Thermal characteristics of yttria stabilized zirconia nanolubricants

Abstract

The transition from microparticles to nanoparticles can lead to a number ofchanges in its properties. The objective of this work is to analyze the thermal, tribological properties of yttria stabilized zirconia nanoparticles. Nanosized yttria stabilized zirconia particles were prepared by milling the yttria stabilized zirconia (10 μm) in a planetary ball mill equipped with vials using tungsten carbide balls. After 40 hours milled the yttria stabilized zirconia nanoparticles of sizes ranging from 70-90 nm were obtained. The phase composition and morphologies of the as-synthesized particles were characterized by energy dispersive X-ray analysis, scanning electron microscope, transmission electron microscope, thermogravimetric analysis and differential scanning calorimeter, and the images of the same were obtained. From TG-DSC analysis it was confirmed that, the yttria stabilized zirconia nanoparticles were heat stable under different thermal conditions which is due to the addition of yttria to pure zirconia. Due to this property of yttria stabilized zirconia nanoparticles, it can be widely used in high transfer application such as lubricant additives. The heat transfer properties ofautomotive engine lubricants were determined by utilization ofmeasured thermal conductivity, viscosity index, density, flash point, fire point and pour point revealed that lubricants with additive constituents have a significant effect on the resultant heat transfer characteristics of the lubricants.