Modified graphene as novel lubricating additive with high dispersion stability in oil

Abstract Graphene is a promising material as a lubricant additive for reducing friction and wear. Here, a dispersing method which combines chemical modification of graphene by octadecylamine and dicyclohexylcarbodiimide with a kind of effective dispersant has been successfully developed to achieve the remarkable dispersion stability of graphene in base oil. The stable dispersion time of modified graphene (0.5 wt%) with dispersant (1 wt%) in PAO-6 could be up to about 120 days, which was the longest time reported so far. At the same time, the lubricant exhibits a significant improvement of tribological performance for a steel ball to plate tribo-system with a normal load of 2 N. The coefficient of friction between sliding surfaces was ~0.10 and the depth of wear track on plate was ~21 nm, which decreased by about 44% and 90% when compared to pure PAO-6, respectively. Furthermore, the analysis of the lubricating mechanisms in regard to the sliding-induced formation of nanostructured tribo-film has been contacted by using Raman spectra and TEM.

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Tribological Behavior of Lamellar Molybdenum Trioxide as a Lubricant Additive

Materials ◽

10.3390/ma11122427 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2427 ◽

Cited By ~ 7

Author(s):

Wei Tang ◽

Rui Liu ◽

Xiangyong Lu ◽

Shaogang Zhang ◽

Songyong Liu

Keyword(s):

Friction And Wear ◽

Molybdenum Trioxide ◽

Tribological Behavior ◽

Normal Load ◽

Lubricant Additive ◽

Base Oil ◽

Reducing Ability ◽

Wear Reduction ◽

Friction Reducing ◽

Friction And Wear Tests

In this study, the tribological behavior of lamellar MoO3 as a lubricant additive was investigated under different concentrations, particle sizes, normal loads, velocity, and temperature. The friction and wear tests were performed using a tribometer and with a reciprocating motion. The results indicate that the friction-reducing ability and antiwear property of the base oil can be improved effectively with the addition of lamellar MoO3. The 0.5 wt % and 0.1 wt % concentrations of MoO3 yield the best antifriction and antiwear effects, respectively. The maximum friction and wear reduction is 19.8% and 55.9%, compared with that of the base oil. It is also found the MoO3 additive can decrease the friction considerably under a high velocity and normal load, and increase the working temperature. The smaller the size of MoO3, the better the friction-reducing effect the lamellar MoO3 shows. The friction-reducing and antiwear mechanisms of lamellar MoO3 were discussed.

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Nanodiamond Particles as Secondary Additive for Polyalphaolefin Oil Lubrication of Steel–Aluminium Contact

Nanomaterials ◽

10.3390/nano11061438 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1438

Author(s):

Ankush Raina ◽

Mir Irfan Ul Haq ◽

Ankush Anand ◽

Sanjay Mohan ◽

Rajiv Kumar ◽

...

Keyword(s):

Coefficient Of Friction ◽

Hexagonal Boron Nitride ◽

Normal Load ◽

Lubricant Additive ◽

Oil Lubrication ◽

Volumetric Wear ◽

Base Oil ◽

Applied Normal Load ◽

Lubrication Performance ◽

The Coefficient Of Friction

Nanodiamond (ND) particles are effective lubricant additives. Attention of research has shifted towards investigating the particles as secondary additives. ND particles provide more benefits as secondary additives than as the sole lubricant additive for steel–steel contacts. In this work, the influence of ND particles as secondary additives on oil lubrication of steel–aluminium tribopair (hard–soft contact) was examined. AISI 52100 steel balls were slid against AA2024 aluminium alloy discs, in the presence of polyalphaolefin (PAO) base oil, in boundary lubrication regime (applied normal load: 10 N to 50 N). Primary additives were copper oxide (CuO) and hexagonal boron nitride (h-BN) nanoparticles. The addition of ND particles to PAO, with CuO and h-BN as primary additives, at the lowest applied normal load of 10 N: (i) decreased the volumetric wear of the aluminium discs by 28% and 63%, respectively, and (ii) decreased the coefficient of friction by 15% and 33%, respectively. At the highest applied normal load of 50 N, it: (i) decreased the volumetric wear of the aluminium discs by 20% and 38%, respectively, and (ii) decreased the coefficient of friction by 5.4% and 8%, respectively. ND particles as secondary additives significantly reduce energy loss and power loss as a consequence of an effective reduction in friction during sliding. Unique characteristics of ND particles—such as their (a) physicochemical and thermal properties, (b) ball bearing and polishing effects and (c) synergistic interaction with primary additives to form stable tribofilms—enhance the lubrication performance of steel–aluminium contact. ND particles in combination with h-BN nanoparticles showed the best performance, due to better synergy between the primary additive and the secondary additive. Results from the investigation indicate that ND particles taken as secondary additives in small amount (0.2 wt%) can improve oil lubrication performance of hard–soft contacts in engineering systems.

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Dispersion Stability And Tribological Properties of Covalently Modified Graphene As A Lubricating Oil Additive

10.21203/rs.3.rs-645776/v1 ◽

2021 ◽

Author(s):

Mingyue Wang ◽

Ming Zhou ◽

Shengli You ◽

Xin Chen ◽

Youtang Mo ◽

...

Keyword(s):

Friction And Wear ◽

Covalent Modification ◽

Dispersion Stability ◽

Lubricating Oil ◽

Primary Amines ◽

Base Oil ◽

Amide Bonds ◽

Stable Dispersion ◽

Wide Range ◽

Modified Graphene

Abstract Graphene has excellent mechanical properties with a low coefficient of friction and wear resistance and has a wide range of tribological applications. However, the stable dispersion of graphene in lubricating media is challenging. In this study, graphene is processed via covalent modification. A mild oxidation method selectively grafts carboxyl groups on the edge of the graphene sheet, before connecting tertiary alkyl primary amines through amide bonds. The alkyl chain allows graphene to be stably dispersed in hydrocarbon solvents.. FT-IR, XPS, Raman, XRD, SEM, etc. are used to characterize the covalently modified graphene (MG). Dispersion stability experiments showed that MG exhibited stable dispersion in 500N base oil and 15w-40 commercial lubricants, with stability for over 2 months. Tribological test results show that MG in 500N and 15w-40 significantly reduces the friction and wear of steel-steel friction pairs. The stable dispersion of MG in lubricating oil enables the formation of a stable chemical reaction film and graphene physical deposition film during the friction, protects the worn surface, and reduces direct contact, thereby significantly reducing friction and wear.

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Evaluation of Friction and Wear Behavior of Date Palm Fruit Syrup as an Environmentally Friendly Lubricant

Materials ◽

10.3390/ma12101589 ◽

2019 ◽

Vol 12 (10) ◽

pp. 1589 ◽

Cited By ~ 1

Author(s):

Mazin Tahir ◽

Abdul Samad Mohammed ◽

Umar Azam Muhammad

Keyword(s):

Tribological Properties ◽

Friction And Wear ◽

Date Palm ◽

Wear Behavior ◽

Normal Load ◽

Environmentally Friendly ◽

Potential Candidate ◽

Palm Fruit ◽

Wear Rates ◽

The Coefficient Of Friction

The effect of various operational factors, such as sliding speed, normal load and temperature on the tribological properties of Date palm fruit syrup (DPFS) as an environmentally friendly lubricant, is investigated. Ball-on-disc wear tests are conducted on mild steel samples in the presence of DPFS as a lubricant under different conditions and the coefficient of friction and wear rate are measured. Scanning electron microscopy, stylus profilometry, and Fourier transform infrared spectroscopy are used to evaluate the wear tracks to determine the underlying wear mechanisms. Results showed that DPFS has excellent tribological properties in terms of low friction and low wear rates making it a potential candidate to be used as a lubricant in tribological applications.

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Variations in strain affect friction and microstructure evolution in copper under a reciprocating tribological load

Journal of Materials Research ◽

10.1557/s43578-020-00050-z ◽

2021 ◽

Author(s):

Sarah Becker ◽

Katrin Schulz ◽

Dennis Scherhaufer ◽

Peter Gumbsch ◽

Christian Greiner

Keyword(s):

Microstructure Evolution ◽

Strain Distribution ◽

Friction And Wear ◽

Frictional Contact ◽

Tribological Performance ◽

Micro Milling ◽

Sample Length ◽

Entire Sample ◽

The Coefficient Of Friction ◽

Membrane Stiffness

Abstract The microstructure of the materials constituting a metallic frictional contact strongly influences tribological performance. Being able to tailor friction and wear is challenging due to the complex microstructure evolution associated with tribological loading. Here, we investigate the effect of the strain distribution on these processes. High-purity copper plates were morphologically surface textured with two parallel rectangles—referred to as membranes—over the entire sample length by micro-milling. By keeping the width of these membranes constant and only varying their height, reciprocating tribological loading against sapphire discs resulted in different elastic and plastic strains. Finite element simulations were carried out to evaluate the strain distribution in the membranes. It was found that the maximum elastic strain increases with decreasing membrane stiffness. The coefficient of friction decreases with increasing membrane aspect ratio. By analyzing the microstructure and local crystallographic orientation, we found that both show less change with decreasing membrane stiffness. Graphic abstract

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Neat Ionic Liquids and Additives in Lubrication of Steel-Aluminum

World Tribology Congress III, Volume 1 ◽

10.1115/wtc2005-63120 ◽

2005 ◽

Cited By ~ 1

Author(s):

A. E. Jimenez ◽

M. D. Bermudez ◽

P. Iglesias ◽

F. J. Carrion ◽

G. Martinez-Nicolas

Keyword(s):

Ionic Liquids ◽

Friction And Wear ◽

Room Temperature ◽

Normal Load ◽

Room Temperature Ionic Liquids ◽

Contact Conditions ◽

Base Oil ◽

Wear Rates ◽

Oil Additives ◽

Tribochemical Processes

A series of seven room-temperature ionic liquids (IL) have been studied as neat and 1 wt% base oil additives in the lubrication of steel and aluminum contacts under increasing sliding speed, normal load and temperature. IL used as neat lubricants can produce, depending on the composition, tribochemical processes at the aluminum-steel interface associated with an increase in friction coefficients and wear rates. When IL are used as 1 wt% additives, surfaces interactions can give friction and wear values lower than those obtained for the neat IL. The lubricating performance of the additives is more dependent on contact conditions than on composition.

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Nano Serpentine Powders as Lubricant Additive: Tribological Behaviors and Self-Repairing Performance on Worn Surface

Nanomaterials ◽

10.3390/nano10050922 ◽

2020 ◽

Vol 10 (5) ◽

pp. 922 ◽

Cited By ~ 2

Author(s):

Binbin Wang ◽

Zhaodong Zhong ◽

Han Qiu ◽

Dexin Chen ◽

Wei Li ◽

...

Keyword(s):

Dynamic Balance ◽

Liquid Paraffin ◽

Lubricant Additive ◽

Tribological Performance ◽

Wear Scar Diameter ◽

Base Oil ◽

Steel Balls ◽

Worn Surface ◽

Friction And Wear Characteristics

Natural serpentine powders are applicable as additives for various lubricating oils. However, no uniform theories explain their tribological performance, lubrication, and wear mechanism, especially their self-repairing mechanism. Herein, the influence of different nano serpentine powders (NSPs) contents in liquid paraffin on the friction and wear characteristics of steel balls and the self-repairing process of NSPs on the worn surface were studied. Results show that the optimal amount of NSPs was 0.5 wt %. Relative to those of the base oil, the friction coefficients and wear spot diameters were reduced by 22.8% and 34.2%, respectively. Moreover, the long-term tribological test shows that the wear scar diameter decreased slightly after 3 h, reaching the state of dynamic balance between wear and repair. The outstanding tribological performance should be attributed to the formed bilayer tribofilm, the first layer of which contains nanoparticles surrounded by lubricants and the second layer of which contains nanoparticles compacted onto the surface of the steel ball.

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The Effect of Surface Texture on Lubricated Fretting

Materials ◽

10.3390/ma13214886 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4886

Author(s):

Agnieszka Lenart ◽

Pawel Pawlus ◽

Andrzej Dzierwa ◽

Slawomir Wos ◽

Rafal Reizer

Keyword(s):

Coefficient Of Friction ◽

Surface Texture ◽

Friction And Wear ◽

Normal Load ◽

Disc Surface ◽

The Coefficient Of Friction ◽

42Crmo4 Steel ◽

Ball Diameter ◽

Steel Balls ◽

Effect Of Surface

Experiments were conducted using an Optimol SRV5 tester in lubricated friction conditions. Steel balls from 100Cr6 material of 60 HRC hardness were placed in contact with 42CrMo4 steel discs of 47 HRC hardness and diversified surface textures. Tests were carried out at a 25–40% relative humidity. The ball diameter was 10 mm, the amplitude of oscillations was set to 0.1 mm, and the frequency was set to 80 Hz. Tests were performed at smaller (45 N) and higher (100 N) normal loads and at smaller (30 °C) and higher (90 °C) temperatures. During each test, the normal load and temperature were kept constant. We found that the disc surface texture had significant effects on the friction and wear under lubricated conditions. When a lower normal load was applied, the coefficient of friction and wear volumes were smaller for bigger disc surface heights. However, for a larger normal load a higher roughness corresponded to a larger coefficient of friction.

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Tribological Performance of Nanocomposite Carbon Lubricant Additive

Materials ◽

10.3390/ma12010149 ◽

2019 ◽

Vol 12 (1) ◽

pp. 149 ◽

Cited By ~ 2

Author(s):

Chuanyi Xue ◽

Shouren Wang ◽

Daosheng Wen ◽

Gaoqi Wang ◽

Yong Wang

Keyword(s):

Friction And Wear ◽

Frictional Contact ◽

Adhesive Wear ◽

Friction Pair ◽

Lubricant Additive ◽

Suspension Stability ◽

Wear Performance ◽

Base Oil ◽

Test Conditions ◽

Friction And Wear Characteristics

In this research, nanocomposite carbon has been found to have excellent tribological properties as a lubricant additive. To reduce high friction and wear in friction pairs, the modified nanocomposite carbon has been prepared for chemical technology. The morphology and microstructure of the modified nanocomposite carbon were investigated via TEM, SEM, EDS, XPS, and Raman. In this study, varying concentrations (1, 3, and 5 wt. %) within the modified nanocomposite carbon were dispersed at 350 SN lubricant for base oil. The suspension stability of lubricating oils with the modified nanocomposite carbon was determined by ultraviolet-visible light (UV-VIS) spectrophotometry. The friction and wear characteristics of lubricants containing materials of the modified nanocomposite carbon were evaluated under reciprocating test conditions to simulate contact. The morphology and microstructure of the friction pair tribofilms produced during frictional contact were investigated via SEM, EDS, and a 3D surface profiler. The results showed that scratches, pits, grooves, and adhesive wear were significantly reduced on the surface of the friction pair which was used with 3% nanocomposite carbon lubricant. Additionally, the modified nanocomposite carbon showed excellent friction reducing and anti-wear performance, with great potential for the application of anti-wear.

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