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Article
Publication date: 10 July 2017

Alaa Mohamed, Mohamed Hamdy, Mohamed Bayoumi and Tarek Osman

This work describes the fabrication of composite nanogrease based on carbon nanotubes (CNTs) as an additive at different volume concentrations 0, 0.5, 1, 2 and 3 Wt.% and…

Abstract

Purpose

This work describes the fabrication of composite nanogrease based on carbon nanotubes (CNTs) as an additive at different volume concentrations 0, 0.5, 1, 2 and 3 Wt.% and investigates the correlation between CNTs and grease rheological behaviour. In addition, study the influence of shear thinning rate at various temperatures and investigates the thermal conductivity of nanogrease. The results demonstrated that grease behaves like a Newtonian viscoelastic material with a narrow linear domain. The thermal conductivity of nanogrease was enhanced by about 31.58 per cent, and the thermal and mechanical stabilities improved. Moreover, the apparent viscosity and dropping point increased by about 93 and 27 per cent, respectively.

Design/methodology/approach

Grease was dissolved in chloroform (10 Wt.%), at 25°C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N,N-dimethylformamide; the dispersion was stirred for 15 min, and then sonicated (40 kHz, 150 W) for 30 min. Grease solution was then added to the CNTs. The nanofluid was magnetically stirred for 15 min and then sonicated for 2 h. This ensured uniform dispersion of nanoparticles in the base fluid.

Findings

Inexpensive and simple fabrication of nanogrease. Thermal conductivity of nanogrease was typically enhanced compared to other reported studies. Apparent viscosity and dropping point increases with the increase the volume concentration.

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.

Details

Industrial Lubrication and Tribology, vol. 69 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 9 April 2018

Alaa Mohamed, Mohamed Hamdy, Mohamed Bayoumi and Tarek Osman

To enhance the tribological properties of nanogrease, one of the new technologies was used to synthesize a nanogrease having carbon nanotubes (CNTs) nanoparticles (NPs…

Abstract

Purpose

To enhance the tribological properties of nanogrease, one of the new technologies was used to synthesize a nanogrease having carbon nanotubes (CNTs) nanoparticles (NPs) with different concentrations. The microstructures of the synthesized NPs were characterized and evaluated by x-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM). Tribological properties of the nanogrease were evaluated using a four-ball tester. The worn surface of four steel balls was investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX).

Design/methodology/approach

Grease was dissolved in chloroform (10 Wt.%), at 25 °C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N, N-dimethylformamide. The mixture was stirred for 15 min and then sonicated (40 kHz, 150 W) for 30 min. After that, the mixture was added to the grease solution and magnetically stirred for 15 min and then sonicated for 2 h.

Findings

The results suggested that CNTs can enhance the antiwear and friction properties of nanogrease at 0.5 Wt.% CNTs to about 57 and 48 per cent, respectively. In addition, the weld load of the base oil containing 0.5 Wt.% CNTs was improved by 17 per cent compared with base grease.

Originality/value

This work describes the inexpensive and simple fabrication of nanogrease for improving the properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Details

Industrial Lubrication and Tribology, vol. 70 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 16 August 2019

Ahmed Mobasher, Alaa Khalil, Medhat Khashaba and Tarek Osman

The purpose of this paper is to evaluate the influence of nanoparticles as an additive on the tribological properties of calcium grease.

Abstract

Purpose

The purpose of this paper is to evaluate the influence of nanoparticles as an additive on the tribological properties of calcium grease.

Design/methodology/approach

The nano additives in this research are with different concentration of multi carbon nanotubes (MWCNTs) and Talc powder (1, 2, 3, 3 and 5 per cent). The ratio of MWCNTs to Talc powder is 1:1. The tribological properties of hyper MWCNTs/Talc powder to calcium grease were evaluated using a pin-on-disk wear testing. The results show that the nano additives MWCNTs/Talc to calcium grease exhibit good performance in anti-wear and friction reduction. The action mechanism was estimated through analysis of the worm surface with x-ray diffraction and transmission electron microscope.

Findings

The result indicates that boundary film mainly composed of MWCNT and Talc powder, and other organic compound was formed on the worm surface during the friction test. In addition, the wear rate and coefficient of friction of nanogreases have shown excellent improvement about 80.62 and 63.44 per cent, respectively, at 4 Wt.% of MWCNTs/Talc powder. Moreover, the thermal conductivity of nanogrease increased about 51.72 per cent.

Originality/value

This study describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Details

Industrial Lubrication and Tribology, vol. 72 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 12 September 2016

Bahaa M. Kamel, Alaa Mohamed, M. El Sherbiny and K.A. Abed

The purpose of this paper is to fabricate composite nanogrease for tribological applications. Multi-walled carbon nanotubes (MWCNTs) with a size 10 nm average diameter and…

Abstract

Purpose

The purpose of this paper is to fabricate composite nanogrease for tribological applications. Multi-walled carbon nanotubes (MWCNTs) with a size 10 nm average diameter and 5 μm in length were used as additives to calcium grease.

Design/methodology/approach

The tribological four-ball machine was used to evaluate calcium grease with carbon nanotubes (CNTs) as an additive. The interaction between CNT and calcium grease (nanogrease) were studied by transmission electron microscopy and X-ray diffraction.

Findings

MWCNTs composite nanogrease was manufactured for tribological applications. The effectiveness of the fabricated grease in improving the tribological performance at different concentrations and under different loads was tested. The results are summarized as follows. CNT nanoparticle additive dispersed in calcium grease significantly improve its anti-wear performance, reducing friction, increasing load-carrying capacity and extreme pressure (EP) property. The friction is reduced by about 50 per cent, the wear scar diameter (WSD) decreased to 32 per cent and the EP properties increases about 38 per cent, with only 3 wt.%. The modified grease with CNTs additives of 3 wt.% showed the most favorable results. Energy dispersive x-ray (EDX) analysis shows that C was present on the worn scar surface, with atomic concentration of about 22 per cent. The presence of C suggests that a lubricating film is likely formed because of the presence of CNTs and very likely prevented the steel-to-steel direct contact.

Originality/value

The results indicated that a 3 wt.% of MWCNT nanogrease is an excellent antiwear, with EP and low friction coefficient. It was also found that the friction coefficient was reduced to about 50 per cent, the WSD decreased by about 32 per cent and the EP properties increased about 38 per cent. The mating surfaces were investigated with scanning electron microscopy and EDX. The results show that a boundary film mainly composed of CNTs, Cr and Fe was formed on the rubbed surfaces.

Details

Industrial Lubrication and Tribology, vol. 68 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 12 March 2018

Mohamed Ashour, Alaa Mohamed, Abou Bakr Elshalakany, Tarek Osman and Aly Khatab

The purpose of this paper is to investigate the rheological characteristics of graphene nanoplatelets (GNPs) and hybridized nanocomposite consisting of multi-walled carbon…

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.

Details

Industrial Lubrication and Tribology, vol. 70 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Content available
Article
Publication date: 9 April 2018

Carsten Gachot

Abstract

Details

Industrial Lubrication and Tribology, vol. 70 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 9 April 2018

Shanhua Qian, Hongyue Wang, Chuanhui Huang and Yongwu Zhao

This paper aims to modify carbon nanotubes with oleic acid, and to study the tribological properties of castor oil with modified carbon nanotubes additives. The proper…

Abstract

Purpose

This paper aims to modify carbon nanotubes with oleic acid, and to study the tribological properties of castor oil with modified carbon nanotubes additives. The proper additives are sought for the future engineering application of castor oil.

Design/methodology/approach

Tribological properties of the castor oils mixed with the modified carbon nanotubes of four mass percentages were investigated using a four-ball testing rig. Coefficient of friction and wear scar diameter were obtained in each test, and the mechanism of modified carbon nanotubes and castor oil was discussed.

Findings

The results indicated that modified carbon nanotubes had better dispersion in castor oil. Coefficient of friction first increased, then decreased and finally grew stable with the time, and wear scar diameter of steel surface functioned as a first reduced then increased change with the additive mass percentage of modified carbon nanotubes. The minimum of average coefficient of friction and wear scar diameter occurred at 0.02 Wt.% modified carbon nanotubes.

Originality/value

A small amount of modified carbon nanotubes could improve properties of the castor oil, and the mixed castor oil with 0.02 Wt.% modified carbon nanotubes would be most possibly used in engineering applications.

Details

Industrial Lubrication and Tribology, vol. 70 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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