When we use alkaline zinc nickel alloy plating additive for production, sometimes the coating in the high current area of the workpiece has stripes, which will seriously affect the appearance and performance of the coating. So, how can this phenomenon occur?
According to the field experience and the characteristics of the zinc nickel alloy plating additive BZ-617 of the product, Bigolly Technology has made analysis for the following four reasons:
1. The nickel ion content in the plating solution is low.When the nickel ion concentration in the plating solution is low, the nickel content in the alloy coating is correspondingly low.When the nickel content is less than 12%, the low area of the coating will be brown, while the high area will have stripes.
2. The bath temperature is high.The change of bath temperature will affect the deposition rate of nickel. When the temperature is high, streaks are easy to appear in the high current area of the coating.Therefore, the temperature of the plating solution should be controlled at 20~28 ℃.
3. The concentration of complexing agent is low.The complexing agent can prevent the precipitation of nickel hydroxide in the bath, improve the passivation ability of the coating in the low current zone and the dispersion ability of the bath.When the concentration of the complexing agent is low, the thickness difference between the high and low areas of the coating is large, the passivation effect is poor, and the coating in the high current area is prone to stripes.Therefore, the concentration of complexing agent should be controlled within the process range.
4. The concentration of brightener is low.Brighteners can improve the brightness of the coating, improve the alloy distribution of the coating, and limit the deposition of high current areas.When the concentration of brightener is low, the brightness of the coating is poor, and the deposition speed in the high area of the coating is fast, so the stripe phenomenon is easy to appear.Therefore, the concentration of brightener should be controlled at 5~7ml/L (hanging plating) or 3~5ml/L (barrel plating).
In this way, we should pay attention to the above four points when using alkaline zinc nickel alloy plating additives, which can avoid the stripe phenomenon of the workpiece coating and affect the appearance and performance quality of the coating, and reduce the occurrence of failures.If you are interested in alkaline zinc nickel alloy plating additives, please contact the Bigolly customer service for free samples and detailed technical information!
If you want to know more about zinc nickel alloy,you can click to view "Common problem".