1. Main components of nickel plating solution

(1) Nickel sulfate (NiSO₄·7H₂O)

The content in the plating solution varies; some companies standardize it to 180–220g/L, while others set it higher at 250–320g/L. If the nickel sulfate content is around 300g/L, the plating layer will have a uniform color and allow for higher current density, resulting in a fast deposition rate.

(2) Nickel chloride (NiCl₂·6H₂O)

The content in the plating solution varies; some companies standardize it to 30–50g/L, while others set it to 55–60g/L or 40–50g/L. Nickel chloride acts as an anode activator; on one hand, chloride ions can activate the anode, and on the other hand, nickel ions can replenish the concentration of nickel ions in the solution, both of which are effective components.

(3) Boric acid (H₃BO₃ )

Boric acid acts as a buffer, releasing hydrogen ions (H⁺) and borate ions (BO₃^3-). The content in the plating solution varies; some companies standardize it to 40–55g/L, while others set it to 35–50g/L or 30–45g/L. Boric acid helps stabilize the pH value in the nickel plating solution. During the nickel plating process, the pH value of the plating solution must be maintained within a certain range, typically standardized to 3.8–4.2, often set at 4.0. If the pH value is too low, H⁺is prone to discharge, reducing the current efficiency of nickel plating and causing pinholes in the plating layer; if the pH value is too high, the plating solution becomes turbid, and metal ions around the cathode can be incorporated into the plating layer in the form of metal hydroxides, degrading the mechanical properties and resulting in a rough appearance. Therefore, strict control of the pH value is essential during production. In addition to stabilizing the pH value, boric acid also helps the plating layer crystallize finely and prevents burning. When using high current density, a plating solution with a higher boric acid content (40g/L) should be used.

2.Method for preparing the plating solution

Calculate the required amount of chemicals based on volume, dissolve them separately in hot water, mix them in a container, dilute with distilled water to the required volume, let it stand to clarify, introduce the plating solution into the plating tank using filtration, then add the already dissolved sodium dodecyl sulfate solution, stir evenly, take samples for analysis, and after adjustments and successful trial plating, it can be used for production.