Nano-mechanical and nano-tribological characterization of Ni-Co-BN nano-composite coating for bearing applications

In this study, BN with the addition of Ni and Co have both been deposited on Aluminium -Silicon using the PVD technique. The composition and morphology of Ni-Co-BN coatings were investigated using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Mechanical studies on Ni-Co–BN coatings at low loads ranging from 500 to 1250 µN were conducted to investigate the effect of load on reduced modulus and hardness. Besides this, nano-wear studies were carried out with loads varying from 0.5 N to 1 N to investigate the distortion and cracking behavior of the coating. The results show that the reduced modulus and hardness of the Ni-Co-BN coating decreases as the load increases. The wear rate of the Ni-Co–BN coating increases with an increase in load from 4.08 × 10-5 to 1.608 × 10-4 mm3/m. The Ni-Co–BN coating displayed smooth wear scars on the sample surface with no fractures or debris, suggesting that the coated material flowed in a plastic way near the wear scar. The behaviour of the coating suggests its strong suitability for bearing applications.