Investigation of lubrication performance and flow behavior of nano-fluids

Tribo-performance behavior of lubricants plays an instrumental role in conserving the energy while enhancing the machine life. Rheological properties of lubricants such as shear stress, shear rate, viscosity, viscoelastic behavior etc influence the tribo-performance behavior to a great extent. Modern Chemistry lays emphasis on the synthesis of nano additives that help enhance the rheological and tribological properties of lubricants ultimately leading to the conservation of valuable energy. In the present study the Rheological and Tribological performance behavior of hexagonal boron nitride (Hex-BN) nanofluids is presented. In order to study the effect of Hex-BN nano-particles on the rheological properties of lubricants two commercially available blended synthetic engine oils of same grades were selected. They were blended with 0.1 and 0.2% weight by weight of well dispersed Hex-BNnanoparticles. Standard test procedures were used to determine physicochemical properties and tribo-performance behavior of oils respectively. The study reveals that tested Hex-BN nanofluids behaved as non-Newtonian lubricants with shear thinning behavior at all tested temperatures and exhibited viscoelastic behavior at small shear rates. As a result of this anti-wear property showed an enhancement up to 12% for 0.2% Hex-BN indicating fair improvement in anti-wear properties of Hex-BN nanofluid. However, a marginal reduction in friction to the tune of 7% observed for the 0.2 wt% of Hex-BN nano-particles in the tested lubricants indicates that finished products have little scope to improve anti-friction properties under the influence of existing additives.