Tribological and rheological properties of nanorods–Al2O3 as additives in grease

2018 ◽  
Vol 233 (4) ◽  
pp. 605-614 ◽  
Author(s):  
He Qiang ◽  
Tao Wang ◽  
Hongwen Qu ◽  
Yong Zhang ◽  
Anling Li ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Rheological Properties ◽  
Steel Surface ◽  
Wear Scar ◽  
Protective Film ◽  
Wear Scar Diameter ◽  
Lithium Grease ◽  
Rheological Behaviors

In this paper, the tribological and rheological behaviors of nanorods–Al2O3 as an additive in lithium grease at different concentrations were investigated. The morphology of the additive was determined. The improvement in the rheological properties after adding the nanorods was studied and illustrated by measuring the wear of the tested surfaces. The results showed that nanorods–Al2O3 can greatly improve the lubricating effect of grease. The grease with a 0.3 wt% content of nanorods–Al2O3 exhibited the lowest average friction coefficient and wear scar diameter. The worn steel surface was smooth and showed few furrows and grooves. Moreover, a correlation was found between the tribological and rheological properties of lithium grease. By increasing the temperature continuously, a chemical protective film was produced leading to the reduction in the friction coefficient of grease.

Influence of ZrO2 Nanoparticle as Additive on Tribological Property of Lithium Grease

2010 ◽  
Vol 26-28 ◽  
pp. 83-87 ◽  
Author(s):  
Xin Tao Xia ◽  
Ya Ping Zhang ◽  
Yong Zhen Zhang ◽  
Shi Chao Chen
Keyword(s):  
Friction Coefficient ◽  
Tribological Property ◽  
Mass Fraction ◽  
Friction And Wear ◽  
Wear Scar ◽  
Zro2 Nanoparticles ◽  
Wear Scar Diameter ◽  
Lithium Grease ◽  
Mass Fractions

The experiment on the friction and wear of the lithium grease is done by choosing the ZrO2 nanoparticles as the additive in order to study the change of the tribological property of the lithium grease. The friction coefficient decreases by over 30% if the ZrO2 nanoparticles with the mass fractions of 0.25% and 0.5% are used as the additive. The ZrO2 nanoparticles with the mass fraction of 0.25% and 0.5% reach the best result and the wear scar diameter can decrease by 48.8% and 46.5%, respectively.

Frictional Performance of an Ionic Liquid/Graphene Composite Additive in Lubricating Oil

NANO ◽  
2021 ◽  
pp. 2150111
Author(s):  
Shengli You ◽  
Ming Zhou ◽  
Mingyue Wang ◽  
Xin Chen ◽  
Long Jin ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction Pair ◽  
Testing Machine ◽  
Steel Ball ◽  
Wear Scar ◽  
Wear Testing ◽  
Lubricating Oil ◽  
Wear Scar Diameter ◽  
Base Oil ◽  
Frictional Performance

In this study, we used a four-ball friction and wear testing machine to test the tribological properties of [HPy]BF4 ionic liquids (ILs), low-layer graphene (G), and IL and G compounds (IL/G) as lubricant additives at variousconcentrations, loads, and speeds. The morphology of the wear scar was characterized by a white-light interferometer and a scanning electron microscope (SEM). The results showed that the optimal concentrations of IL and G were 0.10[Formula: see text]wt.% and 0.05[Formula: see text]wt.%, respectively. When the IL concentration was 0.10[Formula: see text]wt.%, the friction coefficient and the wear scar diameter (WSD) reduced by approximately 18% and 8%, respectively, compared to the base oil. When the concentration of G was 0.05[Formula: see text]wt.%, the friction coefficient and WSD reduced by approximately 23% and 12%, respectively, compared to the base oil. After adding the optimal concentration of the IL/G composite additive under the same test conditions, the average friction coefficient of the steel ball reduced by approximately 30%, and the average WSD reduced by approximately 18%. IL/G nanoadditives could be easily attached to the pit area on the friction surface of the steel ball, which made the contact surface of the friction pair smoother and the area of the oil film bearing the load larger, compared to those using the base oil. These two combined phenomena promoted synergistic antifriction and antiwear effects, which significantly improved the frictional performance of the base oil.

scholarly journals Effect of nanometer silicon dioxide on the frictional behavior of lubricating grease

2017 ◽  
Vol 7 ◽  
pp. 184798041772593 ◽  
Author(s):  
Qiang He ◽  
Anling Li ◽  
Yachen Guo ◽  
Songfeng Liu ◽  
L-H Kong
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Friction Coefficient ◽  
Silicon Dioxide ◽  
Friction And Wear ◽  
Wear Scar Diameter ◽  
Lithium Grease ◽  
Frictional Behavior ◽  
Scanning Electron ◽  
Base Grease

Nanometer-silicon dioxide encapsulated in lithium grease is prepared, and the frictional behavior of the lithium grease and nanometer-silicon dioxide–contained lithium grease is compared with respect to the additive content, load, and frictional temperature in this article. The structure and morphology of nanometer-silicon dioxide is characterized by X-ray diffraction and scanning electron microscopy, respectively. Friction and wear tests were conducted on a four-ball friction and wear tester. The morphology of worn steel surface is analyzed by scanning electron microscopy and three-dimensional surface profiler. Results show that the addition of nanometer-silicon dioxide in grease can markedly improve the friction-reducing performance and anti-wear ability of base grease. When the nanometer-silicon dioxide in grease is 0.3 wt%, the friction coefficient and wear scar diameter decrease by 26% and 7% compared with base grease, respectively. The nanometer-silicon dioxide (0.3 wt%)–contained grease exhibits the lowest average friction coefficient at the load of 342 N, which decreases by 39% as compared with that of base grease. The worn surface is quite smooth with few shallow furrows and the wear scar diameter decreases under the lubrication of the grease containing 0.3 wt% nanometer-silicon dioxide. Moreover, it was found that the nanometer-silicon dioxide have been incorporated into the surface protective and lubricious layer by energy dispersive spectrometer analysis.

Effect of Soybean Biodiesel Addition on Tribological Performance of Ultra-Low Sulfur Diesel

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Salete Martins Alves ◽  
Aline Cristina Mendes de Farias ◽  
Valdicleide Silva Mello ◽  
José J. Oliveira Junior
Keyword(s):  
Friction Coefficient ◽  
Film Formation ◽  
Physicochemical Characterization ◽  
Protective Film ◽  
Fuel Injector ◽  
Wear Scar Diameter ◽  
Ultra Low Sulfur Diesel ◽  
Soybean Biodiesel ◽  
Low Sulfur ◽  
Low Amplitude

The purpose of this work was to study the influence of soybean biodiesel addition in ultra-low sulfur diesel (ULSD) on its tribological behavior under low-amplitude reciprocating conditions, simulating the operation of a fuel injector system. The methodology was divided into three parts: the first was the fuel preparation and its physicochemical characterization, where were studied four fuels (diesel, soybean biodiesel, and mixtures of them).The following step was the evaluation of the fuel tribological properties, using the high-frequency reciprocating rig (HFRR) test. These tests were carried out by steel ball-on-disk lubricated contact, on which the friction coefficient of friction (COF), the film percentage, and the wear scar diameter (WSD) were measured, according to ASTM D6079-11. In the end, the analysis of the damages presented on the worn disk surfaces was characterized by scanning electronic microscopy (SEM) and atomic force microscopy (AFM) techniques. Results showed that the addition of biodiesel to ULSD is an excellent option to restore the lubricating ability of this fuel. The biodiesel incorporation reduces the friction coefficient and improves the film formation. Besides, the evaluation of worn disk surfaces using SEM and AFM techniques showed that biodiesel avoids damages to surface through protective film formation and reduces the superficial roughness.

scholarly journals Friction Reduction Capabilities of Silicate Compounds Used in an Engine Lubricant on Worn Surfaces

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Devendra Singh ◽  
G. D. Thakre ◽  
L. N. Sivakumar Konathala ◽  
V. V. D. N. Prasad
Keyword(s):  
Friction Coefficient ◽  
Wear Test ◽  
Magnesium Silicate ◽  
Wear Scar ◽  
Friction Reduction ◽  
Elemental Distribution ◽  
Wear Scar Diameter ◽  
Antiwear Properties ◽  
Worn Surfaces

Effects of magnesium silicate and alumina dispersed in engine lubricant on friction, wear, and tribosurface characteristics are studied under boundary and mixed lubrication conditions. Magnesium silicate and alumina, henceforth called as friction reducing compounds (FRC), were dispersed in engine lubricant in very low concentration of 0.01% weight/volume. Four-ball wear test rig was used to assess friction coefficient and wear scar diameter of balls lubricated with and without FRC based engine lubricant. Scanning electron microscopy (SEM) equipped with Energy Dispersive X-ray (EDX) was used to analyse the tribosurface properties and elemental distributions on worn surfaces of the balls. Test results revealed that FRC based engine lubricant increases friction coefficient but marginally reduces wear scar diameter of new balls, whereas, test on the worn-out balls running on FRC based engine lubricants shows 46% reduction in friction coefficient compared to the new balls running on engine lubricants without FRC. Investigations on tribosurfaces with respect to morphology and elemental distribution showed the presence of Si and O elements in micropores of the worn surfaces of the balls, indicating role of FRC in friction coefficient reduction and antiwear properties. These FRC based engine lubricants may be used in the in-use engines.

scholarly journals Preparation and Tribological Properties of Carbon-Coated WS2 Nanosheets

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2835 ◽  
Author(s):  
Zheng Li ◽  
Fanshan Meng ◽  
Haohao Ding ◽  
Wenjian Wang ◽  
Qiyue Liu
Keyword(s):  
Tribological Properties ◽  
Friction And Wear ◽  
Hydrothermal Reaction ◽  
Matrix Material ◽  
Lubricant Additive ◽  
Wear Scar ◽  
Protective Film ◽  
Wear Scar Diameter ◽  
Base Oil ◽  
Carbon Coated

WS2-C is produced from a hydrothermal reaction, in which WS2 nano-sheets are coated with carbon, using glucose as the carbon source. In order to investigate the tribological properties of WS2-C as a lubricant additive, WS2-C was modified by surfactant Span80, and friction tests were carried out on an MRS-10A four-ball friction and wear tester. The results show that Span80 can promote the dispersibility of WS2-C effectively in base oil. Adding an appropriate concentration of WS2-C can improve the anti-wear and anti-friction performance of the base oil. The friction coefficient reached its lowest point upon adding 0.1 wt % WS2-C, reduced by 16.7% compared to the base oil. Meanwhile, the wear scar diameter reached its minimum with 0.15 wt % WS2, decreasing by 26.45%. Moreover, at this concentration, the depth and width of the groove and the surface roughness on the wear scar achieved their minimum. It is concluded that WS2-C dispersed in oil could enter friction pairs to avoid their direct contact, thereby effectively reducing friction and wear. At the same time, WS2-C reacts with the friction matrix material to form a protective film, composed of C, Fe2O3, FeSO4, WO3, and WS2, repairing the worn surface.

Tribological properties of nanometer Al2O3 and nanometer ZnO as additives in lithium-based grease

2018 ◽  
Vol 70 (6) ◽  
pp. 953-960 ◽  
Author(s):  
Qiang He ◽  
Zhigang Wang ◽  
Anling Li ◽  
Yachen Guo ◽  
Songfeng Liu
Keyword(s):  
Tribological Properties ◽  
Wear Scar ◽  
Composite Nanoparticles ◽  
Wear Testing ◽  
Wear Scar Diameter ◽  
Lithium Grease ◽  
Content Type ◽  
Wear And Friction ◽  
Friction Reducing ◽  
Base Grease

Purpose Nanoparticles as the grease additives play an important role in anti-wear and friction-reducing property during the mechanical operation. To improve the lubrication action of grease, the tribological behavior of lithium-based greases with single (nanometer Al2O3 or nanometer ZnO) and composite additives (Al2O3–ZnO nanoparticles) were investigated in this paper. Design/methodology/approach The morphology and microstructure of nanoparticles were characterized by means of transmission electron microscope and X-ray diffraction. Tribological properties of different nanoparticles as additives in lithium-based greases were evaluated using a universal friction and wear testing machine. In addition, the friction coefficient (COF) and wear scar diameter were analyzed. The surface morphology and element overlay of the worn steel surface were analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. Findings The results show that the greases with nanometer Al2O3 or nanometer ZnO and the composite nanoparticles additives both exhibit lower COFs and wear scar diameters than those of base grease. And the grease with Al2O3–ZnO composite nanoparticles possesses much lower COF and shows much better wear resistance than greases with single additives. When the additives contents are 0.4 Wt.% Al2O3 and 0.6 Wt.% ZnO, the composite nanoparticles-based grease exhibits the lowest mean COF (0.04) and wear scar diameter (0.65 mm), which is about 160% and 28% lower than those of base grease, respectively. Originality/value The main innovative thought of this work lies in dealing with the grease using single or composite nanoparticles. And through a serial contrast experiments, the anti-wear and friction-reducing property with different nanoparticles additives in lithium grease are evaluated.

scholarly journals Tribological Properties of Al2O3 Nanoparticles as Lithium Grease Additives

Lubricants ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Ahmed Nabhan ◽  
Ahmed Rashed ◽  
Nouby M. Ghazaly ◽  
Jamil Abdo ◽  
M. Danish Haneef
Keyword(s):  
Tribological Properties ◽  
Wear Scar ◽  
Al2o3 Nanoparticles ◽  
Lithium Grease ◽  
Pin On Disc ◽  
Scar Width

The tribological properties of Lithium grease specimens with different concentrations of Al2O3 nanoparticles were investigated using a pin on disc apparatus under different sliding speeds and normal loads. Results showed that Al2O3 nanoparticles enhanced the tribological properties of lithium grease and reduced the COF and wear scar width by approximately 57.9% and 47.5% respectively.

scholarly journals Comparison Between the Action of Nano-Oxides and Conventional EP Additives in Boundary Lubrication

Lubricants ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 54
Author(s):  
Valdicleide Silva Mello ◽  
Marinalva Ferreira Trajano ◽  
Ana Emilia Diniz Silva Guedes ◽  
Salete Martins Alves
Keyword(s):  
Friction Coefficient ◽  
Boundary Lubrication ◽  
Friction And Wear ◽  
Film Formation ◽  
Environmental Issues ◽  
Protective Film ◽  
Extreme Pressure ◽  
Extreme Pressure Additives ◽  
Environmental Requirements ◽  
Lubrication Conditions

Additives are essential in lubricant development, improving their performance by the formation of a protective film, thus reducing friction and wear. Some such additives are extreme pressure additives. However, due to environmental issues, their use has been questioned because their composition includes sulfur, chlorine, and phosphorus. Nanoparticles have been demonstrated to be a suitable substitute for those additives. This paper aims to make a comparison of the tribological performance of conventional EP additives and oxides nanoparticles (copper and zinc) under boundary lubrication conditions. The additives (nanoparticles, ZDDP, and sulfur) were added to mineral and synthetic oils. The lubricant tribological properties were analyzed in the tribometer HFRR (high frequency reciprocating rig), and during the test, the friction coefficient and percentual of film formation were measured. The wear was analyzed by scanning electron microscopy. The results showed that the conventional EP additives have a good performance owing to their anti-wear and small friction coefficient in both lubricant bases. The oxides nanoparticles, when used as additives, can reduce the friction more effectively than conventional additives, and displayed similar behavior to the extreme pressure additives. Thus, the oxide nanoparticles are more environmentally suitable, and they can replace EP additives adapting the lubricant to current environmental requirements.

scholarly journals Tribochemistry and EP Activity Assessment of Mo-S Complexes in Lithium-Base Greases

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Tarunendr Singh
Keyword(s):  
Electron Spectroscopy ◽  
Auger Electron ◽  
Wear Scar ◽  
Extreme Pressure ◽  
Flash Temperature ◽  
Wear Scar Diameter ◽  
Activity Assessment ◽  
Temperature Parameter ◽  
Ball Test ◽  
Base Grease

The blends of bis(1,5-diaryl-2,4-dithiomalonamido)dioxomolybdenum(VI) complexes in lithium-base grease are evaluated for their extreme pressure activity in a “four-ball test” using 12.7 mm diameter alloy steel ball specimen. The additive, bis(1,5-di-p-methoxyphenyl-2,4-dithiomalonamido)dioxomolybdenum(VI) and bis(1,5-di-p-chloro-phenyl-2,4-dithiomalonamido)dioxomolybdenum(VI) exhibited lower values of wear-scar diameter at higher load and higher values of weld load, flash temperature parameter, and pressure wear index as compared with lithium-base grease without additives. The greases fortified with the developed additives prevent rusting and corrosion of bearings while grease containing no additives did not pass these tests as per the standard tests. These greases have also better oxidation protection as compared to the grease that has no additive. The topography and tribochemistry of the wear-scar surface are carried out by means of scanning electron microscopy and Auger electron spectroscopy techniques, respectively.

Sign in / Sign up

Export Citation Format

Share Document