Microstructure and wear behaviour of pulse electrodeposited alumina nanoparticle reinforced Co-W nanocomposite coatings

The microstructure and wear behaviour of alumina nanoparticle reinforced Co-W alloy coatings have been investigated for potential replacement of hard chrome coatings. The composite coatings were pulse electrodeposited on steel substrates using a citrate bath. The effects of current density, in the range of 1-9 A dm(-2), on the particle reinforcement, phase/microstructure, microhardness, and wear properties of the coating have been studied. The coatings codeposited with current density of 5 A dm(-2) at 333 Hz pulse frequency and 33% duty cycle exhibited microhardness comparable to hard chromium coatings.