Five reasons for poor tin coating on nickel layer after workpiece is plated with nickel plating additive

Five reasons for poor tin coating on nickel layer after workpiece is plated with nickel plating additive

Sat Oct 29 10:00:46 CST 2022

    A customer asked that when using nickel plating additives for production, some electronic products are coated with nickel, and then the tin coating is easy to fall off during tin plating. What is the reason?

    According to field experience and the characteristics of nickel plating additive Ni-301, Bigolly Technology has made analysis, mainly including the following five points:

    1. Poor pretreatment before electroplating.Some workpieces are not cleaned due to insufficient concentration or temperature during degreasing, or there are residues on the surface that are not cleaned, which will affect the adhesion of the subsequent nickel coating or tin coating.During the production process, the concentration and temperature of the degreaser shall be adjusted to ensure that the workpieces are cleaned before treatment.

    2. Problems of nickel plating bath solution:For example, the nickel chloride content has a certain impact on the solderability of the nickel layer. The higher the nickel chloride content, the greater the coating stress, and the lower the content, the higher the porosity of the coating. The nickel chloride concentration should be adjusted to the normal range during production;If the pH value of the plating solution is abnormal, dilute sulfuric acid or nickel carbonate should be used to adjust the pH value of the plating solution;Low current electrolysis or activated carbon shall be used to treat the plating solution when it is polluted by oil or metal impurities.

    3. The thickness of nickel coating is not enough.The temperature and current density shall be checked during nickel plating. The thickness of nickel coating is not enough, the porosity of the coating is too high, and dirt or plating solution is easily mixed between the substrate and the coating, thus affecting the adhesion of the coating.

    4. If the washing time of nickel layer is too long and the surface is oxidized and passivated, the adhesion effect of subsequent tin plating will be affected.In the production process, the control of washing time shall be strengthened to prevent the oxidation and passivation of the coating.

    5. In the tin coating process after nickel plating, it is recommended to plate a dark nickel layer. Bigolly's semi bright nickel additive Ni-331 can be used, which has good adhesion with the base material and the tin coating.

    Therefore, we should pay attention to the above five points when using nickel plating additives to avoid poor tin coating or poor tin coating bonding force and reduce the failure rate.If you are interested in nickel plating additives, please contact the Bigolly customer service for free samples and detailed technical information!

    If you want to know more about nickel plating,you can click to view "Common problem".