Decorative Nickel Plating Bath Formulation
Nickel plating is a popular electroplating process used to provide corrosion resistance and an attractive finish to decorative and functional items. The process is simple and uses a special bath that contains different chemicals depending on the desired finish. This article will discuss the process of nickel plating, as well as provide a formulation for a decorative nickel plating bath.
The first step in the nickel plating process is cleaning the surface to be plated. This can be done using an acid solution, such as phosphoric or chromic acid. The object must then be rinsed with water to remove any residue before the plating process can begin.
Once the surface is clean, the object is placed in a bath of nickel plating solution. This solution is composed of a nickel salt, such as nickel sulfate, and a reducing agent, such as sodium hydroxide. An electric current is then applied to the solution, causing the nickel salts to be reduced, depositing a thin layer of nickel onto the surface of the object being plated.
When plating decorative items, it is important to ensure that the plated finish is bright and even. To achieve this, the bath must contain specific chemicals, such as brighteners, cleaners, and levelers. The following formulation contains the necessary components to produce a decorative, bright nickel finish:
Nickel sulfate hexahydrate 99.3g/L
Sodium hydroxide (50% solution) 1.9 mL/L
Brightener compound PZ-7 (10% solution) 1.7 mL/L
Organic detergent TB9 (30% solution) 0.8 mL/L
Leveler compound PZ-7 (10% solution) 0.7 mL/L
Organic leveller LA-26 (10% solution) 0.3 mL/L
The pH of the bath should be adjusted to 10.5 with sodium hydroxide (50% solution). The operating temperature of the bath should be between 40°C and 45°C. Lastly, the current density should be between 15–25A/ft2.
By following this formulation and adjusting the pH, temperature, and current density appropriately, a decorative nickel finish can be applied to most items. The plated object should be rinsed with tap water after the plating process to remove any residual bath components and keep the nick finished from becoming tarnished.
Although nickel plating can be used for a variety of decorative applications, it is important to note that it is not the best choice for parts that may be exposed to extreme temperatures or mechanical forces. In these cases, another type of plating process, such as chrome plating, may be more appropriate.
In conclusion, nickel plating is an excellent choice for producing decorative finishes on items. It is important to use the correct bath formulation, adjust the pH, temperature, and current density appropriately, and rinse the plated surface with water after the process to ensure the best results.
