Electroplating tin is a silver-white metal, non-toxic, with good welding and ductility, etc., the solution is mainly alkaline and acidic two categories, widely used in electronics, food, automotive and other industries.

Acid system is divided into sulphate, methanesulfonic acid system and fluoroboric acid system tin, etc., is characterized by stable solution, the coating brightness is high, the plating current high efficiency, easy to operate, but the poor dispersion of the bath, divalent Tin easy hydrolysis.

Alkaline tin plating solution is stable and the plating capacity is good, the disadvantage is high working temperature, low current efficiency, not bright and so on.

Methanesulfonic acid system is applied to continuous electroplating production line with high deposition rate and easy handling of waste water. The cost of fluoroborate tin plating solution is higher than that of sulfate bath, and there are some disadvantages such as fluoride pollution, Currently almost no use.

The actual production of more applications are sulfate, methanesulfonic acid system of acid bright tin plating process.

Sulfate bright tin plating solution is simple, mainly stannous sulfate, sulfuric acid, bright additives, stabilizers and other ingredients. When the content of stannous sulfate is high, the deposition rate can be increased. If the content is too high, the tin layer is rough and the content of the tin layer is low. The allowable cathodic current density is reduced, the coating is easy to be burnt, and the parts with simple shape are available. The lower the stannous sulfate content of the bath.

Sulfuric acid can increase the conductivity of tin plating solution to promote the dissolution of tin anode and can inhibit the hydrolysis of divalent tin in the bath. The high sulfuric acid content will accelerate the dissolution of the anode and increase the tin content in the plating solution. Rough. Sulfuric acid content is too low, will reduce the dispersion of the bath, the cathode current density decreases, affecting the brightness of the tin layer, so that the divalent tin easily hydrolyzed, resulting in turbidity of the bath.

Bright additives can make the tin layer bright, bright additives are generally aldehydes, phenols and other organic matter and solubilized surfactants and other components, too much light additive content will reduce the cathode current efficiency, while too much bright additives in the bath In the oxidation will accelerate the turbidity of tin solution.

The stabilizer is added to the tin plating solution in order to prevent the dibasic tin hydrolysis in the acid tin plating solution because the divalent tin is hydrolyzed and the milk is cloudy. Of course, in the electroplating process, the stabilizer needs to be brought out with the bath Supplement, in order to maintain the stability of acid bright tin plating solution. Currently on the market stabilizer is mainly complexing agent, antioxidant and reducing agent mixture, such as isonicotinic acid, ferrous sulfate, phenolic substances.

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