Effect of duty cycle on properties of Ni-P-(sol)Al2O3 nanocomposite coatings prepared by pulse-assisted sol-gel method

Ni-P-(sol)Al2O3 nanocomposite coatings were prepared on Q235 carbon steel substrates by pulse-assisted sol-gel method with duty cycles ranging from 20 to 90 %. The production, microstructural characterization, corrosion resistance, friction, and wear properties of Ni-P-(sol)Al2O3 nanocomposite coating were evaluated. The results show that when the duty cycle is 50 %, the surface quality and corrosion resistance of the composite coating are the best, the hardness is 559.6 HV, the corrosion rate is 2.433 mm y(-1), and the friction coefficient is 0.260. In this study, nano sol was used instead of traditional powder doping. The pulse-assisted sol-enhanced composite coating had good wear and corrosion resistance. This technique can effectively avoid the agglomeration of nanoparticles during the deposition of composite coatings while impacting and leveling the coating surface during the pulse interval to improve coating quality. Meanwhile, the highly dispersed sol saves time and energy consumption of mixed solution without dispersant or stabilizer.