When we use sulfate tin plating brightener to produce, because of the particularity of stannous ions in the plating solution, the strong acidity of the plating solution and the lack of complexing agent in the plating solution, the maintenance and management of the plating solution are very important.So what parameters need to be paid attention to in the daily production process?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's sulfate tin plating brightener Sn-807, in the production process need to pay attention to these six points:
1, stannous sulfate. Stannous sulfate is the main salt of the plating solution, and its purity and storage time before use have a direct impact on the performance of the plating solution.The lower the purity, the less brightness of the prepared plating solution; The longer the storage time, the higher the content of tetravalent tin, the prepared plating solution is easy to be turbid, and the quality of the plating layer will also decrease.Therefore, the purity of stannous sulfate should be high and the storage time should be short.
2. Sulfuric acid. Sulfuric acid can provide sufficient conductive ions and also prevent the hydrolysis of tin ions. When the concentration of sulfuric acid in the bath is not enough, the bath is easy to be turbid, the dispersion ability is reduced, and the bright area is narrowed; When the sulfuric acid concentration is too high, the high current density area is easy to scorch, the cathode current efficiency will decrease, and the dissolution rate of the anode will be accelerated, resulting in an increase in the concentration of tin ions.
3. Anode.The anode should be a tin plate with a tin content of more than 99%, and be wrapped in an anode bag to prevent the anode sludge from falling into the plating solution and causing the coating to be rough.
4. The temperature of the plating solution.When the bath is often above 25 ℃, the compactness of the coating will decrease, the consumption of brightener will increase, and the oxidation rate of divalent tin ions will be accelerated.When the temperature is too low, the allowable current density range of the plating solution will be narrowed, and the deposition rate of the coating will decrease.
5. Current density. If the current density is too high, the crystallization of the coating at the corners of the workpiece is relatively rough, and problems such as pinholes and scorching will occur. At the same time, the consumption of brightener will be accelerated, and the conversion of divalent tin into tetravalent tin will also be accelerated. If the current density is too low, the low current area of the workpiece will decrease significantly.
6. Supplement and maintenance of sulfate electroplating tin brightener. Brightener should be added according to normal consumption. For example, Bigolly's consumption of brightener is 100-200 ml/kAh, and the consumption of softener is 200-300ml/kAh. When the plating solution is turbid, the plating solution can be treated with activated carbon, filtered and then supplemented with an appropriate amount of brightener to produce.
Therefore, we need to control the above 6 points in the production process of using sulfate tin plating brightener to ensure that the product has fine crystals and good solderability.If you are interested in sulfate tin plating brightener, please contact Bigolly customer service, you can get free samples and detailed technical information!
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