When preparing the new tin plating bath solution, is there a large amount of gel-like turbid matter related to the tin plating brightener? In fact, it's not. It might be caused by the incorrect order in which the materials were added during the preparation process.
Stannous sulfate is not easily soluble in water. In neutral aqueous solutions, divalent tin ions are prone to hydrolysis, forming stannous hydroxide precipitate, with a small amount of Sn(OH)+ and [Sn2(OH)2]2- present.
When preparing the plating solution with tin brightener, the calculated amount of sulfuric acid should be slowly added to the water first. At this time, the solution temperature will rise rapidly. After it cools down slightly, we will arrange for the operator to add stannous sulfate. If this is not done, hydrolysis reaction is very likely to occur.
So, how should it be prepared correctly? Bigley engineers suggest operating in this way: Add 1/4 volume of pure water to the cleaned plating tank. While constantly stirring, slowly add the calculated amount of sulfuric acid (CP grade or AR grade). At this point, the solution temperature will rise to approximately 50-60 ℃. After slight cooling, while still hot (40-50 ℃), add the calculated amount of stannous sulfate and stir continuously until it is completely dissolved.
Then, add pure water to 95% of the required solution volume. When the temperature reaches room temperature, add the required amounts of various brighteners as per the instructions of the acidic tin plating brightener Sn-807, then add pure water to the required total volume, filter, and after analyzing and adjusting the composition, we can arrange for the trial plating.
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Guangdong Bigely Technology Co., Ltd. ,founded in 2003, is a high-tech enterprise integrating R & D，production, sales and service, specializing in the production of electroplating chemicals. As a fast growing electroplating chemicals supplier in China, Bigely has over 20 years' experience in electroplating additives production and own production base of 5000 square meters. We can produce 15,000 tons of electroplating additives every year, which can fully meet the needs of customers.
If you need our high-quality electroplating additives, please contact us. We can provide you samples for test, and also provide a series of services.
