WITHDRAWN: Performance analysis of mineral oil based nano-lubricants with sulphur impregnated reduced graphene oxide nanosheets

Abstract

Abstract Nano lubricants offer a great advantage in increasing the performance of the refrigeration systems by improving the tribological properties. Researchers found out that better lubrication properties can be achieved through nanolubricants by adding nanoparticles at optimum concentrations to the base lubricating oils. Reduction in frictional coefficients and wear rates contribute to the improvement of COP. Theobjective of the present work is to reduce the frictional coefficients and specific wear rate by adding reduced grapheneoxide (RGO) based hybrid nanomaterial to the lubricating oil (R134a oil) used in the refrigerator compressors. The RGO was synthesized by using modified hummers method, which was then impregnate with sulphur to obtain sulphur - reduced graphene oxide (SRGO) nanosheets. The nanolubricant was prepared by dispersing (SRGO) nanosheets in mineral oil using ultrasonic agitation. The dispersion stability and morphology studies were conducted using DLS and FTIR. Tribological studies were conducted using 4 ball friction tester and pin on disc tester. The thermophysical properties of the nanolubricants like thermal conductivity and viscosity were also estimated. The friction coefficient was found to decrease by 11% for addition of 0.1% by volume of SRGO nanosheets in mineral oil. The viscosity of nanolubricant containing 0.1% of SRGO nanosheets was 6.6% higher than base oil.