检索结果-南通市图书馆

Comparative analysis of frictional behavior and mechanism of molybdenum ditelluride with different structures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第1期12卷 110-119页

作者： Lina ZHANG Xinfeng TAN Jianguo JIAO Dan GUO jianbin luo State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)have layered structures with excellent tribological properties.Since the energy difference between hexagonal-molybdenum ditelluride(2H-MoTe_(2))and distorted octahedral-molybdenum ditelluride(1T′-MoTe_(2))is very small among the transition metal dichalcogenides(TMDCs),MoTe_(2) becomes one of the most promising candidates for phase engineering.In our experiment,we found that the friction force and friction coefficient(COF)of 2H-MoTe_(2) were an order of magnitude smaller than those of 1T′-MoTe_(2) by the atomic force microscope(AFM)experiments.The friction difference between 1T′-MoTe_(2) and 2H-MoTe_(2) was further verified in molecular dynamics(MD)simulations.The density functional theory(DFT)calculations suggest that the friction contrast is related to the difference in sliding energy barrier of the potential energy surface(PES)for a tip sliding across the surface.The PES obtained from the DFT calculation indicates that the maximum energy barrier and the minimum energy path(MEP)energy barrier of 2H-MoTe_(2) are both smaller than those of 1T′-MoTe_(2),which means that less energy needs to be dissipated during the sliding process.The difference in energy barrier of the PES could be ascribed to its larger interlayer spacing and weaker Mo–Te interatomic interactions within the layers of 2H-MoTe_(2) than those of 1T′-MoTe_(2).The obvious friction difference between 1T′-MoTe_(2) and 2H-MoTe_(2) not only provides a new non-destructive means to detect the phase transition by the AFM,but also provides a possibility to tune friction by controlling the phase transition,which has the potential to be applied in extreme environments such as space lubrication.

关键词： friction two-dimensional(2D)materials distorted octahedral-molybdenum ditelluride(1T′-MoTe_(2)) hexagonal-molybdenum ditelluride(2H-MoTe_(2)) phase transition

Dynamic friction energy dissipation and enhanced contrast in high frequency bimodal atomic force microscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2022年第5期10卷 748-761页

作者： Xinfeng TAN Dan GUO jianbin luo State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

Dynamic friction occurs not only between two contact objects sliding against each other,but also between two relative sliding surfaces several nanometres apart.Many emerging micro-and nano-mechanical systems that promise new applications in sensors or information technology may suffer or benefit from noncontact friction.Herein we demonstrate the distance-dependent friction energy dissipation between the tip and the heterogeneous polymers by the bimodal atomic force microscopy(AFM)method driving the second order flexural and the first order torsional vibration simultaneously.The pull-in problem caused by the attractive force is avoided,and the friction dissipation can be imaged near the surface.The friction dissipation coefficient concept is proposed and three different contact states are determined from phase and energy dissipation curves.Image contrast is enhanced in the intermediate setpoint region.The work offers an effective method for directly detecting the friction dissipation and high resolution images,which overcomes the disadvantages of existing methods such as contact mode AFM or other contact friction and wear measuring instruments.

关键词： dynamic friction energy dissipation contact states image contrast bimodal atomic force microscopy(AFM)

“Phase Diagram” of Surface Temperature Distribution of Sessile Droplets and the Effects of Evaporative Cooling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2023年第3期20卷 1132-1140页

作者： Chengzhi Yu Liran Ma Xuefeng Xu jianbin luo School of Technology Beijing Forestry UniversityBeijing100083China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084China

The temperature distribution along the surface of evaporating droplets can affect significantly the flow field inside the liquid and consequently the deposition pattern on the substrate. Although a “phase diagram” for the temperature distribution along the droplet surface was revealed by the numerical simulations, its experimental verification has still not been reported. In this paper, the surface temperature of evaporating droplets has been observed by using an infrared (IR) camera. The experimental observations show that three different patterns of temperature distribution along the droplet surface occur in succession with the change of the contact angle during the evaporation process, which is in good agreement with the theoretical predictions by the “phase diagram” of the surface temperature distribution. Furthermore, the effects of evaporative cooling on the “phase diagram” of sessile droplets have been explored. The numerical results indicate that the evaporative cooling effect can alter the size of the phase regions in the “phase diagram”. These results may provide a better understanding of the evaporation process of drying sessile droplets.

关键词： Sessile droplet Surface temperature distribution Phase diagram Evaporative cooling

Extremely low friction on gold surface with surfactant molecules induced by surface potential

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2023年第4期11卷 513-523页

作者： Tianyang GAO Jinjin LI Weiqi WANG jianbin luo State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

An extremely low friction state was observed on the gold surface induced by applying a specific negative potential in cationic surfactant solution.The friction force showed a remarkable reduction from 8.3 to 3.5×10−2 nN(reduced by 99.6%)with increasing the period of negative applied potential,and the final friction coefficient could reduce down to 3×10−4.The extremely low friction state was robust,and it also exhibited an excellent load bearing capacity,which cannot be damaged by a high load.Moreover,the extremely low friction state achieved under negative applied potential could keep stable even after the removal of potential,but failed in a short time,once a specific positive potential was applied.It was demonstrated that there was a stable electro-adsorption of surfactant molecules on the gold surface induced by applying a negative potential,leading to the formation of a bilayer structure on the gold surface.The hydration layers of the bilayer on the gold surface and micelles on the silica probe provided a shear plane with an extremely low shear strength,leading to the extremely low friction state on the gold surface.This study provides a method to achieve extremely low friction state by applied potential.

关键词： extremely low friction applied potential surfactant load bearing capacity

Achieving ultrafast superlubricity with layered double hydroxides

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第5期16卷 6940-6950页

作者： Kunpeng Wang Yuhong Liu Hongdong Wang jianbin luo State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechatronic Engineering Shanghai UniversityShanghai 200444China

Layered double hydroxides(LDHs)have the potential to be superlubricated materials due to their strong adsorption effect and weak internal interaction.However,obtaining stable superlubricity during the ultrafast time(luoroethylene and LDH,leading to macroscale superlubricity.These findings demonstrate that tribochemical treatment of surfaces produces tribofilm that effectively reduces wearing-in time and promotes ultralow friction.

关键词： superlubricity ultrafast wearing-in time bearing steel LDH nanosheets sliding barrier

Guest editorial:Special Issue on Biomedical Tribology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2022年第1期10卷 2-3页

作者： Guoxin XIE jianbin luo State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

Biomedical tribology has developed rapidly with the joint efforts of medical and tribological researchers,and it concerns various kinds of friction that existed inside and out side the body,such as the friction of joints,the friction between skin and clothing,and the friction in the lumen(blood vessels,trachea,digestive tube,and excretory tube),which causes maiiy physiological changes and diseases in the human body.Besides,many medical devices have been used to treat or alleviate various diseases.Biomedical tribology plays a vital role in solving the widespread tribological issues in the medical devices field,aiming to improve the performance of medical devices and prolong the service life.

关键词： friction tribological service

Low friction of superslippery and superlubricity:A review

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第7期11卷 1121-1137页

作者： Zijian ZHENG Zhiguang GUO Weimin LIU jianbin luo Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials Hubei UniversityWuhan 430062China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

The issues regarding energy dissipation and component damage caused by the interface friction between a friction pair attract enormous attention to friction reduction.The key-enabling technique to realize friction reduction is the use of lubricants.The lubricants smooth the contact interfaces,achieving an ultralow friction contact,which is called superslippery or superlubricity.At present,superslippery and superlubricity are two isolated research topics.There is a lack of unified definition on superslippery and superlubricity from the viewpoint of tribology.Herein,this review aims at exploring the differences and relations between superslippery and superlubricity from their origin and application scenarios.Meanwhile,the challenges for developing superslippery surface and superlubricity surface are discussed.In addition,perspectives on the interactive development of these two surfaces are presented.We hope that our discussion can provide guidance for designing superslippery or superlubricity surfaces by using varies drag-reduction technologies.

关键词： low friction superslippery superlubricity tribology lubricants

Superlubricity induced by partially oxidized black phosphorus on engineering steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2023年第9期11卷 1592-1605页

作者： Kai GAO Jianguo JIAO Zheng WANG Guoxin XIE jianbin luo State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China School of Engineering and Technology China University of Geosciens(Beijing)Beijing 100083China

Macroscale superlubricity has attracted increasing attention owing to its high significance in engineering and economics.We report the superlubricity of engineering materials by the addition of partially oxidized black phosphorus(oBP)in an oleic acid(OA)oil environment.The phosphorus oxides produced by active oxidation exhibit lower friction and quick deposition performance compared to BP particles.The H-bond(–COOH…O–P,or–COOH…O=P)formed between P–O bond(or P=O)and OA molecule could benefit the lubricating state and decrease the possibility of direct contact between rough peaks.The analysis of the worn surface indicates that a three-layer tribofilm consisting of amorphous carbon,BP crystal,and phosphorus oxide forms during the friction,which replaces the shear interface from the steel/steel to carbon–oBP/carbon–oBP layer and enables macroscale superlubricity.

关键词： black phosphorus(BP) macroscale superlubricity oleic acid(OA) active oxidation

Interlayer friction behavior of molybdenum ditelluride with different structures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第8期16卷 11375-11382页

作者： Lina Zhang Xinfeng Tan Jianguo Jiao Dan Guo jianbin luo State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

The interlayer friction behavior of two-dimensional transition metal dichalcogenides(TMDCs)as crucial solid lubricants has attracted extensive attention in the field of tribology.In this study,the interlayer friction is measured by laterally pushing the MoTe_(2)powder on the MoTe_(2)substrate with the atomic force microscope(AFM)tip,and density functional theory(DFT)simulations are used to rationalize the experimental results.The experimental results indicate that the friction coefficient of the 1T'-MoTe_(2)/1T'-MoTe_(2)interface is 2.025×10^(−4),which is lower than that of the 2H-MoTe_(2)/2H-MoTe_(2)interface(3.086×10^(−4)),while the friction coefficient of the 1T'-MoTe_(2)/2H-MoTe_(2)interface is the lowest at 6.875×10^(−5).The lower interfacial friction of 1T'-MoTe_(2)/1T'-MoTe_(2)compared to 2H-MoTe_(2)/2H-MoTe_(2)interface can be explained by considering the relative magnitudes of the ideal average shear strengths and maximum shear strengths based on the interlayer potential energy.Additionally,the smallest interlayer friction observed at the 1T'-MoTe_(2)/2H-MoTe_(2)heterojunction is attributed to the weak interlayer electrostatic interaction and reduction in potential energy corrugation caused by the incommensurate contact.This work suggests that MoTe_(2)has comparable interlayer friction properties to MoS_(2)and is expected to reduce interlayer friction in the future by inducing the 2H-1T'phase transition.

关键词： two-dimensinal materials MoTe_(2) interlayer friction interlayer shear strength