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Superlubricity behaviors of Nitinol 60 alloy under oil lubrication 被引量:6
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作者 曾群锋 董光能 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期354-359,共6页
The tribological tests were performed using Nitinol 60 alloy pin sliding over GCr15 steel disc in the tribometer system. Four kinds of oils were experimentally investigated as lubrication oils for lubricating Nitinol ... The tribological tests were performed using Nitinol 60 alloy pin sliding over GCr15 steel disc in the tribometer system. Four kinds of oils were experimentally investigated as lubrication oils for lubricating Nitinol 60 alloy in the boundary lubrication regime. The experimental results were compared with a reference dry friction. It was found that Nitinol 60 alloy can be lubricated significantly and has shown remarkable lubrication performance. A superlubricity behavior of Nitinol 60 alloy was observed under castor oil lubrication. An ultra-low coefficient of friction of Nitinol 60 alloy about 0.008 between Nitinol 60 alloy and GCr15 steel was obtained under castor oil lubrication condition after a running-in period. Accordingly, the present study is focused on the lubrication behaviors of castor oil as potential lubrication oil for Nitinol 60 alloy. In the presence of castor oil, coefficient of friction is kept at 0.008 at steady state, corresponding to so-called superlubricity regime (when sliding is then approaching pure rolling). The mechanism of superlubricity is attributed to the triboformed OH-terminated surfaces from friction-induced dissociation of castor oil and the boundary lubrication films formed on the contact surface due to high polarity and long chain of castor oil allowing strong interactions with the lubricated surfaces. 展开更多
关键词 Nitinol 60 alloy oil lubrication SUPERlubricity lubrication films
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Effects of Fatty Acids on Low-Sulfur Diesel Lubricity:Experimental Investigation, DFT Calculation and MD Simulation 被引量:6
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作者 Luo Hui Fan Weiyu +2 位作者 Li Yang Zhao Pinhui Nan Guozhi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第2期74-81,共8页
The continuous reduction in sulfur content of fuels would lead to diesel fuel with poor lubricity which could re- sult in engine pump failure. In the present work, fatty acids were adopted as lubricity additives to lo... The continuous reduction in sulfur content of fuels would lead to diesel fuel with poor lubricity which could re- sult in engine pump failure. In the present work, fatty acids were adopted as lubricity additives to low-sulfur diesel fuel. It was attempted to correlate the molecular structures of fatty acids, such as carbon chain length, degree of saturation and hy- droxylation, to their lubricity enhancement, which was evaluated by the High-Frequency Reciprocating Rig (HFRR) meth- od. The efficiency order was supported by the density functional theory (DFT) calculations and the molecular dynamics (MD) simulations. The lubricity enhancing properties of fatty acids are mainly determined by the cohesive energy of adsorbed films furmed on iron surface. The greater the cohesive energy, the more efficiently the fatty acid would enhance the lubricity of low-sulfur diesel fuel. 展开更多
关键词 lubricity fatty acid DFT MD simulation ADSORPTION
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Experimental and Molecular Dynamics Simulations for Investigating the Effect of FattyAcid and Its Derivatives on Low Sulfur Diesel Lubricity 被引量:4
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作者 Luo Hui Fan Weiyu +2 位作者 Li Yang Zhao Pinhui Nan Guozhi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第3期79-85,共7页
In this work,fatty acid and its derivatives were adopted as lubricity additives for low sulfur diesel.Tribological evaluation obtained from the High-Frequency Reciprocating Rig(HFRR)apparatus showed that the lubricati... In this work,fatty acid and its derivatives were adopted as lubricity additives for low sulfur diesel.Tribological evaluation obtained from the High-Frequency Reciprocating Rig(HFRR)apparatus showed that the lubricating performance of the additives increased in the following order:stearic acid>glycol monopalmitate>stearyl alcohol>ethyl palmitate>cetyl ethyl ether.The adsorption behavior of the additives on Fe(110)surface and Fe2O3(001)surface was investigated by molecular dynamics(MD)simulations to verify their lubricity performance.The results suggested that adsorption energies of the additives on Fe(110)surface are determined by the van der Waals forces,while adsorptions on Fe2O3(001)surface are significantly attributed to the electrostatic attractive forces.Higher values of adsorption energy of the additives on Fe2O3(001)surface indicate that the additive has more efficient lubricity enhancing properties. 展开更多
关键词 MD simulation ADSORPTION lubricity additive fatty acid low-sulfur diesel
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Superlubricity of a Mixed Aqueous Solution 被引量:4
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作者 MA Zhi-Zuo ZHANG Chen-Hui +2 位作者 LUO Jian-Bin LU Xin-Chun WEN Shi-Zhu 《Chinese Physics Letters》 SCIE CAS CSCD 2011年第5期191-194,共4页
A super-low friction coefficient of 0.0028 is measured under a pressure of 300MPa when the friction pair(the silicon nitride ball sliding on the silicate glass)is lubricated by the mixed aqueous solution of glycerol a... A super-low friction coefficient of 0.0028 is measured under a pressure of 300MPa when the friction pair(the silicon nitride ball sliding on the silicate glass)is lubricated by the mixed aqueous solution of glycerol and boric acid.The morphorlogies of the hydroxylated glass plate are observed by an atomic force microscope(AFM)in deionized water,glycerol,boric acid and their mixed aqueous solution.Bonding peaks of the retained liquids adhered on the surface of the sliding track are detected by an infrared spectrum apparatus and a Raman spectrum apparatus.The mechanism of the superlubricity of the glycerol and boric acid mixed aqueous solution is discussed.It is deduced that the formation of the lubricant film has enough strength to support higher loads,the hydration effect offering the super lower shear resistance. 展开更多
关键词 SUPERlubricity water based lubricant ultra-low friction
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Experimental and Molecular Simulations for Evaluating the Effect of Lubricity Improvers on the Property of Jet Fuel
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作者 Li Jin Hu Zexiang +2 位作者 Chen Guoxu Tao Zhiping Zhao Jie 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2016年第2期80-84,共5页
Since the 1990 s, the kerosene fuel(code: JP-8) had been applied in the ground equipment provided with direct injection compression ignition engines in the U.S. Army, resulting in increased occurrence of injection pum... Since the 1990 s, the kerosene fuel(code: JP-8) had been applied in the ground equipment provided with direct injection compression ignition engines in the U.S. Army, resulting in increased occurrence of injection pump failures. Anti-wear additives must be used in the single fuel due to its poor lubricity. In the present work, lubricity improvers were selected on the basis of molecular simulation theoretically and these agents were evaluated to improve the lubricity of jet fuel using the high frequency reciprocating rig(HFRR) apparatus and the ball-on-cylinder lubricity evaluator(BOCLE). It was revealed that dimer acid with higher value of adsorption energy on the Fe(110) plane surface had more efficient lubricity promoting properties than that of naphthenic acid. The experimental results suggested that the dimer acid had a better tribological behavior compared with that of naphthenic acid used as lubricity improver of jet fuel. And addition of anti-wear additives at a dosage of 15 μg/g was able to promote the lubricity of jet fuel to a required level on BOCLE, while a higher concentration over 80 μg/g was needed to improve the lubricity to a demanded value of diesel on HFRR. 展开更多
关键词 JET fuel DIESEL lubricity DIMER ACID naphthenic ACID molecular simulation
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Lubricity of Rare Earth Compounds in Oil
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作者 陈波水 叶毅 董浚修 《Journal of Rare Earths》 SCIE EI CAS CSCD 1998年第3期61-63,共3页
The lubricities of fifteen rare earth compounds of lanthanum, praseodymium, samarium, europium and gadolinium are evaluated on a four ball tester and compared with that of ZDDP(Zinc Dialkyldithiophosphate). Results s... The lubricities of fifteen rare earth compounds of lanthanum, praseodymium, samarium, europium and gadolinium are evaluated on a four ball tester and compared with that of ZDDP(Zinc Dialkyldithiophosphate). Results show that some of rare earth compounds provide much better lubricities than ZDDP, and the hexagonal type of rare earth metal compounds exhibit better lubricites than the body centered cubic type of metal compounds. 展开更多
关键词 Rare earths COMPOUND lubricity
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Scalable preparation of functionalized graphite nanoplatelets via magnetic grinding as lubricity-enhanced additive
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作者 季海滨 何志伟 +1 位作者 宋沙沙 赵增典 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第11期2800-2808,共9页
Graphite nanoplatelets were prepared by a novel magnetic-grinding method using self-made equipments. Under a variant magnetic field, magnetic needles collided at a high rotating speed and exfoliated pristine graphite ... Graphite nanoplatelets were prepared by a novel magnetic-grinding method using self-made equipments. Under a variant magnetic field, magnetic needles collided at a high rotating speed and exfoliated pristine graphite into graphite nanoplatelets with high efficiency. The obtained graphite nanoplatelets are highly crystalline, and the thickness is less than 10 nm. Moreover, the surface area could reached 738.1 m^2/g with a grinding time of 4 h. Silanized graphite nanoplatelets can disperse well in SG 15W-40 engine oil and serve as lubricant additive. Tribological results indicate that the friction coefficient and wear-scar of the friction pairs are lower than 76% and 41%, respectively, by adding 1.5‰(mass fraction) of silanized graphite nanoplatelets. Notably, the functionalized graphite nanoplatelets can realize large-scale production and commercial application. 展开更多
关键词 magnetic grinding graphite nanoplatelets SILANIZATION lubricant additives
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Liquid superlubricity of lubricants containing hydroxyl groups and their aqueous solution under rolling/sliding conditions 被引量:1
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作者 Tomáš POLÁČEK Petr ŠPERKA Ivan KŘUPKA 《Friction》 SCIE EI CAS CSCD 2024年第1期164-173,共10页
Macroscale rolling/sliding conditions are in the superlubricity,a little-studied topic so far.The purpose of this paper is to examine the formation of elastohydrodynamic lubrication(EHL)films by water-based lubricants... Macroscale rolling/sliding conditions are in the superlubricity,a little-studied topic so far.The purpose of this paper is to examine the formation of elastohydrodynamic lubrication(EHL)films by water-based lubricants(glycerol and polyethylene glycol(PEG)),providing superlubricous friction.Experiments were carried out on an optical ball-on-disc tribometer under rolling/sliding conditions.The film thickness was measured by the thin film colorimetric interferometry,and the viscosity of liquids was measured by rotational and high-pressure falling body viscometers.The results show that tribochemical reactions are not the mandatory reason for friction to reach the superlubricity level when using the water-based lubricants.The studied liquids themselves are almost Newtonian.With the addition of water,the signs of shear thinning behavior disappear even more.Suitable conditions for this type of lubricant can be predicted using the known Hamrock–Dowson equations.An anomaly in the thickness of the lubricants was observed as an abrupt change at certain conditions.The more PEG there is in the lubricant,the higher the thickness at the beginning of the jump. 展开更多
关键词 macroscale superlubricity super low traction water-based lubricants elastohydrodynamic lubrication(EHL) film thickness
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Combination of diketone and PAO to achieve macroscale oil-based superlubricity at relative high contact pressures 被引量:1
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作者 Shaonan DU Chenhui ZHANG Zhi LUO 《Friction》 SCIE EI CAS CSCD 2024年第5期869-883,共15页
1-(4-ethylphenyl)-nonane-1,3-dione(0206)is an oil-soluble liquid molecule with rod-like structure.In this study,the chelate(0206-Fe)with octahedral structure was prepared by the reaction of ferric chloride and 1,3-dik... 1-(4-ethylphenyl)-nonane-1,3-dione(0206)is an oil-soluble liquid molecule with rod-like structure.In this study,the chelate(0206-Fe)with octahedral structure was prepared by the reaction of ferric chloride and 1,3-diketone.The experimental results show that when using 0206 and a mixed solution containing 60%0206-Fe and 40%0206(0206-Fe(60%))as lubricants of the steel friction pairs,superlubricity can be achieved(0.007,0.006).But their wear scar diameters(WSD)were very large(532µm,370µm),which resulted in the pressure of only 44.3 and 61.8 MPa in the contact areas of the friction pairs.When 0206-Fe(60%)was mixed with PAO6,it was found that the friction coefficient(COF)decreased with increase of 0206-Fe(60%)in the solution.When the ratio of 0206-Fe(60%)to PAO6 was 8:2(PAO6(20%)),it exhibited better comprehensive tribological properties(232.3 MPa).Subsequent studies have shown that reducing the viscosity of the base oil in the mixed solution helped to reduce COF and increased WSD.Considering the COF,contact pressure,and running-in time,it was found that the mixed lubricant(Oil3(20%))prepared by the base oil with a viscosity of 19.7 mPa·s(Oil3)and 0206-Fe(60%)exhibited the best tribological properties(0.007,161.4 MPa,3,100 s). 展开更多
关键词 DIKETONE oil-based lubricants CHELATE SUPERlubricity
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Research progress on rolling superlubricity in solid lubricants
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作者 LI PanPan LI HongXuan +8 位作者 ZHU DongXiang ZHU YongQi KANG FuYan WANG Wan ZHANG YaXin LIU XiaoHong JI Li ZHOU HuiDi CHEN JianMin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第7期1980-1990,共11页
Superlubricity is an ideal lubrication state where friction nearly vanishes between contact interfaces. It has become one of the most important research topics and approaches owing to its significance in reducing ener... Superlubricity is an ideal lubrication state where friction nearly vanishes between contact interfaces. It has become one of the most important research topics and approaches owing to its significance in reducing energy consumption and preventing device failures. As an efficient and universal lubricating principle capable of achieving superlubricity, rolling lubrication has attracted widespread attention in recent years. In this review, the theoretical concept of rolling lubrication and the experimental research progress of spherical/scroll structures are summarized. The review focuses on the possibility of achieving rolling lubrication using spherical/scroll structures(such as spherical fullerenes, carbon nanotubes, and formed and constructed spherical/scroll structures). The challenges in achieving rolling lubrication are summarized, and the possibility of molecular rolling lubrication,as well as its potential applications in superlubrication, are discussed. 展开更多
关键词 spherical/scroll structure rolling lubrication SUPERlubricity FULLERENE
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Superlubricity on the nanometer scale 被引量:6
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作者 Ernst MEYER Enrico GNECCO 《Friction》 SCIE EI CAS 2014年第2期106-113,共8页
The transition from atomic stick-slip to continuous sliding has been observed in a number of ways.If extended contacts are moved in different directions,so-called structural lubricity is observed when the two surface ... The transition from atomic stick-slip to continuous sliding has been observed in a number of ways.If extended contacts are moved in different directions,so-called structural lubricity is observed when the two surface lattices are non-matching.Alternatively,a“superlubric”state of motion can be achieved if the normal force is reduced below a certain threshold,the temperature is increased,or the contact is actuated mechanically.These processes have been partially demonstrated using atomic force microscopy,and they can be theoretically understood by proper modifications of the Prandtl−Tomlinson model. 展开更多
关键词 structural lubricity dynamic superlubricity atomic force microscopy friction force microscopy themolubricity Prandtl−Tomlinson model
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A novel polyionic liquid with lubricity and viscosity-increasing dual functionalities as the additive in aqueous lubrication system
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作者 Bo YU Kun ZOU +8 位作者 Rui WANG Qiang CHEN Rui DONG Xiao LIU Jiaying ZHANG Wenquan LV Qiangliang YU Meirong CAI Feng ZHOU 《Friction》 SCIE EI CAS CSCD 2024年第4期698-710,共13页
The polyionic liquid poly-PEGMA-r-METAC(PPM)with quaternary ammonium has been synthesized and evaluated as additive in aqueous lubricating fluids.The rheological behavior of aqueous lubricating fluids with PPM has bee... The polyionic liquid poly-PEGMA-r-METAC(PPM)with quaternary ammonium has been synthesized and evaluated as additive in aqueous lubricating fluids.The rheological behavior of aqueous lubricating fluids with PPM has been characterized to confirm PPM’s function as a viscosity modifier.The tribological behavior of aqueous lubricating fluids with PPM has been investigated on SRV-V and MTM testing machines.It was found that PPM has excellent viscosity-increasing,lubricating,and anti-wear properties as an additive for aqueous,which can be attributed to the ability of PPM to form the protective film and boundary tribofilm generated from complex tribochemical reaction on rubbing surface.The obtained PPM with dual functions of anti-corrosion additives and viscosity index improver can play an important role in diverse lubrication regimes. 展开更多
关键词 polyionic liquid lubricant additives viscosity modifier lubrication regime
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Experimental study on boundary lubricity of superficial area of articular cartilage and synovial fluid
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作者 Wenxiao LI Takehiro MORITA Yoshinori SAWAE 《Friction》 SCIE EI CAS CSCD 2024年第5期981-996,共16页
The boundary lubrication mechanism at the articulating surface of natural synovial joints has been the subject of much discussion in tribology.In this study,to elucidate the lubricating function of the superficial are... The boundary lubrication mechanism at the articulating surface of natural synovial joints has been the subject of much discussion in tribology.In this study,to elucidate the lubricating function of the superficial area of articular cartilage and synovial fluid(SF),cartilage specimens were processed with four different treatments:gentle and severe washing with detergent,incubation in NaCl solution,and trypsin digestion to selectively remove certain constituents from the cartilage surface.Subsequently,the frictional characteristics were examined in phosphate-buffered saline(PBS)and SF against glass.Angularly reciprocating sliding tests with a spherical glass probe and square articular cartilage specimens were performed at low contact loads in the mN range to extract the frictional behavior in the superficial area of the cartilage specimens.Meanwhile,the cartilage surface was observed to confirm the effects of treatments on the morphology of the cartilage surface using a fluorescence microscope and water-immersion methods.The coefficient of friction(COF)of the prepared cartilage specimens was varied from 0.05 to over 0.3 in PBS.However,a certain group of cartilage specimens exhibited a low COF of less than 0.1 with limited variation.For the low COF group of specimens,all four treatments increased the COF in PBS to different extents,and fluorescence microscopy revealed that the integrity of the cartilage surface was deteriorated by treatments.This means that the intact cartilage surface had lubricating constituents to maintain low friction,and the removal of such constituents resulted in the loss of the intrinsic boundary lubricity of the cartilage surface.The variation in the COF of the cartilage specimens was suppressed in SF because it had a clear boundary lubrication effect on the cartilage surface.The lubricating effect of SF could be confirmed even after degenerative treatment. 展开更多
关键词 articular cartilage synovial fluid the uppermost superficial layer boundary lubrication
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Nanotribological studies using nanoparticle manipulation: Principles and application to structural lubricity 被引量:3
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作者 Dirk DIETZEL Udo DSCHWARZ AndréSCHIRMEISEN 《Friction》 SCIE EI CAS 2014年第2期114-139,共26页
The term“structural lubricity”denotes a fundamental concept where the friction between two atomically flat surfaces is reduced due to lattice mismatch at the interface.Under favorable circumstances,its effect may ca... The term“structural lubricity”denotes a fundamental concept where the friction between two atomically flat surfaces is reduced due to lattice mismatch at the interface.Under favorable circumstances,its effect may cause a contact to experience ultra-low friction,which is why it is also referred to as“superlubricity”.While the basic principle is intriguingly simple,the experimental analysis of structural lubricity has been challenging.One of the main reasons for this predicament is that the tool most frequently used in nanotribology,the friction force microscope,is not well suited to analyse the friction of extended nanocontacts.To overcome this deficiency,substantial efforts have been directed in recent years towards establishing nanoparticle manipulation techniques,where the friction of nanoparticles sliding on a substrate is measured,as an alternative approach to nanotribological research.By choosing appropriate nanoparticles and substrates,interfaces exhibiting the characteristics needed for the occurrence of structural lubricity can be created.As a consequence,nanoparticle manipulation experiments such as in this review represent a unique opportunity to study the physical conditions and processes necessary to establish structural lubricity,thereby opening a path to exploit this effect in technological applications. 展开更多
关键词 NANOTRIBOLOGY nanoparticle manipulation friction force microscopy structural lubricity SUPERlubricity HOPG
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Achieving superlubricity in DLC films by controlling bulk, surface, and tribochemistry 被引量:25
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作者 Ali ERDEMIR Osman ERYILMAZ 《Friction》 SCIE EI CAS 2014年第2期140-155,共16页
Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction[1].From a practical application point of view,this will be the most ideal tribo... Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction[1].From a practical application point of view,this will be the most ideal tribological situation for many moving mechanical systems mainly because friction consumes large amounts of energy and causes greenhouse gas emissions[2].Superlubric sliding can also improve performance and durability of these systems.In this paper,we attempt to provide an overview of how controlled or targeted bulk,surface,or tribochemistry can lead to superlubricity in diamond-like carbon(DLC)films.Specifically,we show that how providing hydrogen into bulk and near surface regions as well as to sliding contact interfaces of DLC films can lead to super-low friction and wear.Incorporation of hydrogen into bulk DLC or near surface regions can be done during deposition or through hydrogen plasma treatment after the deposition.Hydrogen can also be fed into the sliding contact interfaces of DLCs during tribological testing to reduce friction.Due to favorable tribochemical interactions,these interfaces become very rich in hydrogen and thus provide super-low friction after a brief run-in period.Regardless of the method used,when sliding surfaces of DLC films are enriched in hydrogen,they then provide some of the lowest friction coefficients(i.e.,down to 0.001).Time-of-flight secondary ion mass spectrometer(TOF-SIMS)is used to gather evidence on the extent and nature of tribochemical interactions with hydrogen.Based on the tribological and surface analytical findings,we provide a mechanistic model for the critical role of hydrogen on superlubricity of DLC films. 展开更多
关键词 SUPERlubricity diamond-like carbon TOF-SIMS test environment lubrication mechanisms
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Investigations of the superlubricity of sapphire against ruby under phosphoric acid lubrication 被引量:13
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作者 Jinjin LI Chenhui ZHANG +1 位作者 Mingming DENG Jianbin LUO 《Friction》 SCIE EI CAS 2014年第2期164-172,共9页
In this study,we address the superlubricity behavior of sapphire against ruby(or sapphire against itself)under phosphoric acid solution lubrication.An ultra-low friction coefficient of 0.004 was obtained under a very ... In this study,we address the superlubricity behavior of sapphire against ruby(or sapphire against itself)under phosphoric acid solution lubrication.An ultra-low friction coefficient of 0.004 was obtained under a very high contact pressure,with a virgin contact pressure up to 2.57 GPa.Related experiments have indicated that the load,sliding speed,and humidity of the test environment can affect superlubricity to some degree,so we tested variations in these conditions.When superlubricity appears in this study a thin film is present,consisting of a hydrogen bond network of phosphoric acid and water molecules adsorbed on the two friction surfaces,which accounts for the ultra-low friction.Most significantly,the wear rate of the sapphire and ruby in the friction process is very slow and the superlubricity state is very stable,providing favorable conditions for future technological applications. 展开更多
关键词 FRICTION SUPERlubricity SAPPHIRE aqueous lubrication
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Molecular behaviors in thin film lubrication——Part three: Superlubricity attained by polar and nonpolar molecules 被引量:17
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作者 Xiangyu GE Tobias HALMANS +1 位作者 Jinjin LI Jianbin LUO 《Friction》 SCIE CSCD 2019年第6期625-636,共12页
In thin-film lubrication(TFL), generally, the viscosity of the lubricant and its coefficient of friction(Co F) increase. Finding a method to reduce the Co F in TFL is a significant challenge for tribologists. In the p... In thin-film lubrication(TFL), generally, the viscosity of the lubricant and its coefficient of friction(Co F) increase. Finding a method to reduce the Co F in TFL is a significant challenge for tribologists. In the present work, we report a robust superlubricity attained by using polyalkylene glycols(PAGs, polar molecules) and poly-α-olefins(PAOs, nonpolar molecules) as lubricants on steel/steel friction pairs that have been pre-treated by wearing-in with polyethylene glycol aqueous solution(PEG(aq)). A steady superlubricity state with a Co F of 0.0045 for PAG100 and 0.006 for PAO6 could be maintained for at least 1 h. Various affecting factors, including the sliding velocity, normal load, and viscosity of the lubricants, were investigated. Element analysis proved that composite tribochemical layers were deposited on the worn region after the treatment with PEG(aq). These layers were formed by the tribochemical reactions between PEG and steel and composed of various substances including oxides, iron oxides, Fe OOH, and Fe(OH)3, which contributed to the superlubricity. In addition to the tribochemical layers, ordered layers and a fluid layer were formed by the PAGs and PAOs during the superlubricity periods. All the three types of layers contributed to the superlubricity, indicating that it was attained in the TFL regime. Accordingly, a mechanism was proposed for the superlubricity of the PAGs and PAOs in the TFL regime in this work. This study will increase the scientific understanding of the superlubricity in the TFL regime and reveal, in the future, the potential for designing superlubricity systems on steel surfaces for industrial applications. 展开更多
关键词 thin film lubrication SUPERlubricity PEG PAG PAO
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Effect of dicarboxylic acid esters on the lubricity of aviation kerosene for use in CI engines 被引量:10
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作者 G.ANASTOPOULOS S.KALLIGEROS +1 位作者 P.SCHINAS F.ZANNIKOS 《Friction》 SCIE EI CAS 2013年第3期271-278,共8页
To reduce their fuel related logistic burden,North Atlantic Treaty Organization(NATO)Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment.To this end,F-34(the commercial equivalen... To reduce their fuel related logistic burden,North Atlantic Treaty Organization(NATO)Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment.To this end,F-34(the commercial equivalent is Jet A-1)is replacing distillate diesel fuel in many applications.However,tests conducted with this kerosene type on high frequency reciprocating rig showed that this type of fuel causes unacceptable wear.This excessive wear is caused by the poor lubricity of aviation fuel.In order to make this type of fuel compatible with direct injection compression engines,seven di-carboxylic acid esters have tested to improve the lubricity of kerosene.Tribological results showed that all esters tested in this series of experiments seem to be suitable for increasing the kerosene lubricity to a satisfactory level. 展开更多
关键词 lubricity aviation kerosene F-34 Jet A-1 compression ignition(CI)engines dicarboxylic acid esters
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Hydrodynamic effect on the superlubricity of phosphoric acid between ceramic and sapphire 被引量:11
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作者 Mingming DENG Chenhui ZHANG +2 位作者 Jinjin LI Liran MA Jianbin LUO 《Friction》 SCIE EI CAS 2014年第2期173-181,共9页
In this work,a super-low friction coefficient of 0.003 was found between a silicon nitride ball and a sapphire plate lubricated by phosphoric acid solution.The wear mainly occurred in the running-in period and disappe... In this work,a super-low friction coefficient of 0.003 was found between a silicon nitride ball and a sapphire plate lubricated by phosphoric acid solution.The wear mainly occurred in the running-in period and disappeared after superlubricity was achieved.The friction coefficient was effectively reduced from 0.3 to 0.003 at a constant speed of 0.076 m/s,accompanied by a 12-nm-thickness film.The lubrication regime was indicated to change from boundary lubrication in the running-in period to elastohydrodynamic lubrication in the superlubricity period,which is also supported by the results of the friction coefficient versus sliding speed.In addition,the experimental results showed good agreement with theoretical calculations based on the elastohydrodynamic lubrication theory,suggesting a significant hydrodynamic effect of phosphoric acid on superlubricity. 展开更多
关键词 liquid superlubricity phosphoric acid hydrodynamic lubrication film thickness
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Superlubricity achieved with two-dimensional nano-additives to liquid lubricants 被引量:12
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作者 Hongdong WANG Yuhong LIU 《Friction》 SCIE CSCD 2020年第6期1007-1024,共18页
The topic of superlubricity is attracting considerable interest around the world while humanity is facing an energy crisis.Since various liquid superlubricity systems can be commonly achieved on the macroscale in ambi... The topic of superlubricity is attracting considerable interest around the world while humanity is facing an energy crisis.Since various liquid superlubricity systems can be commonly achieved on the macroscale in ambient conditions,it is considered an effective solution to reduce unnecessary energy and material losses.However,certain practical problems such as low load-bearing pressure,dependence on hydrogen ions,and relatively long running-in processes still limit its widespread application.Two-dimensional(2D)nano-additives with ultrathin longitudinal dimensions can lower the shear resistance between sliding solid surfaces,and thus further optimize the applied conditions.In this review,the latest studies on 2D nano-additives with a combination of various water-based lubricants in the state of superlubricity are reported,typically including black phosphorus(BP),graphene oxide(GO),and layered double hydroxide.During the sliding process,composite lubricants effectively improved the load capacity(up to 600 MPa),reduced wear,and accelerated the running-in period(within 1,000 s)of the liquid superlubricity system.Both macromechanical experiments and microscopic tests are conducted to precisely analyze various interactions at the interfaces of the nano-additives and solid surfaces.These interactions can be described as tribochemical reactions,physical protection,and adsorption enhancement,and improved wear resistance.This review provides better guidance for applying 2D nanomaterials in liquid superlubricity systems. 展开更多
关键词 SUPERlubricity two-dimensional(2D)nanomaterial lubricant additive WATER-BASED tribological property
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