The three main reasons for tin plating on copper bars:

(1) Improving conductivity: Tin plating can keep the surface of copper bars clean, providing a smooth and uniform contact surface, thereby reducing contact resistance. The alloying reaction between copper and tin can make tin plated copper more stable in conductivity and have a higher current carrying capacity than traditional pure copper wires.

(2) Preventing oxidation: Copper is prone to oxidation in humid or aerobic environments, forming a layer of copper green with poor conductivity. This not only affects the conductivity of copper, but also increases contact resistance, resulting in higher temperature rise. The tin plating layer can effectively block oxygen and water vapor, prevent copper busbar oxidation, and maintain its good conductivity.

(3) Improving heat dissipation capability: The thermal emissivity of tin and tin oxide is also different. Theoretically, the highest absolute blackbody emissivity is 1, while the emissivity of polished copper is only 0.15. Tin plating on the surface of copper bars is helpful for thermal radiation heat dissipation. In applications with high current density, good heat dissipation performance is crucial for the safe operation of equipment.

(4) Improving corrosion resistance: Copper is a metal that is prone to oxidation and can easily form copper green in air, which can lead to a decrease in conductivity and damage to structural strength. After tin plating the surface of copper bars, it can effectively prevent copper from reacting and corroding with the external environment, greatly enhancing the corrosion resistance of copper bars and extending their service life, especially in humid, salt spray or chemically corrosive gas environments.

(5) Improving welding performance: Tin is a good welding material, and tinned copper bars are easier to weld with other metal components, even without the need for flux, improving production efficiency and welding quality.

How thick is the tin plating layer: generally recommended 5-25 μ m

Indoor, generally anti-corrosion: about 5-12.5 μ m (recommended 12.5 μ m).

Damp, slightly corroded: about 12.5-25 μ m (recommended 25 μ m).

High corrosion, outdoor, high current: ≥ 25 μ m.

Compared with other metal coatings, tin plating can balance cost and performance, and is a cost-effective surface treatment method.

The principle of tin plating on copper bars

Tin plating of copper bars is the process of coating a thin layer of metallic tin on the surface of the copper bars. This process aims to prevent copper from being exposed to air and forming copper green, thereby extending the service life of the copper bars. Tin metal has good oxidation and corrosion resistance, which can effectively protect copper bars from external environmental erosion. In addition, the tinned copper bars also have good wear resistance and electrical conductivity, which can significantly improve the conductivity and transmission efficiency of the copper bars.

2、 The main technical steps of tin plating on copper bars

(1) Copper bar pretreatment: This is the foundation of the tin plating process, which requires cleaning, degreasing, rust removal, oxidation removal and other treatments on the surface of the copper bar to ensure the effectiveness of the subsequent tin plating process. The thorough pre-treatment directly affects the quality and stability of the tin plating layer.

(2) Coating solution coating: Apply a coating solution containing metallic tin evenly onto the surface of the pre treated copper bar to form a thin layer of metallic tin. This step requires precise control of the concentration and coating speed of the plating solution to ensure the uniformity and thickness of the tin plating layer.

(3) Drying: After coating is completed, the copper bars need to be placed in a dry place for drying treatment to ensure the integrity and stability of the tin plating layer. Temperature and humidity control during the drying process are equally important.

(4) Inspection: Conduct strict quality inspection on the tinned copper bars, including testing of the thickness, uniformity, adhesion, and other aspects of the tin plating layer. Only copper bars that meet the standards can enter the next process or be put into use.

Article source: Internet

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