What is plating? Types, advantage, application

During electroplating, the plating metal or other insoluble material acts as the anode, and the workpiece to be plated acts as the cathode. The cations of the plating metal are reduced on the surface of the workpiece to form a coating. To eliminate interference from other cations and ensure a uniform and durable coating, a solution containing the cations of the plating metal is used as the plating bath to maintain a constant concentration of the cations.

Galvanizing Principles and Process: Galvanizing deposits a layer of zinc on the surface of steel using electrochemical principles, primarily through the reduction of zinc ions in an electrolytic cell. The process includes pretreatment, degreasing, pickling, and passivation, electroplating, using direct current in the electrolytic cell to reduce and deposit zinc ions, and post-treatment, passivation, cleaning, and drying. The picture is hot dip galvanizing process.

Basic info of Nickel Plating: Nickel plating is primarily used to improve the corrosion resistance, wear resistance, and decorative properties of substrates. The nickel coating is dense and uniform, and is often used as an intermediate layer between other electroplated layers.
Nickel Plating Process: The nickel plating process includes pretreatment (degreasing, pickling, and activation), electroplating (electrolysis in a nickel sulfate or nickel chloride solution), and post-treatment (cleaning, passivation, and drying). Temperature, current density, and bath composition must be strictly controlled during this process.
Applications of Nickel Plating: Nickel plating is widely used in mechanical parts, electronic components, and decorative items, improving product performance and enhancing appearance.
 

Principles of Chromium Plating: Chromium plating involves electrolytically depositing a chromium layer in a chromic acid solution. 
Decorative chromium plating: Used to enhance appearance, it produces a thin, bright coating.
Hard chromium plating: Used to improve wear resistance and hardness, produces a thick, hard coating.
Chromium Plating Process Steps: The chromium plating process includes pretreatment, degreasing, pickling, and activation, electroplating (electrolysis in a chromic acid solution), and post-treatment (cleaning, passivation, and drying). The current density and plating bath composition must be controlled to prevent hydrogen embrittlement and chromic acid contamination.
Applications: Widely used in automotive parts, molds, tools, household appliances, faucet, etc.
Advantages: High wear resistance, high hardness, and a bright and attractive finish.
 

P rinciple of Copper Plating: Copper plating involves electrolytic deposition of a copper layer in a copper sulfate or copper cyanide solution. Copper ions are reduced on the electrode surface, forming a dense copper layer.
Copper Plating Process: The process includes pretreatment (degreasing, pickling, and activation), electroplating (electrolysis in a copper sulfate or copper cyanide solution), and post-treatment (cleaning, passivation, and drying). Control of the plating bath temperature, current density, and agitation intensity is crucial.
Applications of Copper Plating: It is used as a primer to enhance the adhesion and corrosion resistance of the electroplating layer. Copper plating is widely used in electrical contacts, conductive components, printed circuit boards, and other applications, providing excellent conductivity and adhesion.
 

Features of Precious Metal Electroplating: Due to the high value of precious metals, precious metal electroplating requires stringent process requirements and is primarily used for electronic components, decorative items, and high-end equipment.
Process of Silver and Gold Plating: The plating solutions for silver and gold plating are complex and difficult to control. Current density and plating time must be strictly controlled to ensure uniform coating quality and thickness.
Applications 
Silver plating: Used in electrical contacts, conductive parts, and decorative silverware, it offers excellent conductivity and antibacterial properties.
Gold plating: Used in high-end electronic components, connectors, jewelry, and other applications, it offers excellent conductivity, corrosion resistance, and decorative properties.
 

Electroplating methods include rack plating, barrel plating, continuous plating, and brush plating, depending on the size and batch size of the parts to be plated. Rack plating is suitable for general-sized parts, such as car bumpers and bicycle handlebars. Barrel plating is suitable for small parts, such as fasteners, washers, and pins. Continuous plating is suitable for batch-produced wire and strip. Brush plating is suitable for spot plating or repairs. Electroplating solutions include acidic, alkaline, acidic, and neutral solutions with chromium compounds. Regardless of the plating method used, the plating tanks and hangers that come into contact with the parts to be plated and the plating solution should be universal to a certain extent.

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