Boundary Lubricants with Exceptionally Low Friction Coefficients Based on 2D Close-Packed Phosphatidylcholine Liposomes

2011 ◽  
Vol 23 (31) ◽  
pp. 3517-3521 ◽  
Author(s):  
Ronit Goldberg ◽  
Avi Schroeder ◽  
Gilad Silbert ◽  
Keren Turjeman ◽  
Yechezkel Barenholz ◽  
...  
Keyword(s):  
Low Friction ◽  
Friction Coefficients ◽  
Phosphatidylcholine Liposomes ◽  
Boundary Lubricants

Low-friction mechanism of silicon carbide and cemented carbide in water

2020 ◽  
pp. 135065012092868
Author(s):  
Fei Guo ◽  
Fan Wu ◽  
Fangyong Wu ◽  
Yuming Wang
Keyword(s):  
Silicon Carbide ◽  
Tribological Properties ◽  
Rotation Speed ◽  
Hydrodynamic Lubrication ◽  
Cemented Carbide ◽  
Matched Pairs ◽  
Low Friction ◽  
Friction Mechanism ◽  
Friction Coefficients ◽  
Test Conditions

The tribological properties of self-mated silicon carbide, self-mated cemented carbide, and cemented carbide/silicon carbide under water lubrication were studied. The three matched pairs could achieve low-friction coefficients (0.01–0.03) under certain test conditions. Additionally, the dependence of the friction coefficients on the rotation speed and load were measured. By combining these results with the observed surface topography and wear measurements, it was determined that the three matched pairs were in the hydrodynamic lubrication. In addition, combined with experiments in ethylene glycol and PAO40, it was shown that the actual viscosity of the lubricant had a significant influence on the realization of low friction. Furthermore, matching materials had an influence on the tribological properties, which may be related to the surface wettability of the lubricant.

scholarly journals Evaluation of Friction Behavior and Surface Interactions of Cyano-Based Ionic Liquids under Different Sliding Contacts and High Vacuum Condition

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 69 ◽  
Author(s):  
Shouhei Kawada ◽  
Seiya Watanabe ◽  
Shinya Sasaki ◽  
Masaaki Miyatake
Keyword(s):  
Mass Spectrometry ◽  
Ionic Liquids ◽  
High Vacuum ◽  
Mass Spectrometry Analysis ◽  
Low Friction ◽  
Friction Behavior ◽  
Friction Coefficients ◽  
Spectrometry Analysis ◽  
Worn Surface ◽  
Nascent Surface

The friction coefficients of ionic liquids were evaluated by many investigations. Most investigations used fluorine-based ionic liquids as lubricants. However, these ionic liquids produce the corrosion wear. This investigation focuses on the use of cyano-based ionic liquids as lubricants. Compared to fluorine-based ionic liquids, cyano-based ionic liquids exhibit high friction coefficients against steel material. This work examines how the friction coefficients of cyano-based ionic liquids are influenced by the type of sliding material used (AISI 52100, TiO2, and tetrahedral amorphous carbon). TiO2 lubricated with 1-ethyl-3-methylimidazolium tricyanomethanide, and ta-C lubricated with 1-butyl-1methylpyrrolidinium tetracyanoborate exhibited very low friction coefficients, smaller than fluorine-based ionic liquids. Time-of-Flight Secondary Ion Mass Spectrometry analysis showed that anions adsorb onto the worn surface, suggesting that anion adsorption is a critical parameter influencing friction coefficients. Quadrupole Mass Spectrometry measurements revealed that cations decompose on the nascent surface, preventing adsorption on the worn surface. These results suggest that low friction coefficients require the decomposition of cations and adsorption of anions. The reactivity of nascent surface changes with the sliding material used due to varying catalytic activity of the nascent surfaces.

Stochastic Theory of Human Slipping

2002 ◽  
Author(s):  
Ralph L. Barnett ◽  
Susanne A. Glowiak ◽  
Peter J. Poczynok
Keyword(s):  
Friction Coefficient ◽  
Duty Cycle ◽  
Stochastic Theory ◽  
The Other ◽  
Extreme Value Statistics ◽  
Conventional Theory ◽  
Low Friction ◽  
Friction Coefficients ◽  
Duty Cycles ◽  
New Concepts

The conventional approach to human slipping is essentially deterministic; it states that no slipping will occur when the average friction coefficient is greater than some critical friction criterion. Under this condition, pedestrians will not slip when they encounter the average friction coefficient. On the other hand, to successfully negotiate a walk of n-steps they must not slip when they encounter the smallest of the n friction coefficients. Consequently, a new slip theory has been formulated as a problem in extreme value statistics. An elegant relationship is obtained among the probability of slipping, the critical friction criterion, the number of steps taken by the walker, and the central measure, scatter, and asymmetry of the distribution of friction coefficients. The new theory reveals the structure of human slipping in a startling way that introduces completely new concepts: the go/no go nature of classical slip predictions is replaced by a probability of slipping; low friction floor/footwear couples may lead to fewer slips than high friction ones; slipping can occur in any case where conventional theory predicts “no slip”; and the number of slips depends on the distance traveled by a pedestrian. Finally, this paper develops the idea that the slipperiness of a real floor must be evaluated for a duty-cycle. Duty-cycles can be represented as frequency histograms when a floor is homogeneous and isotropic.

scholarly journals Low Friction at the Nanoscale of Hydrogenated Fullerene-Like Carbon Films

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 643
Author(s):  
Zhao Liu ◽  
Yongfu Wang ◽  
Thilo Glatzel ◽  
Antoine Hinaut ◽  
Junyan Zhang ◽  
...  
Keyword(s):  
Wear Debris ◽  
Carbon Films ◽  
Surface Structures ◽  
Nanometer Scale ◽  
Friction Force Microscopy ◽  
Low Friction ◽  
Friction Coefficients ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Friction Regime

Friction force microscopy experiments at the nanometer scale are applied to study low friction of hydrogenated fullerene-like carbon films. The measured friction coefficients indicate that lower hydrogen concentration during preparation is beneficial to enter the low friction regime, especially in combination with only methane as precursor. Furthermore, two regions are found with distinct friction coefficients and surface roughnesses related to different surface structures. One is rich in amorphous carbon and the other is rich in fullerene-like carbon, dispersed on the same surface. Transmission electron microscopy and Raman spectroscopy images verify this observation of the two separated structures, especially with the extracted fullerene-like structures in the wear debris from macro friction experiments. It is speculated that hydrogen may tend to impair the growth of fullerene-like carbon and is therefore detrimental for lubricity.

Unlubricated Sliding Wear of TiN Particle Reinforced Si3N4 Matrix Composites Against AISI-52100 Steel Ball

2007 ◽  
Vol 280-283 ◽  
pp. 1327-1330
Author(s):  
Chien Cheng Liu ◽  
Jow Lay Huang
Keyword(s):  
Friction And Wear ◽  
Wear Behavior ◽  
Matrix Composites ◽  
Wear Properties ◽  
Low Friction ◽  
Friction Coefficients ◽  
A Value ◽  
Aisi 52100 ◽  
Ceramic Components ◽  
Aisi 52100 Steel

The effects of TiN addition to Si3N4 on its mechanical and wear properties were investigated. The size and content of TiN particles were found having effects on the strength and toughness of Si3N4-based composites. The friction and wear behavior of Si3N4 based composites against AISI-52100 steel were investigated in the ball -on- disc mode in a non-lubrication reciprocation motion. It has been found that under the conditions used all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10-8 and 1.389 × 10-6 mm3/N.m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients was reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09×10-8 and 0.32×10-6 mm3/N.m at room temperature.

scholarly journals Multiply Interpenetrating Polymer Networks: Preparation, Mechanical Properties, and Applications

Gels ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 36 ◽  
Author(s):  
Panayiota A. Panteli ◽  
Costas S. Patrickios
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Polymer Network ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Interpenetrating Polymer Network ◽  
Low Friction ◽  
Friction Coefficients ◽  
Polymeric Component ◽  
Work Done

This review summarizes work done on triply, or higher, interpenetrating polymer network materials prepared in order to widen the properties of double polymer network hydrogels (DN), doubly interpenetrating polymer networks with enhanced mechanical properties. The review will show that introduction of a third, or fourth, polymeric component in the DNs would further enhance the mechanical properties of the resulting materials, but may also introduce other useful functionalities, including electrical conductivity, low-friction coefficients, and (bio)degradability.

Structure of Tantalum and Tantalum Oxide Coatings on Steel and Glass Surfaces

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940078 ◽  
Author(s):  
G. B. Melnikova ◽  
A. S. Petrovskaya ◽  
T. A. Kuznetsova ◽  
S. A. Chizhik ◽  
A. Zykova ◽  
...  
Keyword(s):  
Tantalum Oxide ◽  
Medical Applications ◽  
Oxide Coatings ◽  
Low Friction ◽  
Friction Coefficients ◽  
Glass Substrates ◽  
Glass Surfaces

The research of structure, roughness and friction coefficients of tantalum and tantalum oxide coatings on steel and glass substrates by the AFM method is presented. The samples are characterized by low friction coefficients. These materials are proposed for fabrication of stents in medical applications.

scholarly journals Tribological Properties of Mo-Si-B Alloys Doped with La2O3 and Tested at 293–1173 K

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2011 ◽  
Author(s):  
Wenhu Li ◽  
Taotao Ai ◽  
Hongfeng Dong ◽  
Guojun Zhang
Keyword(s):  
High Temperature ◽  
Tribological Properties ◽  
Laser Scanning ◽  
Wear Behavior ◽  
Surface Oxidation ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Friction ◽  
Friction Coefficients ◽  
Wear Rates

According to the stoichiometric ratios of Mo-10Si-7B, Mo-12Si-8.5B, Mo-14Si-9.8B, and Mo-25Si-8.5B, some new Mo-Si-B alloys doped with 0.3 wt % lanthanum (III) oxide (La2O3) were prepared via liquid-liquid (L-L) doping, mechanical alloying (MA), and hot-pressing (HP) sintering technology. The phase-composition and microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The worn surfaces of the plate specimens were studied by confocal laser scanning microscopy (CLSM). Then, the tribological properties of Mo-Si-B alloy doped with sliding plate specimens of 0.3 wt % La2O3 were investigated against the Si3N4 ball specimens. The friction coefficients of Mo-Si-B alloys decreased and the wear rates of the alloys increased with test load. The high-temperature friction and wear behavior of Mo-Si-B alloy are related to the surface-oxidation and contact-deformation of the alloy at a high temperature. The low friction coefficients and the reduced wear rates are thought to be due to the formation of low friction MoO3 films. MoO3 changed the contact state of the friction pairs and behaved as lubricating films.

Friction and Wear Properties of Zr and TiC-Based Cermet Specimens in a Hydrogen Gas Atmosphere

2010 ◽  
Vol 638-642 ◽  
pp. 3412-3417 ◽  
Author(s):  
Takashi Murakami ◽  
Katsuo Kaneda ◽  
Hiroki Mano ◽  
Masayuki Hata ◽  
Shinya Sasaki ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Friction And Wear ◽  
Hydrogen Gas ◽  
Layered Crystal ◽  
Wear Properties ◽  
Low Friction ◽  
Friction Coefficients ◽  
Layered Crystal Structure ◽  
Gas Atmosphere ◽  
Friction And Wear Properties

In this study, Zr, Ti and TiC-based cermet specimens were prepared, and their friction and wear properties in various gas atmospheres were examined. The Zr specimens exhibited the lowest friction coefficients and the smallest volume change in the H2 gas atmosphere. This reason would have been due to the formation of the -type Zr hydride, which has a layered crystal structure. The Ti specimens exhibited similar friction and wear properties, although the TiC-based cermet specimens containing small amount of Mo, Ni and W exhibited the lowest friction coefficients in air, not in the H2 gas atmosphere. The low friction coefficients of the cermet specimens in air is likely to have been due to the formation of the low friction Mo oxides and W oxides.

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