L. Rapoport, V. Leshchinsky, M. Lvovsky, O. Nepomnyashchy, Yu Volovik and R. Tenne
In the past few years, inorganic fullerene‐like (IF) supramolecules of metal dichalcogenide WS2 and MoS2 with structures closely related to (nested) carbon fullerenes and…
Abstract
In the past few years, inorganic fullerene‐like (IF) supramolecules of metal dichalcogenide WS2 and MoS2 with structures closely related to (nested) carbon fullerenes and nanotubes have been synthesized. Recent experiments showed that IF added to oil and impregnated into the porous matrixes possess lubricating properties superior to those of layered WS2 and MoS2 (2H platelets). The main goal of this work was to analyze the mechanism of friction of fullerene‐like nanoparticles. Friction and wear behavior of IF in different contact conditions is studied. Third body model is considered. Sliding/rolling of the IF nanoparticles in the boundary of the first bodies and in between the wear particles (third body) is supposed to facilitate the shear of the lubrication film. Broken and oxidized 2H‐WS2 small pieces adhered to wear debris do not provide high tribological properties especially under high loads.
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Manu V. Thottackkad, P.K. Rajendrakumar and K. Prabhakaran Nair
– This manuscript aims to deal with the tribological property variations of engine oil (SAE15W40) by the addition of copper oxide (CuO) nanoparticles on weight percentage basis.
Abstract
Purpose
This manuscript aims to deal with the tribological property variations of engine oil (SAE15W40) by the addition of copper oxide (CuO) nanoparticles on weight percentage basis.
Design/methodology/approach
Experimental studies on the influence of CuO nanoparticles utilised as an additive in lubricating oil (SAE15W40) under boundary lubrication conditions have been carried out using a pin-on-disc machine in accordance with ASTM G-99 standard. The variation of viscosity, coefficient of friction, wear and settling of nanoparticles has been studied as a function of particle concentration in the lubricant.
Findings
Results show that the frictional force and specific wear rate decrease with an increase in concentration of nanoparticles comes to a minimum at a specific concentration and then increases, showing the presence of an optimum concentration. With the increase in concentration of nanoparticles, the kinematic and dynamic viscosities, and the flash and fire points are found to increase.
Originality/value
The use of CuO nanoparticles as additives to a moderate level is a very efficient means of improving the tribological properties of lubricating oils.
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Tatjana Maliar, Satish Achanta, Henrikas Cesiulis and Dirk Drees
The purpose of this paper is to investigate the tribological behaviour of commercially available SAE 10 mineral and rapeseed oils containing Fe particles synthesized directly in…
Abstract
Purpose
The purpose of this paper is to investigate the tribological behaviour of commercially available SAE 10 mineral and rapeseed oils containing Fe particles synthesized directly in the oil phase.
Design/methodology/approach
Sub-micron Fe particles (50-340 nm) were synthesized by wet chemical reduction reaction of FeSO4 by sodium borohydride in the rapeseed and mineral oils in the presence of surfactant: block copolymer (ENB 90R4) or oxyethylated alcohol (OS-20). A four-ball wear tribometer was used to investigate the tribological properties of mineral and rapeseed oil: coefficient of friction (COF), wear scar diameter and wear loss. Viscosity measurements of oil solutions and determination of synthesized Fe particles size were performed as well.
Findings
The presence of Fe particles (0.1 weight per cent) in the rapeseed and mineral oils caused the little change in the COF but resulted in marked improvement of anti-wear property. The oils containing Fe particles with slightly higher viscosity are giving more friction due to viscous drag. The anti-wear enhancement is attributed to the formation of tribofilm and superior load-bearing capability of the modified oil. Both rapeseed and mineral oils irrespective of used surfactant in the presence of 0.1 weight per cent Fe particles (50-140 nm) show sufficiently improved anti-wear properties.
Originality/value
The data collection about tribological behaviour of oils containing Fe particles and various additives in lubricants has a practical interest. The findings could be helpful to increase the knowledge of the behaviour of real tribological systems, where the metallic debris are generated during friction and contaminate the lubricating oil.
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Nanoparticles have been studied as additives to lubrication oils for reducing friction and wear. The purpose of this paper is to investigate the effect of nanofluid on engine oil…
Abstract
Purpose
Nanoparticles have been studied as additives to lubrication oils for reducing friction and wear. The purpose of this paper is to investigate the effect of nanofluid on engine oil and friction reduction in a real engine.
Design/methodology/approach
The nanoparticles were prepared using a high‐temperature arc in a vacuum chamber to vaporize the Ti metal, and then condensed into a dispersant to form the TiO2 nanofluid, which was used as lubricant additive. Experiments were performed in both real engine running and test rig.
Findings
It was found that the engine oil with nanofluid additive with an ethylene glycol dispersant of nanoparticles, had gelled after 10‐h of engine running. The problem of oil gelation (jelly‐like) was solved by replacing the dispersant with paraffin oil. The engine oil with TiO2 nanoparticle additive exhibited lower friction force as compared to the original oil. The experiment showed that a smaller particle size exhibits better friction reduction with particle size ranging from 59 to 220 nm.
Research limitations/implications
The paper is restricted to findings based on the dispersed nanoparticles in fluid as additive for engine lubrication oil.
Practical implications
The test results are useful for the application of nanofluid additive for engine oil.
Originality/value
Most previous researches in this field were executed on tribotester, rather than the actual engine. This paper describes experimental methods and equipment designed to investigate the application of TiO2 nanofluid as lubricant additive in internal combustion engine.
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Jian‐Qiang Hu, Xian‐Yong Wei and Zhi‐Min Zong
Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial…
Abstract
Purpose
Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial seizure load and exhibits certain corrosion, which accelerate oxidation of the lubricant by catalytic effect on metals. The author make efforts to resolve problems said by design a novel thiadiazole complex.
Design/methodology/approach
The complex of thiadiazole dimmer and polyglycol (DMS2‐GL) was synthesized as ashless grease additive. The antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease. Moreover, corrosion inhibiting properties of compositions said was investigated by copper corrosion test.
Findings
The additive DMS2‐GL possessed good load carrying capacity, and exhibits good synergistic antiwear and load carrying prop with rust inhibitor. In addition, dates obtained from copper corrosion test show that it does not corrode copper but coats the metal with a film, and could improve the anticorrosion of corrosive additives molybdenum dialkyldithiophosphate (MoDDP) and molybdenum dibutyldithiocarbamate (MoDTC) by forming protective films on rubbing surface, which contribute to improving corrosion inhibiting property of greases. Finally, the tribo‐chemical mechanism was proposed that thiadiazole dimer and polyglycol could coordinate with each other by polydentate surface interaction, which means thiadiazole rings interact with the metal surface, polyglycol affords a bridging technology linked thiadiazole dimmers so as to lighten loads and strengthen forces between thiadiazole dimmer moleculars.
Originality/value
This paper provides a good ashless additive which has good antiwear, extreme pressure and corrosion inhibiting properties, and fulfils an identified resources need, which can offer practical help in industrial applications and to an individual starting out on an academic career.
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To provide a suitable useful mixing ration of nano‐sized molybdenum disulfide and commercial common molybdenum sulfide (MoS2) particles (approximately 1.5 μm in diameter) in…
Abstract
Purpose
To provide a suitable useful mixing ration of nano‐sized molybdenum disulfide and commercial common molybdenum sulfide (MoS2) particles (approximately 1.5 μm in diameter) in liquid paraffin, which can lead to a better tribological performance.
Design/methodology/approach
The MoS2 nanoparticles and commercial common MoS2 particles (approximately 1.5 μm in diameter) were dispersed in liquid paraffin with different concentrations and ratios by means of ultrasonic in order to study their lubrication capacity, friction reduction and wear resistance. The tribological experiments were carried out by MQ‐800 four‐ball tribometer, in which extreme pressure, wear scan diameter and friction coefficient were measured. It was analyzed that the chemical status of elements on the rubbed surface by X‐ray photoelectron spectroscopy (XPS), and it was observed that the surface topography of wear scan by scanning electron microscope (SEM).
Findings
The results showed that the loading capacity of liquid paraffin with different kinds of MoS2 particles were increased with their contents. The liquid paraffin containing the mixture of MoS2 nanoparticles and common MoS2 particles has a better wear resistance, friction‐reducing performance and extreme pressure property than the liquid paraffin containing pure common MoS2 or pure nano‐MoS2 particles. The optimal mixing ratio of nano‐MoS2 and common MoS2 is 20 wt percent, the loading capacity reaches the highest value. By XPS and SEM it was suggested that the difference in the tribological performance between MoS2 nanoparticles and MoS2 common particles was attributed to the surface and interfacial size‐effect of nanoparticles and the formation of molybdenum trioxide thin film on the rubbed surface.
Research limitations/implications
It is not studied that the effects of mixing of common MoS2 and nano‐MoS2 in the actual lubricating oil with various additives.
Practical implications
It provided a basic research results and data for the application of nano‐MoS2 particles.
Originality/value
The mixing of nanoparticles and non‐nano‐sized particles will lead to new tribological results, which is different from results obtained from other nanoparticles before.
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Laura Peña-Parás, Demófilo Maldonado-Cortés, Jaime Taha-Tijerina, Patricio García-Pineda, Gerardo Tadeo Garza, Mariana Irigoyen, Jorge Gutiérrez and Dario Sánchez
The purpose of this paper is to evaluate the extreme pressure properties of CuO and TiO2 nanoparticle additives with the incorporation of a surfactant within a synthetic fluid for…
Abstract
Purpose
The purpose of this paper is to evaluate the extreme pressure properties of CuO and TiO2 nanoparticle additives with the incorporation of a surfactant within a synthetic fluid for metal-forming applications.
Design/methodology/approach
The paper studies the effect of CuO and TiO2 nanoparticle additives at various concentrations (0.01, 0.05 and 0.10 wt. per cent) in a synthetic lubricant fluid under extreme pressure conditions. Oleic acid surfactant is added to the nanolubricant to improve dispersion and stability of nanoparticles. Extreme pressure tribological tests are performed on a four-ball T-02 tribotester according to the ITEePib Polish method for testing lubricants under conditions of scuffing.
Findings
The results show that the addition CuO and TiO2 nanoparticles under the presence of OA resulted in an increase of the load-carrying capacity (poz) of the lubricant up to 137 and 60 per cent, respectively. The seizure load was also increased by 50 and 15 per cent, respectively.
Practical implications
The results show that CuO and TiO2 nanoparticles can be successfully used as additives improving extreme pressure properties of lubricants.
Originality/value
This demonstrates the potential of nanoparticle additives using surfactants for improving the extreme pressure properties of lubricants. These nanolubricants can be used for metal-forming applications like deep-drawing, achieving an increased tool life.
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Laura Peña-Parás, Patricio García-Pineda, Demófilo Maldonado-Cortés, Gerardo Tadeo Garza and Jaime Taha-Tijerina
The purpose of this work is to investigate the effect of temperature on the extreme-pressure (EP) properties of CuO and TiO2 nanoparticle-filled polymeric lubricants for…
Abstract
Purpose
The purpose of this work is to investigate the effect of temperature on the extreme-pressure (EP) properties of CuO and TiO2 nanoparticle-filled polymeric lubricants for metal-forming processes.
Design/methodology/approach
This paper studies the effect of nanoparticle additives of CuO and TiO2 on the load-carrying capacity of a metal-forming polymer lubricant used for deep-drawing at varying temperatures. EP measurements are performed with a four-ball tribotester according to the ITeE-PIB Polish method for testing lubricants under scuffing conditions. Tests are run at 25, 40, 60 and 75°C to further decrease the lubricant film thickness and determine the effect on the load-carrying capacity and the tribological mechanisms of nanoparticles. The tribological mechanisms of nanoparticles is studied using energy dispersive spectrometry (EDS).
Findings
Results indicate that nanoparticle additives increase the load-carrying capacity of the polymeric lubricant at all concentrations up to 60°C attributed to a mending effect and a reduction in the area of contact of moving surfaces; at 75°C, the improvement is lowered due to nanoparticle re-agglomeration. The best results are found with TiO2 nanoparticles due to their smaller size compared to CuO.
Practical implications
Nanoparticles of CuO and TiO2 are potential EP additives for metal-forming lubricants, providing protection to working components and extending tool life.
Originality/value
These results show the effectiveness and the tribological mechanisms of nanoparticle additives under EP conditions and increasing temperatures found in metal-forming processes.
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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.
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Mustabshirha Gul, Md. Abul Kalam, Nurin Wahidah Mohd Zulkifli, Masjuki Hj. Hassan, Md. Mujtaba Abbas, Sumra Yousuf, Omar Sabah Al-Dahiree, Md. Kamaleldin Gaffar Abbas, Waqar Ahmed and Shahab Imran
The purpose of this study is to improve the tribological characteristics of cotton-biolubricant by adding nanoparticles at extreme pressure (EP) conditions in comparison with…
Abstract
Purpose
The purpose of this study is to improve the tribological characteristics of cotton-biolubricant by adding nanoparticles at extreme pressure (EP) conditions in comparison with commercial lubricant SAE-40.
Design/methodology/approach
This research involved the synthesis of cotton-biolubricant by transesterification process and then the addition of nanoparticles in it to improve anti wear (AW)/EP tribological behavior. SAE-40 was studied as a reference commercial lubricant. AW/EP characteristics of all samples were estimated by the four-ball tribo-tester according to the American Society for Testing and Materials D2783 standard.
Findings
The addition of 1-Wt.% TiO2 and Al2O3 with oleic acid surfactant in cotton-biolubricant decreased wear scar diameter effectively and enhanced the lubricity, load-wear-index, weld-load and flash-temperature-parameters. This investigation revealed that cotton-biolubricant with TiO2 nano-particle additive is more effective and will help in developing new efficient biolubricant to replace petroleum-based lubricants.
Research limitations/implications
Cotton biolubricant with TiO2 nano-particles appeared as an optimistic solution for the global bio-lubricant market.
Originality/value
No one has not studied the cotton biolubricant with nanoparticles for internal combustion engine applications at high temperature and EP conditions.