ELECTRODEPOSITION AND CORROSION RESISTANCE OF Ni–W–Al2O3 NANOCOMPOSITE COATINGS

Abstract

Ni–W–Al2O3 nanocomposite coatings were deposited on the low-carbon steel substrates from aqueous sulfate-citrate electrolytes containing various amounts of Al3O2 nanoparticles. Their surface morphology, element and phase composition were carried out using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The corrosion resistance was carried out using the potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). It is shown that incorporation of Al2O3 nano-particles into amorphous Ni–W coating would transform its structure to being crystalline and influence its properties. The hardness sharply increases and corrosion resistance performance significantly decreases even after few Al2O3 nanoparticles (2 g/L) were added into the bath. In addition, with increase of Al2O3 addition in the bath, a tendency of increase in hardness and corrosion resistance performance is observed.