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 you may find that the plating speed of the workpiece is relatively slow. Is this due to excessive addition of alkaline galvanizing additives?
Excessive addition of alkaline galvanizing additives may slow down the plating speed of the workpiece. This is because alkaline zinc plating additives contain quaternized pyridine derivatives and synthesized polymer carrier brighteners, and when they are excessive, they will reduce the dispersion ability of the plating solution, resulting in a slower plating speed in the lower areas of the workpiece. Therefore, when the alkaline zinc plating additive is added excessively in the plating solution, the addition of the additive should be stopped for a period of time.
The slow plating speed on the workpiece may be caused not only by excessive addition of alkaline galvanizing additives, but also by the following two situations:
1.The zinc content in the alkaline zinc plating solution is relatively low. When the zinc content in the plating solution is low, cathodic polarization increases and dispersion ability is good, but the deposition rate is slow. Regular analysis should be conducted during the production process to ensure that the content of zinc and alkali in the plating solution is within the process range.
2.The temperature of the plating solution is low or the current density is low. 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. During the production process, attention should be paid to whether the temperature and current density of the plating solution are within the working range. Generally, when producing at 20-30 ℃, the recommended current density is 1.5~2A/dm2.
So, the slow plating speed on workpieces produced by alkaline galvanizing process does not necessarily mean that the alkaline galvanizing additives are added excessively. The content of zinc and alkali in the plating solution, as well as the operating conditions such as plating solution temperature and current density, should be analyzed to ensure that these conditions are within the process range. If you are interested in alkaline galvanizing additives, please contact bigely customer service for free samples and detailed technical information!
