In the production process of using nickel plating additives, we sometimes find that the nickel plating solution contains zinc ions, which leads to the phenomenon of black stripes on the nickel plating layer of the workpiece.So where do the zinc ions in the plating solution come from?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's nickel plating additives Ni-301,Zinc impurities mainly come from zinc alloy workpieces or brass parts nickel-plated into the nickel-plating tank to dissolve,It is also possible that it was mixed into the plating solution from the nickel anode and from the treatment of the nickel bath with activated carbon containing zinc.
The nickel plating solution is very sensitive to zinc impurities. When the zinc impurity content in the plating solution is 20~60g/L, the nickel layer is bright and brittle;When the zinc impurity content is greater than 60g/L, black stripes will appear in the coating in the low current density area;When the zinc impurity content is higher, the deep plating ability of the bath decreases, the brittleness of the coating increases and there will be pinholes, black stripes deepen or the entire coating becomes black.
The general method for removing zinc impurities in nickel plating solution is chemical method:Heat the plating solution to 85~90℃, add crushed calcium carbonate under stirring conditions, adjust the pH value of the plating solution to 6.2-6.3, continue stirring for 2 hours, and filter after standing for 4 hours.It can also be treated by electrolysis: electrolysis is carried out at a cathode current density of 0.2~0.3A/dm2.
Because the treatment of zinc impurities is difficult to completely remove, it is necessary to stop production when using electrolysis and electrolysis, and it is effective after multiple treatments, and the loss of nickel salts is also relatively large.It is recommended to use Ni-395 Zinc Remover from Bigolly Technology to treat zinc impurities in the plating solution.It is especially suitable for nickel plating and impurity removal of zinc or zinc alloy workpieces.When using, add the zinc remover directly to the plating solution and stir it fully, and it can be produced without stopping production, and even if the Ni-395 zinc remover is added, it will not cause adverse consequences to the nickel plating solution.
Therefore, in the production process of using nickel plating additives, when there are zinc impurities in the plating solution, we should promptly deal with and control the content of zinc impurities in the plating solution, which can effectively reduce the occurrence of coating failures.If you are interested in nickel plating additives,please contact Bigolly customer service to get free samples and detailed technical information!
If you want to know more about nickel plating, you can check "Electroplating encyclopedia".