A friend consulted and said that during the process of using acid tin plating additives, the workpiece plating layer may appear brittle and easy to fall off, which can seriously affect the welding performance of the plating layer. What causes this phenomenon?
Based on on-site experience and the characteristics of Sn-807, an acid tin plating additive, Bigley Technology has analyzed the following three main points:
1. The bath temperature is too low. Generally, the temperature of the Sn-807 plating solution should be controlled within the range of 20-30 ℃. When the plating temperature is too low, although the oxidation and hydrolysis of stannous salts and the consumption of brighteners are slow, the working current density becomes narrow, the coating is rough, easy to burn, and brittle.
2. Excessive brightener Sn-807B. Brightener Sn-807B can improve cathode polarization and make the coating fine and bright. When the ratio of additives in the plating solution is appropriate, the workpiece coating can achieve good toughness, weldability, and corrosion resistance. When the brightener Sn-807B is excessive, the workpiece coating is bright and brittle, resulting in poor adhesion and solderability.
3. The current density of the cathode is too high. When using Sn-807 plating solution, the cathode current density should be controlled within 0.5~3.5A/dm2. When the current density is too high, the obtained coating is relatively loose, rough, porous, brittle, and prone to burning at the edge.
Therefore, attention should be paid to the above three points in the process of using acidic tin plating additives to avoid the phenomenon of large brittleness and easy falling off of the workpiece coating, which affects the welding performance of the coating, and reduces the occurrence of failures. If you are interested in acid tin plating additives, please contact Bigley Customer Service for free samples and detailed technical information!
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