plating: for primer to enhance corrosion resistance
3. Gold plating: improve conductive contact resistance and enhance signal transmission
4. Palladium nickel plating: change conductive impedance, enhance signal transmission, better wear resistance than gold
5. Tin plating: enhance welding ability