Investigation of dispersion stability and lubricating performance of nickel oxide nanolubricants

Abstract

The current manufacturing industry demands energy saving tribosystems by controlling the tribological factors like friction and wear. The lubricating agents are used for enhancing the effectiveness of mechanical tribo-systems. The hydrocarbon fractions present in the lubricating agents are having a tendency to polymerize, oxidize and thermally decompose at elevated temperature ranges and extreme pressure working conditions. The effective lubrication enhances the functional life of machinery that saves money and manpower. Recent studies reports that the mono-dispersion of nanomaterials into the conventional lubricating agents improves their thermophysical and lubricating characteristics. The nanolubricants are a new class of lubricating agent formulated by dispersing nanomaterials into conventional liquid lubricating fluids. In this study, an effort is made to investigate the dispersion, stability and lubricating properties of Nickel Oxide (NiO) nanolubricants. The NiO nanoparticles are synthesized by chemical sol-gel methods which are mono-dispersed into SN500 lubricating oil by ultrasonication technique and 0.1 wt%, 0.3 wt% and 0.5 wt% of NiO-nanolubricants are formulated. It is found that, the mono-dispersion stability of NiO-nanolubricants is dependent on the nanoparticle concentration and chemical stability results confirm that the functional structure of base lubricating fluid remains unchanged. The thermal properties are investigated at a dynamic temperature ranging from 40and#7484;C to 1000and#7484;C and observed that 0.1 wt% and 0.3 wt% of NiOnanolubricants can be used for the temperature dependent applications up to 200°C. Further, the lubricating characteristics NiO-nanolubricants like density, thermal conductivity, kinematic viscosity, flash and fire point are experimentally investigated. The viscosity of SN500 lubricating oil and 0.1 wt%, 0.3 wt% and 0.5 wt% of NiO-nanolubricants are investigated at temperature range of 40oC to 90oC. It is observed that, the viscosity of all weight fractions of the NiO-nanolubricants are linearly increasing with increasing nanoparticle weight fractions in which 0.5 wt% of NiOnanolubricants shows maximum viscosity enhancements. A Backpropagation Algorithm of Artificial Neural Network (ANN) correlation is proposed for estimating the nanoparticle concentration and temperature dependent viscosity of NiO-nanolubricants with minimum margin of deviations newline