Novel investigation on tribological properties of Ni–P–Ag–Al2O3 hybrid nanocomposite coatings

In this research, silver and alumina particles were co-deposited within Ni–P matrix to obtain Ni–P–Ag–Al2O3 hybrid coating. The structure of coatings was analyzed by X-ray diffraction and the tribological properties of deposits were evaluated by pin on disc tribometer. 3D optical profiler and scanning electron microscopy were used to study wear rate and worn surfaces. The results showed that Ni–P–Ag and Ni–P–Ag–Al2O3 coatings have the self-lubrication property and maximum hardness (∼1310 HV) and wear resistance were obtained for Ni–P–Al2O3 coating. Also, Ni–P–Ag–Al2O3 hybrid nanocomposite coating had higher wear resistance than Ni–P and Ni–P–Ag coatings. Moreover, the best conditions was achieved for heat treated hybrid coating in the concentration of 30 mg/L silver and 150 mg/L alumina in the plating solution.

► Ni–P–Ag–Al2O3 hybrid coating was easily deposited by electroless plating.
► Maximum wear resistance was obtained for heat treated Ni–P–Al2O3 composite coating.
► Highest lubrication was achieved for heat treated Ni–P–Ag composite deposit.
► Ni–P–Ag–Al2O3 could provide both characteristics of wear resistance and lubrication.