Electroless plating is a method of obtaining a metal alloy by using an oxidation-reduction reaction on a plated part having a catalytic surface in the absence of electricity. It is a newly developed new technology. The United States, Britain, Japan, Germany and other countries, their industrial output value is increasing at a rate of 15% per year. It is widely used in machinery, electronics, plastics, molds, metallurgy, petrochemicals, ceramics, hydraulics, aerospace and other industrial sectors, and is one of the most promising new technologies.
All chemical deposition methods can be divided into three categories (generalized classification):
1. Displacement plating (ion exchange or charge exchange deposition):
A metal is immersed in a solution of a metal salt of a second metal, the surface of the first metal being partially dissolved, while a second metal is spontaneously deposited on the surface of the first metal. In the case of ion exchange, the base metal itself is a reducing agent.
The most widely used base metals (Me1) are copper, iron and nickel, and the most widely used coating metals (Me2) are gold and copper. If a nail is immersed in a solution of copper sulfate, a thin layer of copper is plated on the nail. However, its practical application is limited because once the surface of the base metal is covered by the metal (Me2) in the solution, the process stops immediately. Therefore, the maximum thickness is very small, and the bonding strength is not as good as true electroless plating. Due to the poor quality of the coating and the limited thickness, the application is very limited.
2. Contact plating:
A method of depositing a metal to be plated in contact with another metal or another of the same metal and immersed in a salt solution of the deposited metal.
When the surface of the conductive substrate to be plated is in contact with a more active metal than the metal to be deposited in the solution, contact deposition is formed. A galvanic cell pair is formed between the substrate and the contact metal, wherein the contact metal is the anode and dissolution occurs, and the substrate to be plated serves as the cathode, and the metal is deposited on it. This method is the same as the electrodeposition reaction, except that the current comes from a chemical reaction and not from an external power source. This method has almost no practical significance, but it is of great significance for inducing chemical deposition on catalytically inactive substrates and acting as a "reaction initiator".
3. True electroless plating: Deposition of metal from a solution containing a reducing agent. Below we mention the chemistry
Nickel plating is such.
(b) Classification of electroless nickel plating:
1. According to the plating solution PH value classification: There are three types of acidic, neutral and alkaline.
2. According to the deposition temperature classification: There are three types of low temperature, medium temperature, high temperature.
3. Classified by alloy composition: There are three types of low phosphorus, medium phosphorus and high phosphorus.
4. Classified by reducing agent used: Ni-P, Ni-B, etc.
All chemical deposition methods can be divided into three categories (generalized classification):
1. Displacement plating (ion exchange or charge exchange deposition):
A metal is immersed in a solution of a metal salt of a second metal, the surface of the first metal being partially dissolved, while a second metal is spontaneously deposited on the surface of the first metal. In the case of ion exchange, the base metal itself is a reducing agent.
The most widely used base metals (Me1) are copper, iron and nickel, and the most widely used coating metals (Me2) are gold and copper. If a nail is immersed in a solution of copper sulfate, a thin layer of copper is plated on the nail. However, its practical application is limited because once the surface of the base metal is covered by the metal (Me2) in the solution, the process stops immediately. Therefore, the maximum thickness is very small, and the bonding strength is not as good as true electroless plating. Due to the poor quality of the coating and the limited thickness, the application is very limited.
2. Contact plating:
A method of depositing a metal to be plated in contact with another metal or another of the same metal and immersed in a salt solution of the deposited metal.
When the surface of the conductive substrate to be plated is in contact with a more active metal than the metal to be deposited in the solution, contact deposition is formed. A galvanic cell pair is formed between the substrate and the contact metal, wherein the contact metal is the anode and dissolution occurs, and the substrate to be plated serves as the cathode, and the metal is deposited on it. This method is the same as the electrodeposition reaction, except that the current comes from a chemical reaction and not from an external power source. This method has almost no practical significance, but it is of great significance for inducing chemical deposition on catalytically inactive substrates and acting as a "reaction initiator".
3. True electroless plating: Deposition of metal from a solution containing a reducing agent. Below we mention the chemistry
Nickel plating is such.
(b) Classification of electroless nickel plating:
1. According to the plating solution PH value classification: There are three types of acidic, neutral and alkaline.
2. According to the deposition temperature classification: There are three types of low temperature, medium temperature, high temperature.
3. Classified by alloy composition: There are three types of low phosphorus, medium phosphorus and high phosphorus.
4. Classified by reducing agent used: Ni-P, Ni-B, etc.
Outdoor Landscape Lights,Outdoor Led Motif Lights,Solar Led Motif Lights,Outdoor Solar Garden Lamp
Tianjin Jinji Optoelectronic Technology Co., Ltd. , https://www.tjjjgd.com