Rheological behavior of lithium grease with CNTs/GNPs hybrid nanocomposite as an additive
Abstract
Purpose
The purpose of this paper is to investigate the rheological characteristics of graphene nanoplatelets (GNPs) and hybridized nanocomposite consisting of multi-walled carbon nanotubes (MWCNTs) and GNPs as an additive on lithium-based grease. The experiments of nanogrease are examined in different values of shear stress, apparent viscosity, temperature and shear rate using Brookfield Programmable Rheometer DV-III ULTRA and characterized by high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD).
Design/methodology/approach
First, GNPs was mixed well with lithium grease using mechanical stirring at 3,500 rpm for 15 min at room temperature to form a homogenous composite at different concentrations (0.5, 1, 1.5, 2 and 2.5 Wt.%). Afterwards, MWCNTs and GNPs are mixed and dispersed well in the lithium grease using a sonication path for 30 min and mechanical stirring at 3,500 rpm for 15 min at 28°C to form a homogenous nanocomposite.
Findings
The results indicated that 1 Wt.% of GNPs is the optimum concentration. Subsequently, the weight percentage of additives varying between MWCNTs and GNPs are tested, and the result indicate that the grease containing GNPs had a 75 per cent increase in shear stress and 93.7 per cent increase in apparent viscosity over ordinary grease.
Originality/value
This work describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.
Keywords
Citation
Ashour, M., Mohamed, A., Elshalakany, A.B., Osman, T. and Khatab, A. (2018), "Rheological behavior of lithium grease with CNTs/GNPs hybrid nanocomposite as an additive", Industrial Lubrication and Tribology, Vol. 70 No. 2, pp. 331-338. https://doi.org/10.1108/ILT-10-2017-0305
Publisher
:Emerald Publishing Limited
Copyright © 2018, Emerald Publishing Limited