Basic principles and process flow of electroplating process
The electroplating process is a method of applying a layer of metal to a conductor using the principle of electrolysis. Electroplating refers to a surface processing method in which a salt of a pre-plated metal is used as a cathode, and the cations of the pre-plated metal are deposited on the surface of the base metal by electrolysis to form a coating. Next, I will introduce the basic principle and process of the electroplating process for you!
1. Basic principles of electroplating process
Electroplating is an electrochemical process and a redox process. The basic process of electroplating is to immerse a part in a solution of a metal salt as the cathode and a metal plate as the anode. After connecting the DC power supply, the required Plating. For example, when nickel plating, the cathode is the part to be plated, and the anode is a pure nickel plate. The following reactions occur at the cathode and anode respectively:
Cathode (plating): Ni2 ++ 2e → Ni (main reaction)
2H ++ 2e → H2 ↑ (Side reaction)
Anode (nickel plate): Ni-2e → Ni2 + (main reaction)
4OH-－4e → 2H2O + O2 (side reaction)
Not all metal ions can be deposited from an aqueous solution. If the side reaction of reduction of hydrogen ions to hydrogen on the cathode is dominant, metal ions are difficult to precipitate on the cathode. According to experiments, the possibility of metal ions being electrodeposited from aqueous solutions You can get a certain pattern from the periodic table.
The anodes are divided into soluble anodes and insoluble anodes. Most anodes are soluble anodes corresponding to the plating, such as: zinc anodes are zinc anodes, silver anodes are silver anodes, tin-lead alloys are tin-lead alloy anodes, but a few are electroplated. Due to the difficulty of dissolving the anode, insoluble anodes are used. For acid gold plating, platinum or titanium anodes are mostly used. The main salt ion of the plating solution is supplemented by adding a prepared standard gold-containing solution. The chrome-plated anodes use pure lead and lead-tin alloys. Insoluble anodes such as lead-antimony alloys.
After reading the basic principles of the electroplating process above, many people who are not science students may still not understand exactly how electroplating works. Then I will introduce the specifics of electroplating in a more accessible language. How it works!
Electroplating requires a low-voltage, high-current power supply to the plating tank and an electrolytic device composed of a plating solution, a part to be plated (cathode), and an anode. The composition of the plating solution varies depending on the plating layer, but each contains a main salt that provides metal ions, a complexing agent that can complex the metal ions in the main salt to form a complex, and a buffering agent for stabilizing the pH of the solution.
Anode activator and special additives. The electroplating process is a process in which metal ions in a plating solution are reduced to metal atoms by an electrode reaction under the action of an external electric field, and metal deposition is performed on a cathode. Therefore, this is a metal electrodeposition process including liquid phase mass transfer, electrochemical reaction and electrode crystallization.
In the plating tank containing the plating solution, the to-be-plated part after cleaning and special pretreatment is used as the cathode, and the anode is made of plated metal, and the two poles are respectively connected to the positive electrode and the negative electrode of the direct-current power supply. The plating solution is composed of an aqueous solution containing a compound of a plating metal, a conductive salt, a buffer, a pH adjuster, and an additive.
2. Electroplating process
Generally includes three stages of pre-plating, electroplating and post-plating. The complete process:
(1.) Acid dipping → full plate electroplating copper → pattern transfer → acid degreasing → secondary countercurrent rinsing → micro-etching → secondary leaching → tinning → secondary countercurrent rinsing
(2.) Counter current rinsing → pickling → graphic copper electroplating → secondary counter current rinsing → nickel plating → secondary water washing → dipping citric acid → gold plating → recycling → grade 2-3 pure water washing → drying
The above is the related content of "Basic Principles and Processes of Electroplating Process". The information is provided by Guangdong Chuangzhi, a 25-year-old coating production line manufacturer. For more information about the coating production line, please follow us for updates!