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The basic principle and process flow of the electroplating process

  • Author:Gary Young
  • Release on:2023-07-18

The electroplating process is a method of laying a layer of metal on a conductor using the principle of electrolysis. Electroplating refers to a surface processing method in which the cations of the preplated metal in the plating solution are deposited on the surface of the base metal to form a plating layer by electrolysis, with the pre-plated metal as the cathode, in a salt solution containing pre-plated metal. Next, I will introduce you to the basic principles and process flow of the electroplating process!

The basic principle and process flow of the electroplating process

1. The basic principle of the electroplating process

Electroplating is an electrochemical process as well as a redox process. The basic process of electroplating is to immerse the part in a solution of metal salts as a cathode, the metal plate as an anode, and after connecting to a DC power supply, the required plating layer is deposited on the part. For example, when nickel plating, the cathode is to be plated with parts, and the anode is pure nickel plate, and the following reactions occur at the cathode and anode:

Cathode (plated): Ni2++2eNi (main reaction)

2H++2eH2(side reaction)

Anode (nickel plate): Ni-2eNi2+ (main reaction)

4OH--4e2H2O+O2 (side reaction)

Not all metal ions can be deposited from the aqueous solution, and if the side reaction of reducing hydrogen ions to hydrogen on the cathode is dominant, it is difficult for metal ions to precipitate on the cathode. According to experiments, the possibility of electrodeposition of metal ions from aqueous solutions can be obtained from the periodic table.

Anode is divided into soluble anode and insoluble anode, most of the anode and the coating corresponding to the soluble anode, such as: galvanized zinc anode, silver plating for silver anode, tin-lead alloy using tin-lead alloy anode, but a few electroplating due to the difficulty of anode dissolution, the use of insoluble anode, such as acid gold plating is mostly platinum or titanium anode, the main salt ion of the plating solution is supplemented by the addition of the prepared standard gold-containing solution, the chrome plating anode uses pure lead, lead-tin alloy, lead-antimony alloy and other insoluble anodes.

After reading the above basic principles of electroplating process, many people who are not science students still do not understand how electroplating works, so I will use a more understandable language to introduce the specific working principle of electroplating!

Electroplating requires a low-voltage, high-current power supply that supplies power to the plating bath and an electrolytic device consisting of the plating bath, the part to be plated (cathode), and the anode. The composition of the electroplating solution varies depending on the coating, but all contain a main salt that provides metal ions, a complexing agent that can complexe heavy metal ions of the main salt to form a complex, and a buffer for stabilizing the pH of the solution.

Anodizing activators and special additives. The electroplating process is a process in which the metal ions in the plating bath are reduced to metal atoms by electrode reaction under the action of an external electric field, and metal deposition is carried out on the cathode. Therefore, this is a metal electrodeposition process that includes steps such as liquid phase mass transfer, electrochemical reactions, and electrocrystallization.

In the plating tank containing the plating bath, the cleaned and specially pretreated parts to be plated are used as cathodes, and the anodes are made of plated metal, and the two poles are connected to the positive and negative poles of the DC power supply, respectively. Plating baths consist of aqueous solutions containing coated metal compounds, conductive salts, buffers, pH adjusters, additives, etc.

The basic principle and process flow of the electroplating process

2. Electroplating process

It generally includes three stages: pre-plating, electroplating and post-plating. Complete process:

(1.) Acid immersionfull plate electroplating copper pattern transferacid degreasing secondary countercurrent rinsemicro-etchingsecondary acid dipping tinning secondary countercurrent rinse

(2.) Countercurrent rinseacid immersionpattern electroplating copper secondary countercurrent rinsing nickel platingsecondary water washingdipping citric acidgold plating recovery2-3 stage pure water washing drying

The above is about the "basic principles and process flow of electroplating process", more information about the coating production line, welcome to follow us for updated information!

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