Tribological behaviour of calcium grease containing carbon nanotubes additives

2016 ◽  
Vol 68 (6) ◽  
pp. 723-728 ◽  
Author(s):  
Bahaa M. Kamel ◽  
Alaa Mohamed ◽  
M. El Sherbiny ◽  
K.A. Abed
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Friction Coefficient ◽  
Average Diameter ◽  
Tribological Behaviour ◽  
Wear Scar Diameter ◽  
Content Type ◽  
X Ray ◽  
Lubricating Film ◽  
Multi Walled Carbon Nanotubes

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.

Synthesis and Characteristics of Hierarchical Nanostructure Fe3O4 Coated Multi-Walled Carbon Nanotubes

2014 ◽  
Vol 926-930 ◽  
pp. 258-261
Author(s):  
Jing Heng Deng ◽  
Kan Ping Yu ◽  
Jian Guo Xie
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Solvothermal Process ◽  
X Ray ◽  
Hierarchical Nanostructure ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Hierarchical nanostructure Fe3O4/multi-walled carbon nanotubes (Fe3O4/MWCNTs) were prepared by solvothermal process using acid treated MWCNTs and iron acetylacetonate in ethylene glycol as reduction reagent. The materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). The results showed that petal-like hierarchical Fe3O4 grew on MWCNTs and the Fe3O4 nanoparticles had diameters in the range of 55-110 nm. It was a facile approach to grow hierarchical nanoFe3O4.

Tribological behaviour of graphene oxide sheets as lubricating additives in bio-oil

2018 ◽  
Vol 70 (8) ◽  
pp. 1396-1401 ◽  
Author(s):  
Daoyi Wu ◽  
Yufu Xu ◽  
Lulu Yao ◽  
Tao You ◽  
Xianguo Hu
Keyword(s):  
Graphene Oxide ◽  
Friction Coefficient ◽  
Wear Loss ◽  
Tribological Behaviour ◽  
Low Friction ◽  
Content Type ◽  
Base Oil ◽  
Lubricating Film ◽  
Bio Oil ◽  
Practical Implications

Purpose This paper aims to study the upgradation of the lubricating performance of the renewable base oil , and to study the tribological behavior of graphene oxide (GO) sheets used as lubricating additives in bio-oil for iron/steel contact. Design/methodology/approach A multifunctional end-face tribometer was used to characterize the friction coefficient and wear loss of the tribosystem under different lubricants. Findings The experimental results show that GO sheets with small size benefit lubricating effects and the optimal concentration of GO sheets in bio-oil is 0.4-0.6 per cent, which can form a complete lubricating film on the frictional interfaces and obtain a low friction coefficient and wear loss. Higher concentration of GO sheets can result in a significant aggregation of the sheets, reducing the content of the lubricating components in the bio-oil, which results in the increase in friction and wear; at this stage, the main wear pattern was ascribed to adhesive wear. Practical implications These results show a promising prospect of improving the tribological performance of renewable base oil with the introduction of GO sheets as additives. Originality/value No literature has covered the tribological behaviour of GO sheets in bio-oil. This study contributes to accelerating the application of bio-oil.

A simple method to prepare carbon nanotubes from sunflower seed hulls and sago and their application in supercapacitor

2015 ◽  
Vol 44 (1) ◽  
pp. 7-12 ◽  
Author(s):  
H.Y. Zhang ◽  
H.J. Niu ◽  
Y.M. Wang ◽  
C. Wang ◽  
X.D. Bai, ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Sunflower Seed ◽  
Electrochemical Impedance ◽  
Cyclic Voltammograms ◽  
Production Scale ◽  
Simple Method ◽  
Content Type ◽  
X Ray

Purpose – The purpose of this paper was to provide a simple method for the preparation of carbon nanotubes (CNTs) by pyrolysing sunflower seed hulls and sago and to evaluate the application of such CNTs in supercapacitors. Design/methodology/approach – The CNTs were obtained by pyrolysing sunflower seed hulls and sago at 800°C. The prepared CNTs were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammograms, galvanostatic charge and discharge and electrochemical impedance spectra methods. Findings – The CNTs had large surface areas as determined by the methylene blue method and the Brunauer – Emmett – Teller method. And the CNTs that were prepared by pyrolysing the natural sunflower seed hulls (denoted as CNTs-1) and sago (denoted as CNTs-2) had capacitances of 86.9 F/g and 26.7 F/g, respectively. Research limitations/implications – The capacitances of CNTs can be further improved. Practical implications – The exceptional electronic and mechanical properties of CNTs prepared lend the CNTs to diverse applications including electrocatalysts, hydrogen storage, photovoltaic devices actuators, energy storage, field-emitting flat panel displays and composites. Originality/value – Currently, CNTs have not yet been used in the industry at a mass production scale due to high costs associated. The outcomes of the study reported in this article could provide a convenient method in aid of industrialisation of the production of CNTs.

scholarly journals Модификация смачиваемости углеродных нанотрубок с помощью ионного облучения

2019 ◽  
Vol 53 (12) ◽  
pp. 1692
Author(s):  
А.И. Морковкин ◽  
Е.А. Воробьева ◽  
А.П. Евсеев ◽  
Ю.В. Балакшин ◽  
А.А. Шемухин
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ion Beam ◽  
Average Diameter ◽  
Distilled Water ◽  
X Ray ◽  
Ion Beam Modification ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This paper presents the results of experiment to change wettability of commercial multi-walled carbon nanotubes (MWCNTs) Taunit-MD after irradiation with 120 keV Ar+ ions with various fluences. Using the Raman spectroscopy and scanning electron microscopy, the structure of the irradiated MWCNTs was investigated and X-ray microanalysis was carried out. The dependences of the average diameter of the MWCNTs, the concentration of O2 in the samples, and the defectiveness of the MWCNTs on the irradiation fluence, as well as their effect on the wettability angle with distilled water, ethylene glycol and cyclohexane are considered. The possibility and prospects of using ion-beam modification methods for the controlled change of the wetting angle in order to create a hydrophobic or hydrophilic MWCNTs coating to various types of liquids are discussed.

scholarly journals Hybrid Materials Based on Multi-Walled Carbon Nanotubes and Nanoparticles with Antimicrobial Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1415
Author(s):  
Madalina Elena David ◽  
Rodica-Mariana Ion ◽  
Ramona Marina Grigorescu ◽  
Lorena Iancu ◽  
Alina Maria Holban ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Antimicrobial Activity ◽  
Hybrid Materials ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Ag Nps ◽  
X Ray ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this study, multi-walled carbon nanotubes (MWCNTs) were decorated with different types of nanoparticles (NPs) in order to obtain hybrid materials with improved antimicrobial activity. Structural and morphological analysis, such as Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, environmental scanning electron microscopy/energy-dispersive X-ray spectroscopy and the Brunauer–Emmett–Teller technique were used in order to investigate the decoration of the nanotubes with NPs. Analysis of the decorated nanotubes showed a narrow size distribution of NPs, 7–13 nm for the nanotubes decorated with zinc oxide (ZnO) NPs, 15–33 nm for the nanotubes decorated with silver (Ag) NPs and 20–35 nm for the nanotubes decorated with hydroxyapatite (HAp) NPs, respectively. The dispersion in water of the obtained nanomaterials was improved for all the decorated MWCNTs, as revealed by the relative absorbance variation in time of the water-dispersed nanomaterials. The obtained nanomaterials showed a good antimicrobial activity; however, the presence of the NPs on the surface of MWCNTs improved the nanocomposites’ activity. The presence of ZnO and Ag nanoparticles enhanced the antimicrobial properties of the material, in clinically relevant microbial strains. Our data proves that such composite nanomaterials are efficient antimicrobial agents, suitable for the therapy of severe infection and biofilms.

Synthesis and Characterization of Silver Coated Multi Walled Carbon Nanotubes for Dye Degradation in Textile Waste Water

2018 ◽  
Vol 24 (8) ◽  
pp. 5677-5680
Author(s):  
C Shilpa ◽  
N Pradeep ◽  
V Uma
Keyword(s):  
Waste Water ◽  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Dye Degradation ◽  
Textile Waste ◽  
X Ray ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Textile Waste Water ◽  
Scanning Electron

The most important challenge across the globe in recent years is to meet the sufficient supply of drinking water and to reduce water pollution, one of the major problems is the waste water from the textile industry and the purification of dye based water is a challenge for many years. In this paper we report dye degradation in textile waste water using Ag coated MWCNTs. Multi walled carbon nanotubes were synthesized using chemical vapor deposition method, using powder catalyst and the coating of Silver in MWCNTs was done by wet chemical method. Three Different silver concentrations were taken for coating the MWCNT. These Ag coated Multiwall carbon nanotubes were characterized by X-ray Diffraction, Field Emission Scanning Electron Microscopy (FESEM) and UV spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) was used to study the morphology of the sample and Energy dispersive X-ray analysis (EDAX) characterization was done to study the chemical composition. The multiwalled carbon nanotubes act like a absorbent which helps in dye degradation and silver has antibacterial properties which help in removing the bacteria and viruses in water. The adsorption was tested for three different samples of Ag coated MWCNT’s using photocatalytic study. The UV intensity peaks showing the observable shift in intensity. Adsorption column test was done, using the Ag coated MWCNTs, using dye based water appears clear after the test.

scholarly journals Carbide Nanoparticles Encapsulated in the Caves of Carbon Nanotubes by an In Situ Reduction-Carbonization Route

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Chunli Guo ◽  
Yitai Qian ◽  
Pengju Han
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Average Diameter ◽  
Structural Features ◽  
Metal Catalyst ◽  
In Situ Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Carbides (TiC, WC, and NbC) nanoparticles fully encapsulated in the caves of carbon nanotubes (CNTs) were synthesized via an in situ reduction-carbonization route at 600∘C in an autoclave. The structural features and morphologies of as-obtained products were investigated using by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy (HRTEM). HRTEM studies showed that the average diameter of CNTs encapsulated with carbide nanoparticles are in the range of 15–40 nm. The reaction temperature, the reaction time, and the metal catalyst are found to play crucial roles to the product morphology. The growth mechanism of carbide nanoparticles encapsulated in CNTs was discussed in detail.

scholarly journals Comparison between multi-walled carbon nanotubes and titanium dioxide nanoparticles as additives on performance of turbine meter oil nano lubricant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hadi Pourpasha ◽  
Saeed Zeinali Heris ◽  
Yaghob Mohammadfam
Keyword(s):  
Carbon Nanotubes ◽  
Titanium Dioxide ◽  
Friction Coefficient ◽  
Pressure Drop ◽  
Mass Fraction ◽  
Viscosity Index ◽  
Wear Depth ◽  
Nano Lubricant ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractThis research aims of compare the impact of the mass fraction of multi-walled carbon nanotubes (MWCNTs) and titanium dioxide (TiO2) nano additive on the tribological and thermophysical attributes of turbine meter oil. These attributes include the average friction coefficient, pressure drop, wear, flash point, pour point, relative viscosity, kinematics viscosity, and viscosity index. The pressure drops and the average friction coefficient inside the copper tube were simulated and compared with experimental results. In this study, for the synthesis of nano lubricants from turbine meter oil as a pure fluid and from MWCNTs and TiO2 as nano additives in the mass fraction of 0.05, 0.1, 0.2, 0.3, and 0.4 wt.% and from oleic acid and Triton x100 as surfactants were utilized. The results illustrated that the wear depth of copper pins in the presence of nano lubricant with 0.4 wt.% of MWCNTs and 0.1 wt.% TiO2 was improved by 88.26% and 71.43%, respectively. Increasing 0.3 wt.% of TiO2 and MWCNTs into the oil caused to improvement in viscosity index. The simulation data and experimental data for the pressure drop were closer together and indicated a minor error that the maximum error is less than 10%.

scholarly journals Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Jung-Eun Park ◽  
Yong-Seok Jang ◽  
Tae-Sung Bae ◽  
Min-Ho Lee
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Sol Gel ◽  
Pure Titanium ◽  
Cell Proliferation And Differentiation ◽  
Transmission Electron ◽  
Proliferation And Differentiation ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

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