Tribological properties of h-BN nanoparticles as lubricant additive on cylinder liner and piston ring

Friction and wear behaviour of different concentrations of hex-boron nitride (h-BN) nanoparticles in engine oil of grade SAE 20W50 were studied at various loads. These tribological studies were conducted using a four-ball wear test machine and a pin-on-disc universal tribometer. Anti-wear properties of SAE 20W50+h-BN were studied on the four-ball wear test machine as per ASTM D4172 standard. Friction and wear properties of SAE 20W50+h-BN on piston ring and cylinder liner tribo-pair were studied using the universal tribometer. Nanoparticles of h-BN mixed in lubricant showed excellent tribological performance. In most of the cases, h-BN nanoparticles as additive reduced the wear loss by 30-70% at various loads. The minimum value of coefficient of friction (0.0401) was found with SAE 20W50+3 wt% of h-BN at normal load of 100 N. Scanning electron microscopy and Raman spectroscopy were used for characterisation of h-BN and wear scars. Copyright (C) 2016 John Wiley & Sons, Ltd.