Pulse electrodeposition and characterisation of Ni–SiC composite coatings in presence of ultrasound

Abstract

Ni–SiC nanocomposite coatings have been prepared by electrodeposition with the application of ultrasound at an ultrasonic frequency of 38 kHz with 200 W ultrasonic power. The observed cavitation effect due to ultrasonic application on surface morphologies, microstructures, mechanical, tribological and corrosion properties of the composite coatings were evaluated by using scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, Vickers microhardness, and corrosion tests, such as polarisation and electrochemical impedance spectroscopy (EIS) methods. Nanoparticles obtained with homogeneous distribution and reduced agglomeration in samples subjected to ultrasound indicated significant improvements in microhardness and wear resistance of the composite coatings compared to the coatings deposited without ultrasound. Additionally, the corrosion resistance results obtained from polarisation curves and EIS methods in 3·5 wt-%NaCl solution were found to be considerably improved. There appears to be a synergistic end result of improved mechanical properties, and superior wear and corrosion resistance in Ni–SiC composite coatings with the application of ultrasound in these electrodeposits.