Synergistic role of carbonaceous reinforcements on multi length scale tribology of electrophoretically deposited nickel-boron nitride coatings

Electrophoretically deposited Ni-BN composite coating was strengthened with graphene (Ni-BN-Gr), carbon nanotubes (Ni-BN-CNT) and diamond (Ni-BN-D) carbonaceous reinforcements. Highest hardness (2.0 GPa) and elastic modulus (133.5 GPa) of Ni-BN-D coating than Ni-BN-CNT (1.96 GPa and 102.1 GPa, respectively), Ni-BN-Gr (1.94 GPa and 92.0 GPa respectively) and also from Ni-BN (1.89 GPa and 91.5 GPa, respectively) coatings was linked through high compressive stress (-601 MPa), dislocation density (8.9 x 10(15) m(-2)) and yield strength (4.4 GPa). The micro-scratching damage was contributed by ploughing and adhesion components, which were compared with that of experimental frictional values. Addition of graphene, CNT and diamond in Ni-BN composite showed a decrease in wear volume (from 1.66 x 10(-8) m(3) to 0.45 x 10(-8) m(3)) due to the synergetic lubricating effect of BN and carbonaceous reinforcements. Thus, Ni-BN-D restrict inception of multiscale wear and can be a potential three phase metal-ceramic coating for engineering and industrial applications.