Experimental studies on viscosity and tribological characteristics of blends of vegetable oils with CuO nanoparticles as additive

Abstract

High biodegradability, renewability and low toxicity of vegetable oils make them excellent lubricating base oils. Coconut oil (CO) when usedas a lubricant at metallic interfaces exhibits a low coefficient of friction but high wear rate compared to mineral oils, which limits its applicationas a commercial lubricant, whereas mustard oil (MO) exhibits better wear resistance. The main objective of this work is to obtain an optimalblend of MO and CO to be used as an environment-friendly base oil and to add an optimal concentration of nanoparticles as an additive toimprove the viscosity and reduce the friction and wear rate. The experiments are performed on the blends with MO/(CO + MO) ratio rangingfrom 10 to 50% and the addition of CuO nanoparticles with concentrations ranging from 0 to 0.4 wt.%. The viscosity and tribological analysesof the CO, MO, their blends, and mineral oil (SAE20W40) are carried out and compared. Both the coefficient of friction and wear scardiameter are found to be lower than those of mineral oils. Further improvements in the tribological characteristics of the blends areattained by the addition of CuO nanoparticles in small concentrations, 0.2 wt.% being optimal.