The size effect of molybdenum disulphide additives on friction and wear performance of lithium-thickened palm olein grease

Abstract

Concern over commercial mineral-based grease’s impact on the environment and its unrenewable resources requires a more sustainable alternative in lubrication. In this research, a palm olein-based grease was developed, and the effect of particle size of molybdenum disulphide (MoS2) additives on the grease performance was experimentally evaluated. Molybdenum disulphide additive of 0.5 wt.% concentration that varied in size was added to the palm olein grease. The friction reduction and wear characteristics of the developed lubricants were evaluated using a four-ball tribometer. The wear surfaces were analyzed by scanning electron microscope, energy dispersive spectroscopy and infinite focus microscope. It was discovered that MoS2 improved the grease performance, and a nano size of 90 nm exhibited the best performance in reducing friction coefficient, wear parameters and surface roughness. This study suggests the potential of palm olein-based grease with MoS2 additive to be used as a lubricant.