What should I do if the plating solution becomes cloudy and no longer clears?
It could be that the pH is too high, causing zinc ion hydrolysis. Acid should be added to adjust the pH.
Excessive impurities require filtration or electrolytic purification.
What causes white spots to appear on the passivation film or it to fall off?
Incomplete cleaning before passivation may be causing residual plating solution to react with the passivation solution.
The passivation time is too short or the passivation solution concentration is insufficient; extend the time or add more reagents.
What should I do if the coating thickness is uneven and varies significantly?
Adjust the hanger to ensure even current distribution across the part.
Check whether the plating solution is adequately stirred and add a stirrer if necessary.
What causes a large number of bubbles and a loose coating during electrolysis?
Excessive current density may cause a large amount of hydrogen ions to be released at the cathode (hydrogen evolution reaction).
The hydrogen ion concentration in the plating solution is too high (pH is too low); add alkali to adjust the pH.
What should I do if the coating surface has "streaks" or "mottling"?
The additive ratio is unbalanced; the concentrations of brightener and debonding agent need to be tested and adjusted.
Post-treatment cleaning is not thorough, leaving residual acid/alkali, requiring enhanced cleaning.