In the production process of using sulfate tin plating brightener, copper ions are easily generated in the plating solution, so what effect does copper ions have on the plating solution?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's sulfate tin plating brightener Sn-807,the effect of copper impurities, although uncommon, cannot be ignored.
Before tin plating, copper parts should be pickled with nitric acid or nitrate pickling solution to remove the oxide layer on the surface.The pickling solution contains a large amount of copper ions, which will be brought into the plating solution if not cleaned.However, copper parts that are not charged in the lower tank or complex parts that are not impact-plated are also prone to introduce copper impurities into the sulfate bright tin plating solution.In addition, copper rods, anode copper hooks, etc. may also be soaked in the plating solution and bring in copper impurities.
Copper impurities will cause dullness, yellowing, and even blackening in the current density area of the tin-plated layer.If the temperature range of the plating solution is narrow, the influence of copper impurities is more obvious.
So how should copper impurities in the plating solution be removed?Take the plating solution for experiments in Hull cell, and plate at 0.5A for 3 minutes under stirring to determine the copper contamination.Then gradually add the prepared sodium sulfide solution of known concentration and stir, and the resulting black precipitate does not need to be filtered.Continue to add sodium sulfide solution until the failure caused by copper contamination in the low current area disappears, and determine the amount of sodium sulfide added.Add the amount of sodium sulfide solution to the plating tank, stir and precipitate for one night (if you want to treat tetravalent tin at the same time, you can add flocculant to process it together), filter and take the clear solution and try plating again.
This is the influence of copper impurities in the production process of sulfate tin plating brightener and the treatment method, which can effectively reduce the occurrence of failures.If you are interested in sulfate tin plating brightener, please contact Bigolly customer service to get free samples and detailed technical information!
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