Fabrication of Ni-W-B4C composite coatings and evaluation of its micro-hardness and corrosion resistance properties

Boron carbide (B4C) particles were embedded in nickel-tungsten (Ni-W) coatings by pulse current electrodeposition technique. Physical properties of the composite coatings were studied by XRD, SEM, EDS and Vickers micro-hardness instrument. Corrosion protection of the deposited films was investigated utilizing potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS). Results exhibited that the addition of B4C nanoparticles into the Ni-W alloy can significantly improve the surface morphology and the micro-hardness of the composite coatings. The corrosion resistance of Ni-W-B4C nanocomposite is much better than Ni-W alloy deposit, especially when the concentration of B4C nanoparticles is 2 g/L in plating bath, the obtained Ni-W-B4C composite coating has the best surface morphology, the highest micro-hardness and the excellent corrosion resistance.