ELECTRODEPOSITION AND CORROSION RESISTANCE OF Ni–W–Al₂O₃NANOCOMPOSITE COATINGS

Abstract

Ni–W–Al 2 O 3 nanocomposite coatings were deposited on the low-carbon steel substrates from aqueous sulfate-citrate electrolytes containing various amounts of Al 3 O 2 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 Al 2 O 3 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 Al 2 O 3 nanoparticles (2 g/L) were added into the bath. In addition, with increase of Al 2 O 3 addition in the bath, a tendency of increase in hardness and corrosion resistance performance is observed.