In the sulfate tin plating process, tetravalent tin is usually not directly involved in the formation of the plated layer, but it can occur due to oxidation of divalent tin in the plating solution. This oxidation can be triggered by several factors, including anodic reactions during the plating process, natural oxidation of the bath, and improper storage and handling.
Specifically, the oxidation of divalent tin to tetravalent tin is a common reaction when anodes are dissolved. This is particularly evident when the anode is not properly selected or is not properly maintained. In an acidic environment, the anode reaction should primarily form divalent tin, but if the anode is overconsumed or covered with an impermeable oxide layer, this prevents the proper formation of divalent tin, which in turn leads to the formation of tetravalent tin.
In addition, when the plating solution is exposed to air, dissolved oxygen can enhance the oxidation of tin to form impurity tetravalent tin. This process is exacerbated by higher temperatures of the sulfate tin plating solution, excessive agitation of the tin plating solution, or exposure of the tin plating solution to oxygen molecules in the air. Therefore, there should be no air leakage when the filter pump is pumping the filtration.
In addition, incorrect handling and storage practices can contribute to the conversion of divalent to tetravalent tin. For example, the use of impure chemicals or water sources, or improper disposal of tin-containing wastes, can introduce tetravalent tin into acidic tin solutions.
When we use Bigely sulfate tin plating brighteners, the process conditions and chemical balance in the plating solution need to be tightly controlled in order to prevent the generation and accumulation of tetravalent tin. Maintaining the proper anode material and construction, using a water source with low oxygen content, and implementing proper bath maintenance procedures are critical to preventing the formation of tetravalent tin. If the plating solution is turbid due to excessive tetravalent tin impurities, add Bigely tetravalent tin treatment agent to the plating solution and the solution will be clear again.
If you are interested in sulfate tin plating brightener and tetravalent tin treatment agent, please feel free to contact us.
