Why does the film layer easily peel off when using trivalent chromium colorful zinc passivation solution?
2026-08-10 16:45:07
Why does the film layer easily peel off when using trivalent chromium colorful zinc passivation solution?Adding too much brightener, plus poor cleaning.In electrogalvanizing production, nearly 90% of faults are related to excessive brightener. The reason is that when plating plants encounter dull coatings, they often choose to add more brightener. Little do they know that this not only fails to improve the brightness of the coating but can also cause unnecessary problems. Blindly adding brightener increases the incorporation of more organic matter into the coating, which affects the adhesion of the subsequent passivation layer.As for cleaning: if zinc-plated workpieces are not properly rinsed with water, residual plating solution remains on the surface. After using the trivalent chromium colorful zinc passivation solution, the formed film tightly encapsulates these residues, making the film layer prone to peeling.How to solve it?
First, do not blindly add brightener. The additive ratio in the zinc plating bath must be kept within a reasonable range to ensure normal coating quality.How to determine whether the brightener is excessive? 
As a manufacturer of colorful zinc passivation solutions, Bigley recommends using the Hull cell test to make the judgment. If the relevant conditions are not available, one can consider manually shaking the parts to change the intensity of gas agitation and observe the brightness of the coating. This method can serve as an indirect way of judgment.As for water washing, it is recommended to soak the parts in 60°C hot water. Using ultrasonic cleaning would be even better.The pH value of the passivation solution is too highA high pH value means the acidity of the passivation solution is low. The film layer obtained from such a solution has good brightness, but its adhesion to the zinc coating is relatively poor. Some electroplating factories have reported that in severe cases, the film can peel off with just a light wipe.When using Bigley’s trivalent chromium colorful zinc passivation solution Zn-228, the pH value can be controlled within the range of 1.8–3.5 (at 8–10% by volume). Of course, in actual production, the situations faced by different electroplating factories vary, so it is necessary to analyze specific problems and control the pH value accordingly.If you are interested in trivalent chromium colorful zinc passivation solutions, please feel free to contact us at any time.
