In the production process of using nickel plating brightener, white fog appeared on the surface of the nickel plating layer of the workpiece, especially on the large area of the workpiece. What is the reason?
According to the site experience and the characteristics of nickel plating brightener Ni-301, Bigolly Technology has analyzed the following five points:
1. The content of nickel sulfate in the plating bath is high. In bright nickel plating solution, due to too much evaporation of water in the plating solution at the temperature of 50~60 ℃, the concentration of nickel salt is too high and white fog is easy to occur. Therefore, in the production process, it is better to control the content of nickel sulfate in the plating bath within the middle limit.
2. The content of boric acid in the plating bath is insufficient. During the production process, the boric acid content should be regularly analyzed and adjusted within the process range. When the boric acid content is insufficient, the pH value of the plating solution is not stable enough, and the coating is prone to rough, white fog, scorching and other phenomena.
3. Too much brightener in the plating solution. The main reason is that there is too much brightener or the ratio of brightener and softener is out of balance, resulting in white fog in the high current area of the workpiece and bright and black coating in the low current area. In this case, use activated carbon to treat the plating solution and adjust the brightener content in the plating solution.
4. The bath temperature is too high. When the temperature of the plating solution is too high, the evaporation of the plating solution will increase, and the nickel salt is easy to hydrolyze, which will generate nickel hydroxide precipitation, especially after the hydrolysis of iron impurities in the plating solution, it will generate iron hydroxide precipitation, resulting in pinholes, burrs, fog and other phenomena of the coating. Therefore, in the production process, the temperature of the plating solution should be strictly controlled within the process range.
5. The pH value of the plating solution is too high or too low. Generally, when the pH value of bright nickel plating solution is too high, although it has high cathode current efficiency, it is easy to generate alkaline nickel salt precipitation near the cathode, so that the nickel plating layer of the workpiece is easy to be mixed with these alkaline nickel salts, resulting in roughness, pitting, fogging and other phenomena; However, when the pH value is low, the anode solubility is good and the sludge is less, but the conductivity of the bath and the anode current efficiency are poor, which is prone to poor brightness, fogging, pinholes and other phenomena. Therefore, the pH value of the plating solution should be strictly controlled between 4.0 and 4.8 during the production process.
Therefore, we should pay attention to the above five points in the production process of using nickel plating brightener to avoid white fog on the surface of the workpiece coating.If you are interested in nickel plating brightener, please contact Bigolly customer service for free samples and detailed technical information!
If you want to know more about nickel plating, you can check "Electroplating encyclopedia".