Nickel - Tungsten Carbide Composite Electroplating Coating

Tungsten carbide is a black six square crystal with metallic luster and hardness similar to that of diamonds. It is a good conductor of electricity and heat.

It has good chemical stability and is insoluble in water, hydrochloric acid and sulfuric acid. It is often used in welding metal protective coating, but some metals such as copper, because of the low melting point and is not suitable for spray welding operations, so the metal electroplating method was usually used protective coating. 

Composite plating by adding insoluble solid particles to the ordinary plating solution, so as to fully suspended in the plating solution, and in the process of plating and metal deposition, resulting in a composite coating wear resistance, self lubrication, corrosion resistance and decorative function. Tungsten carbide not only can form protective coating on copper surface by composite plating, but also has better wear resistance than nickel plating. 

Test process: select pure copper as cathode, the WC particles are added to the Watts nickelage solution, with twelve sodium dodecyl sulfate (SDS) 0.05 g/L, current density 2~4A/dm₂, temperature 40 ~ 60°C, stirring time for3 ~ 5 h. Nickel was prepared by electroplating——Tungsten carbide composite electroplating coating.

The order of influence of various factors on Ni - WC composite plating is WC addition >current density >temperature >plating time.

The process conditions were optimized by orthogonal test, the optimum formulation and process for the Watts nickelage solution 250 ~ 300 g/L, WC particles 35 g/L, H₃BO₃ 35 ~ 40 g/L, twelve sodium dodecyl sulfate 0.05 g/L, current density of 3 A/dm₂, temperature 40 ℃, stirring time for 4h. Under the optimal conditions, the mass fraction of WC in the Ni - WC composite coating is 29.95%, thickness is 103 m, red rust appears in neutral salt spray test time is 120 h, the corrosion resistance of pure Ni coating is superior to 96 h, increasing by nearly 25%.

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