Electroplating encyclopedia

The plating speed on the alkaline zinc workpiece is very slow, not necessarily because the alkaline zinc plating additive is excessively added

2022-05-23

    In the alkaline galvanizing process, the production line is designed according to the plating speed of the workpiece, which can ensure that the coating thickness of each batch of workpieces is uniform.But sometimes it will be found that the plating speed of the workpiece will be slower. Is this an excessive addition of alkaline zinc plating additive?

     Bigolly Technology made an analysis based on the field experience and the characteristics of the product's alkaline zinc plating additive BZ-515,When the alkaline zinc plating additive is added in excess, it may slow down the plating speed of the workpiece.

    This is because the alkaline zinc plating additives contain quaternized pyridine derivatives and synthetic polymer carrier brighteners.When they are excessive, the dispersing ability of the plating solution will be reduced, and the plating speed of the low area of the workpiece will be slower at this time.Therefore, when the alkaline zinc plating additive is excessively added in the bath, the addition of the additive should be stopped within a period of time.


    In addition to the excessive addition of alkaline zinc plating additives, the slow plating speed on alkali zinc workpieces may also be caused by the following two situations:

    1. The zinc content in the alkaline zinc bath is low.When the zinc content in the bath is low, the cathodic polarization increases and the dispersing ability is good, but the deposition rate is slow.We should regularly analyze and ensure that the content of zinc and alkali in the bath is within the process range during production.

    2. The temperature of the bath is lower or the current density is lower.When the temperature is low, the conductivity of the plating solution is poor, and the deposition rate of the coating is slow;When the current density is low, the crystallization of the coating is finer, but the plating speed is slower.We should pay attention to whether the temperature and current density of the plating solution are within the working range during production. Generally, when producing at 20~30℃, the current density is recommended to be 1.5~2A/dm2.

    Therefore, the slow plating speed on the alkali zinc workpiece is not necessarily due to the excessive addition of alkali zinc plating additives.The content of zinc and alkali in the bath, as well as operating conditions such as bath temperature and current density, should be analyzed to ensure that these conditions are within the process range.If you are interested in alkali zinc plating additives, please contact Bigolly customer service to get free samples and detailed technical information!

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