Effect of MoS2 nano-additive size and concentration on the wear performance of crude Jatropha-based bio-lubricant

Purpose Mineral-based lubricants are increasingly being restricted in many countries due to their negative environmental impact. Jatropha oil, a nonedible and biodegradable alternative, has the potential to be used as a bio-lubricant, with its tribological performance enhanced by incorporating nano-additives. This study aims to investigate the effect of MoS2 nano-additive size and concentration in Jatropha crude oil. Design/methodology/approach Crude Jatropha oil was blended with MoS2 nanoparticles of varying sizes (20–30, 50–60 and 80–90 nm) at concentrations of 0.5%, 1.0% and 1.5%. Anti-wear and extreme pressure tests were conducted using a four-ball tester per ASTM standards. A Taguchi L9 orthogonal array with four factors at three levels was used to assess the effects of additive size, concentration, load and speed. Wear surface morphology was analyzed to understand wear mechanisms. Findings The addition of MoS2 nanoparticles, along with their size and concentration, significantly improves the anti-wear and extreme pressure properties of Jatropha crude oil. According to variance analysis, additive size has the greatest influence on wear (36.42%), followed by load (31.03%), speed (21.12%) and additive concentration (11.43%). SEM images at 500x magnification clearly reveal wear reduction mechanisms such as mending, polishing and the formation of an adsorption film. Practical implications This work contributes to the development of a new lubricant; however, it is recommended to make it commercially viable for specific tribological systems is recommended. Originality/value The incorporation of MoS2 nanoparticles into crude Jatropha oil enhances its potential as an environmentally friendly, bio-based lubricant, making it a viable and competitive alternative for specialty lubricant.