In the production process of using nickel plating brightener, the plating solution is weakly acidic,In addition to the deposition of the nickel layer, the workpiece of the cathode also has a small amount of hydrogen precipitation during nickel plating.The precipitation of hydrogen will affect the concentration of hydrogen ions in the plating solution, and will also affect the pH value of the plating solution.Therefore, the control of the pH value of the plating solution is an important factor affecting the quality of the coating.
In the formulations of various nickel plating brighteners, the pH control range in the bath is also different according to the content of the bath components.Generally, when the nickel sulfate content in the bath is high, the pH value can be controlled to be lower; and when the nickel sulfate content is low, the pH value can be correspondingly higher.
The pH value variation range of bright nickel plating solution should be controlled within the process range, for example, the pH value of Bigolly's nickel plating brightener should be controlled at 4.0~4.8.When the pH value of the bath is too low, the current efficiency of the cathode is reduced, the brittleness of the coating is relatively large, and sometimes there is no coating, and only hydrogen is precipitated.When the pH value is too high, the plating solution will be cloudy, and the deposited coating will have problems such as fogging, burrs, and brittleness.
If the pH value of the plating solution is too high, it can be adjusted with 10% dilute sulfuric acid. If the chloride ion in the plating solution is too low, it can also be adjusted with 1:1 hydrochloric acid.When the pH value of the plating solution is low, it can be adjusted with 5~10ml sodium hydroxide or potassium hydroxide solution. Note that it should be added slowly and vigorously stirred to avoid the formation of nickel hydroxide precipitation due to high local pH value.
Therefore, in the production process of using nickel plating brightener, we can control the pH value of the plating solution, which can reduce the failure rate and improve the production quality.