In the production process of using nickel plating brighteners, we often encounter the problem of poor adhesion of the nickel plating layer, which cannot meet the appearance, texture, corrosion resistance and other performance requirements of the workpiece. So what are the reasons for poor adhesion of the workpiece coating?
Bigely Technology has conducted an analysis based on on-site experience and product characteristics, mainly for the following five reasons:
1.Poor pre-processing. The main manifestation is that the oil removal is not clean enough or the water washing after oil removal is not clean enough, which can easily cause the nickel plating layer to flower, and in severe cases, the coating may bubble. In addition, the influence of copper and lead impurities or excessive acid washing in the acid activation tank can also lead to poor adhesion of the coating on the workpiece.
2.The pH value of the plating solution is relatively high. When the boric acid content in the plating solution is insufficient, it will increase the pH value of the plating solution. When the current density is high, hydrogen evolution on the cathode will cause local pH value to increase and form co deposition of basic sodium carbonate and nickel, resulting in peeling of the nickel plating layer.
3.The temperature of the plating solution is too low and the current density is too high. The temperature of the plating solution is low, and the diffusion rate of metal ions is slow. When the current density is high, it is easy to cause an increase in concentration polarization at the metal interface, resulting in the production of basic nickel carbonate. In addition, the low temperature and high current density of the plating solution result in high internal stress in the coating, which can cause poor adhesion of the nickel layer.
4.There are many impurities in the plating solution. Excessive content of nickel plating brightener or organic impurities can cause the coating to become brittle and bubble. Excessive copper impurities can displace onto the metal surface, resulting in poor adhesion of the coating; Excessive iron impurities can cause the pH value of the plating solution to become unstable, resulting in the inclusion of iron hydroxide in the coating and poor adhesion of the coating.
5.Improper other operations. During the nickel plating process, the formation of bipolar electrodes or prolonged power-off time can lead to poor adhesion of the coating.
Poor adhesion of workpiece coating can seriously affect production efficiency and increase production costs. So, in the production process, we should pay attention to the pre-treatment of the workpiece and the control of the plating solution parameters to avoid poor adhesion of the workpiece, and also better use nickel plating brightener. If you are interested in nickel plating additives, please contact Bigely customer service for free samples and detailed technical information!
