Influence of Fe2+ in the plating solution on the properties of the coating in the production process using acid tin plating brighteners

    In the production process of using acid tin plating brightener, since the workpiece is easy to bring Fe²⁺ into the plating solution during the pickling process, the Fe²⁺ solution produced by the corrosion of the steel equipment is easily brought into the plating solution.So what effect does Fe²⁺ have on the performance of the tin plating layer?

    According to the field experience and the characteristics of the product acid tin plating brightener Sn-819, Bigolly Technology has made an analysis, mainly for the following three reasons:

    1. The effect of Fe²⁺ on the porosity of the coating.With the continuous increase of Fe²⁺ concentration in the plating solution, the porosity of the tin plating layer will gradually increase.When the Fe²⁺ concentration exceeds 10g/L, the porosity of the coating will increase sharply, and the quality of the coating will decrease.Therefore, it is necessary to maintain the Fe²⁺ concentration not more than 10g/L.

    2. The effect of Fe²⁺ on the corrosion resistance of the coating.With the continuous increase of Fe²⁺ concentration in the plating solution, the corrosion resistance of the coating will gradually decrease.This is because the increase of Fe²⁺ concentration increases the porosity of the coating, and the corrosion resistance of the coating also decreases.

    3. The effect of Fe²⁺ on tin slime.Fe²⁺ has a catalytic acceleration effect on the formation of tin slime.Fe²⁺ and Sn²⁺ in the bath will compete for dissolved oxygen in the bath, resulting in the production of Fe³⁺, Fe³⁺ reacts with Sn²⁺, and when Sn⁴⁺ is formed, Fe²⁺ will be generated again, forming such a redox cycle process.In the process of tin plating, Fe²⁺ is affected by the reduction of cathodic current, which will corrode the coating of the tin plate, thereby reducing the current efficiency of tin plating.

    Therefore, in the production process of using acid tin plating brightener, Fe²⁺ in the plating solution should be treated regularly to reduce its influence on the performance of the tin plating layer.If you are interested in acid tin plating brightener, please contact Bigolly customer service, you can get free samples and detailed technical information!   

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