Rheological behavior of lithium grease with CNTs/GNPs hybrid nanocomposite as an additive. Issue 2 (12th March 2018)

• Record Type: Journal Article
• Authors: Ashour, Mohamed; Mohamed, Alaa; Elshalakany, Abou Bakr; Osman, Tarek; Khatab, Aly
• Is Part Of: Industrial lubrication and tribology. Volume 70:Issue 2(2018)
• Page Start: 331
• Page End: 338
• Publication Date: 2018-03-12
• Subjects: Carbon nanotubes -- Grease -- Rheology -- Nanocomposite -- Graphene nanoplatelets; Lubrication and lubricants -- Periodicals; Tribology -- Periodicals; 621.89
• DOI: 10.1108/ILT-10-2017-0305
• Languages: English
• ISSNs: 0036-8792

Abstract

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.