During the process of using acidic zinc plating brighteners, we sometimes find that the coverage ability of the zinc coating on the produced workpiece is poor, especially in the blind holes or recesses of the workpiece where the coating is thin or lacking. What is the reason for this?
Based on on-site experience and the characteristics of the acidic zinc plating brightener BZ-528, Bigley Technology has analyzed the following four main points:
1. The content of Potassium chloride (or sodium chloride) in the bath is too low. In the acid zinc bath, when the content of Potassium chloride (or sodium chloride) is too low, the dispersion ability and deep plating ability of the bath will be significantly reduced, and the range of bright current density will also be narrowed. Therefore, the content of Potassium chloride (or sodium chloride) in the plating solution with brightener BZ-528 should be regularly analyzed and controlled within the process range.
2. The plating solution temperature is too high. When the temperature of the plating solution is too high, the adsorption of the brightener is weak, and the brightness, dispersion performance, and deep plating ability of the workpiece coating will significantly decrease. Therefore, the temperature of the plating solution should be well controlled during the production process. When the plating solution temperature is high, production should be suspended or cooling measures should be taken to reduce the temperature of the plating solution.
3. Insufficient brightener in the plating solution. Brightener can produce brightness and leveling effects. When the brightener in the plating solution is insufficient, the brightness and leveling performance of the coating will deteriorate. Therefore, in the plating solution of brightener BZ-528, the Hull cell should be regularly used to determine the amount of brightener in the plating solution, ensuring that the amount of brightener in the plating solution is within the process range.
4. The impact of lead impurities. Lead impurities mainly come from impure Zinc chloride or zinc anode. Lead impurities mainly affect the low area of the coating, resulting in streaks or missing plating in the low area of the coating. When there is the influence of lead impurities in the plating solution, it should be determined through Hull cell experiments first and then treated with zinc powder or low current electrolysis in a timely manner.
So, when we use acidic zinc plating brighteners and the coating's coverage ability is poor, we can use the above four points to promptly eliminate faults and reduce losses caused by faults. If you are interested in acidic zinc plating brighteners, please contact Bigley customer service for free samples and detailed technical information!
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