▎ 摘　　要

This article presents the experimental evaluation of rheological characteristics of graphene-gear oil (SAE EP-90) nanolubricant under varying concentration, temperature and shear rates.The nanolubricant samples have been prepared at concentrations varying from 0.3% to 1.8%. Aging test confirms good stability of the prepared nanolubricant samples even after an interval of 50 days. The rheological properties of the samples have been investigated over a temperature range of 25-80 degrees C and shear rate of 10-200 (1/s). Central Composite Design (CCD) of response surface methodology (RSM) was used for the experimental framework. A combination of concentration, temperature, shear rate (1.00594%, 25.0053 degrees C, 88.0967 (1/s)) yielded the maximum value of viscosity i.e. 396.113 mPa.s whereas the set (0.58333%, 65.5 degrees C, 118 (1/s)) gave the minimum value of viscosity i.e. 15.87 mPa s using Response Surface Methodology (RSM). A mathematical correlation with R-2 (0.9919) has been proposed to predict the relative viscosity of the nanolubricant using analysis of variance (ANOVA) which resembles closely with the experimental data (least deviation 0.256%).