Plastic electroplating - how to remove metal impurities in the nickel plating solution
How to remove metal impurities in nickel plating solution?
The removal method of iron ions: adjust the pH value of the nickel plating solution = 4. Add an appropriate amount of hydrogen peroxide (about 1 to 2 ml/L), stir the plating solution, and heat it to about 70 ° C. Use dilute sodium hydroxide solution to increase the pH of the plating solution to 6, stir for 2 to 3 hours, and then measure The pH value, if the pH is lowered due to the precipitation of iron, is raised to 6 again. Let stand overnight, add sulfuric acid after filtration, adjust the pH to the normal range, and then try plating.
Removal method of copper ions: Since the pH value of the hydrolysis precipitation of copper ions is close to that of nickel, the effect of removing copper by chemical methods is not good, and the loss of nickel is large. It is more economical and practical to remove copper impurities in nickel plating solution by electrolysis at low current density. That is, with a current density of 0.05-0.1 ampere/dm2, a corrugated iron plate is used as the cathode, and the electrolysis is performed under stirring until it can be produced normally.
Removal method of zinc ions: use dilute sodium hydroxide solution or calcium carbonate to increase the pH value of the plating solution to 6.2, heat it to 70 ° C, stir continuously for 1 to 2 hours, and then measure the pH value, if the pH value is lower than 6.2, it should be Continue to increase to 6.2, stand for more than 4 hours, then filter, and finally adjust the pH to the process range, and you can try plating. It can also be treated by electrolysis at a low current density (0.2 to 0.4 ampere/dm2).
