Structural and tribological correlation of electrodeposited solid lubricating Ni-WSe2 composite coating

The present work investigates correlation between the structural and tribological behavior of pure Ni coating and Ni-WSe2 composite coatings at different WSe2 loading level (0, 0.1, 0.2, 0.5, 1 and 2 g/l). The developed coatings were characterized by X-ray diffraction technique (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) for phase, structure and compositional verifications, respectively. Structural and phase evolution of the coatings were correlated with roughness, microhardness and wear behavior. Characterization confirmed that beyond 0.5 g/l WSe2 content in the electrolyte, the composite coatings turned brittle and non-uniform with high surface roughness. The maximum hardness of 665 HV was observed in case of Ni-0.5 g/l WSe2 coating, whereas, the lowest average coefficient of friction of 0.068 was found in Ni-1 g/l WSe2 followed by 0.07 for Ni-0.5 g/l WSe2 coating. It was observed that Ni-0.5 g/l WSe2 coating possessed optimum mechanical properties and wear resistance.