Effects of WC addition on structure and hardness of electrodeposited Ni–W

Nickel–tungsten/tungsten carbide composites (Ni–W/WC) are fabricated by co-electrodeposition. Processing parameters including current density, particle content, and particle size are found to influence surface morphology and consequently the apparent hardness of the co-deposits. A cathodic current density below 0.2 A/cm2 and solid loading between 1 and 2 g/l are essential for providing deposits with non-porous and uniform structure. The use of 0.5 µm tungsten carbide particles and a current density of 0.1 A/cm2 results in a Ni–W/WC composite of fine and dense nodular structure with hardness of about 10 GPa, exceeding those of nanocrystalline nickel–tungsten alloys and comparable to that of hard chromium coating.