Role of size of hexagonal boron nitride particles on tribo‐performance of nano and micro oils

This research work was focussed on investigating the influence of size of hexagonal boron nitride (hBN) on the tribological performance of oils. Hexagonal boron nitride–added oils were developed using polyisobutylene succinimide as a dispersant (1 wt%) for hBN (4 wt%) particles in base oil. Dynamic light scattering–based studies were conducted to evaluate the stability of oils quantitatively. Physical properties evaluation was done for density, kinematic viscosity, and flashpoint. Tribo‐investigations were performed for anti‐wear and extreme‐pressure performance on 4‐ball tester. Anti‐wear and extreme‐pressure performance increased by ≈60% and ≈30%, respectively, for nano‐hBN–added oil, while 5 micron particles proved least performers among the selected sizes of hBN. Worn surfaces examination was done through scanning electron microscopy, energy‐dispersive X‐ray analysis, and atomic force microscopy.