TRIBOLOGY INTERNATIONAL
·
2024
·
IF 6.1
Tian Zhang,Liangliang Xiong,Zhongpan Zhang,Xiaoqiang Fan
To achieve the desired performance of ultra-low friction and wear, we devised an ingenious solid-grease composite lubrication coating (TXL) that combined parallel-arranged Ti 3 C 2 T x resin coatings (TX) and lithium complex grease (LCG). The TX coating facilitated in-situ supply of Ti 3 C 2 T x and effectively inhibited crack propagation, while the LCG ensured a stable oil film bearing capacity. The Stribeck theory demonstrates that TXL consistently remained in boundary lubrication. At 253.93 MPa for 2 h, pure epoxy (EP) and TX coating failed, while TXL still enhanced anti-friction by 19.57 % and anti-wear by 64.31 % relative to EPL. Combining the dual advantages of Ti 3 C 2 T x that promotes lubrication state change and oil-based films supplied by LCG, TXL demonstrates enormous potential for long-lasting, efficient, and stable lubrication.
研究领域:
材料科学
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机械工程
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产品关联
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 13
·2287
·
IF 5.719
Jiabei Wang,Hong Zhang,Wenjing Hu,Jiusheng Li
Nanomaterials exhibit intriguing tribological performance and have received particular attention in the lubrication field. However, little research has been found that surveyed the application of nanometer Ni in lithium grease. In this study, nanometer Ni with an average size of 100 nm was synthesized by the direct reduction method and dispersed in lithium grease. The feasibility of nanometer Ni as a grease additive in different lubrication scenarios was evaluated by a four-ball friction tester and a TE77 reciprocating friction tester. The lubrication mechanism was analyzed based on the evaluated physical properties of lithium grease and the characterization of the wear surface. The tribology test results showed the tribological properties of lithium grease were enhanced after introducing nanometer Ni. When the dosage was 0.2 wt%, the friction-reducing and anti-wear properties of point-to-point contact increased by 34.8% and 35.2%, respectively, while those of the point-to-flat contact increased by 28.8% and 38.7%, respectively. Our work not only provides theoretical guidance and practical reference for the utilization of nanometer Ni in grease, but also explains several possible lubrication mechanisms of nanomaterials in grease.Keywords:nano-lubrication;lithium grease;additives;nanometer Ni;tribological performance
研究领域:
材料科学
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机械工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Yanping Ren,Xiaoqiang Fan,Kaiyue Lin,Shipeng Chen,Minhao Zhu
The preparation of a low shearing shell on the surface of carbon spheres (CS) is an attractive strategy to improve the lubrication properties of CS. In this study, core–shell structural C@Ag particles were prepared using CS as the hard core and Ag nanoparticles as the soft shell. Then, the additives were mixed with Polyalphaolefin 20 to prepare the C@Ag core–shell-enhanced lithium complex grease (C@Ag-LCG). The physicochemical properties, corrosion resistance, and tribological behaviors of LCGs were investigated. C@Ag-LCG exhibited the best high-temperature resistance and colloidal stability compared with the CS-enhanced lithium complex grease (LCG) and pure LCG. The dropping point and oil separation rate of 0.05 wt% C@Ag-LCG were 255 °C and 2.36 %, respectively. The tribological behavior of greases was tested using a four-ball friction tester, and the main damage mechanism was abrasive wear. The C@Ag additive reduced the average friction coefficient and wear spot diameter by 27.17 % and 26.12 %, respectively. The improved properties were attributed to the synergistic lubrication of hard CS core and soft Ag shell with the rolling, filling, and self-repairing effects, C@Ag deposit films and the self-lubricating oil film, as well as the thickener film and the tribochemical film at the frictional interfaces.
研究领域:
材料科学
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润滑工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
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IF 2.206
Xiaosheng Zhang,Weichao Sun,Huijuan Ma,Hong Xu,Jinxiang Dong
Layered sodium silicates β-Na2Si2O5 and kanemite were synthesized via facile methods under mild conditions. The tribological properties of β-Na2Si2O5 and kanemite utilized as additives in lithium grease were evaluated with a four-ball tester under different experimental conditions. The maximum nonseizure load value of 5.0 wt % β-Na2Si2O5 grease jumped from 353 N (the base grease) to 1568 N. However, 5.0 wt % MoS2 grease could only reach 617 N under the same conditions. The SEM and EDS results confirm that a protective film mainly composed of sodium silicates was formed on the worn surface during the friction process. The structural stability of β-Na2Si2O5 and kanemite after the wear test was studied by XRD. It was found that a loss of interlamellar water causes the layer structure of kanemite to collapse during a long-duration wear test. The layered structure of β-Na2Si2O5 is stable, and its tribological properties are better than those of kanemite.
研究领域:
材料科学
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摩擦学
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产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2024
·
IF 9
Haoran Li,Jiahui Ma,Wei Yan,Jingrui Lan,Wenpeng Hong
The lifetime and photovoltaic conversion efficiency of the solar cell will decline as the temperature rises. Herein, a versatile hydrogel allowing atmospheric water harvesting and evaporative cooling is introduced to passively reduce the working temperature of the solar cell. As a flexible substrate, the lithium-rich and highly absorbent polyacrylamide hydrogel is employed to satisfy these specifications. Preferentially, the water-saturated hydrogel, which is bonded to the backside of the solar cell, collects the waste heat produced by the cell and dissipates it into the atmosphere by water evaporation. Importantly, the hydrogel naturally gathers atmospheric vapor at night or on overcast days to revive its cooling ability. This configuration endows the PV cell with a cooling flux of up to 529 W m −2 and thus reduces the working temperature of a polycrystalline silicon cell by 26 °C at 1 sun (=1 kW m −2 ) illumination. More importantly, the hydrogel arrangement supports 6.2 % and 17 % improvements in average open-circuit and maximum power output (or photovoltaic efficiency), respectively. This is devoid of limits on access to liquid water resources, making it a potential option for efficient and sustainable solar cell power generation.
研究领域:
材料科学
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能源技术
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环境工程
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产品关联
DOI
高影响因子
TRIBOLOGY LETTERS
·
2016
·Vol. 64
·期 1
·1-9
·
IF 1.758
Chen Li,Zhang Xiaosheng,Xu Hong,Dong Jinxiang
The tribological properties of α-Zr(HPO 4 )·H 2 O and Cu(OH) 2 Zr(HPO 4 ) 2 ·2H 2 O (α-ZrP and Cu-α-ZrP, respectively) were investigated in lithium grease by using an optimol SRV-V oscillating reciprocating friction and wear tester (SRV). α-ZrP had excellent anti-wear and friction-reducing properties regardless of the applied load, frequency, and test duration. The applied load for α-ZrP reached 600 N, and the corresponding friction coefficient was 0.082. At 60 Hz, the wear volume rate was 11.16 × 10 −9 mm 3 /Nm. The tribological properties of Cu-α-ZrP were dependent on the test conditions, especially at higher frequency. The α-ZrP worn steel surfaces were smooth and shallow as indicated from scanning electron microscopy and a three-dimensional non-contact surface mapping profiler. Related elements were detected by energy-dispersive X-ray spectroscopy on the rubbed surfaces. A boundary solid film may form on the worn surfaces after friction tests. In reciprocating mode, α-ZrP stuck on the contacting surfaces, which enabled it to form a stable solid lubricant film more effectively than Cu-α-ZrP. The crystal structure may be important for film strength under high loads, especially at high speed.
研究领域:
材料科学
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摩擦学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2022
·
IF 3.898
Chen Chen,Yujie Liu,Qiong Tang,Hong Xu,Mingxing Tang,Xuekuan Li,Lei Liu,Jinxiang Dong
A new category of lithium greases was synthesized by using poly- α -olefin (PAO8) and alkyl-tetralin as base oil, where the alkyl-tetralins were synthesized by the alkylation of tetralin and olefins. The influence of thickener concentration, alkyl-tetralin content and type of blend oils on the rheological and tribological performance of lithium grease was investigated. The microstructures of soap fibers were measured to reveal the structure–property correlations. The concentration of thickener and alkyl-tetralin content obviously affect the lubricating performance of lithium grease, while the molecular structure of alkyl-tetralin has no obvious impact on their properties. It was found that alkyl-tetralin could significantly enhance the thickening ability of PAO8 base oils, and decrease the amount of thickeners by 1.5% (mass). Lithium greases prepared using 20% (mass) alkyl-tetralin as co-base oil exhibited high colloidal stability, excellent rheological behaviors and tribological properties.
研究领域:
材料科学
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化学工程
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机械工程
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产品关联
DOI
高影响因子
Natural Sciences
·
2022
·Vol. 3
·期 1
·e20220038
·
IF 0
Chunfeng Li,Quanwen Pan,Wenjun Ying,He Shan,Ruzhu Wang,Hua Zhang,Jiayun Wang
Sorption-based atmospheric water harvesting (SAWH) is a promising technology that can potentially alleviate global shortages of water, especially in arid regions. However, current SAWH devices are difficult to scale up and exhibit significant disadvantages in terms of their cost, portability and efficiency. Herein, we report a portable and efficient atmospheric water-harvesting device with scalable and low-cost high-performance lithium-containing membrane-encapsulated composite sorbents. We use the thermodynamic framework for moist air states to develop the device with a structure featuring hollow insulation grid that harnessed the large temperature difference between the sorbent and the condenser, and thus, the water yield of SAWH device was increased by 20.5%. In outdoor experiments, it achieved an ultra-high water productivity of 34.8 g water /kg device and 1399.28 g water /(m 2 day) and an exceptionally low water-extraction cost of $2.65/kg water per cycle. Thus, this scalable and efficient passive SAWH device demonstrates the possibility of achieving low-cost and reliable water production in real scenarios and paves the way for practical applications of SAWH. Key points Water harvesting cost-efficient sorbent Heat and moisture transfer optimization
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
TRIBOLOGY LETTERS
·
2023
·Vol. 71
·期 4
·1-11
·
IF 3.2
Tang Qiong,Zhao Zhiping,Li Ting,Ge Leizhen,Xu Hong,Liu Lei,Dong Jinxiang
A novel dual-functional group base oil was synthesized by alkylation of methyl oleate from biomass and tetralin from coal chemical industry. Interestingly, the monoalkylated product (MOAT) exhibited low pour point, high flash point, and viscosity index compared with the traditional alkyl aromatic lubricating oil (AN5), owing to the combination of the naphthenic aromatic (tetralin) and the methyl oleate framework. MOAT as co-base oil with PAO8 was studied to prepare lithium-based greases for the first time, and their rheological and tribological properties were evaluated in detail. The microstructure of the MOAT-based grease displayed high entanglement of lithium fiber. The 20% MOAT-based grease markedly reduced friction and wear compared with PAO8-based grease and 20% AN5-based grease. The excellent tribological performances were attributed to the strong interaction between the ester group and the soap fiber that provides more relative elasticity of grease and improves tribological behavior. Our finding clearly demonstrated that MOAT had the potential as a new class of base oil for obtaining high-performance lithium grease. Graphical Abstract
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL LUBRICATION AND TRIBOLOGY
·
2024
·Vol. 76
·期 1
·70-80
·
IF 1.5
Zhicai Du,Qiang He,Hengcheng Wan,Lei Zhang,Zehua Xu,Yuan Xu,Guotao Li
PurposeThis paper aims to improve the tribological properties of lithium complex greases using nanoparticles to investigate the tribological behavior of single additives (nano-TiO2or nano-CeO2) and composite additives (nano-TiO2–CeO2) in lithium complex greases and to analyze the mechanism of their influence using a variety of characterization tools.Design/methodology/approachThe morphology and microstructure of the nanoparticles were characterized by scanning electron microscopy and an X-ray diffractometer. The tribological properties of different nanoparticles, as well as compounded nanoparticles as greases, were evaluated. Average friction coefficients and wear diameters were analyzed. Scanning electron microscopy and three-dimensional topography were used to analyze the surface topography of worn steel balls. The elements present on the worn steel balls’ surface were analyzed using energy-dispersive spectroscopy and X-ray photoelectron spectroscopy.FindingsThe results showed that the coefficient of friction (COF) of grease with all three nanoparticles added was low. The grease-containing composite nanoparticles exhibited a lower COF and superior anti-wear properties. The sample displayed its optimal tribological performance when the ratio of TiO2to CeO2was 6:4, resulting in a 30.5% reduction in the COF and a 29.2% decrease in wear spot diameter compared to the original grease. Additionally, the roughness of the worn spot surface and the maximum depth of the wear mark were significantly reduced.Originality/valueThe main innovation of this study is the first mixing of nano-TiO2and nano-CeO2with different sizes and properties as compound lithium grease additives to significantly enhance the anti-wear and friction reduction properties of this grease. The results of friction experiments with a single additive are used as a basis to explore the synergistic lubrication mechanism of the compounded nanoparticles. This innovative approach provides a new reference and direction for future research and development of grease additives.Peer reviewThe peer review history for this article is available at:https://publons.com/publon/10.1108/ILT-09-2023-0291/
研究领域:
材料科学
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机械工程
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表面工程
✓ 已验证
产品关联
DOI
高影响因子
Scientific Reports
·
2024
·Vol. 14
·期 1
·1-11
·
IF 3.8
Ren Jia,Cai Haopeng,Zhao Gaiqing,Xu Zhuang,Wang Xiaobo
The effects of shear degradation on the microstructures and properties of grease were investigated using a planetary ball mill to simulate a bearing shear zone on grease. The microstructure, cone penetration, colloidal stability, rheological properties noise properties, water washout characteristics and low-temperature torque of lithium grease were characterized. The microstructure of the initial lithium grease is a three-dimensional network structure formed by the uniform fibers. The entanglement level is high. As the ball milling shear time increases, the network structure of lithium grease is destroyed and the fibers are sheared to become short. Eventually all of them become short fibers. The performance test of lithium grease reveal that the cone penetration increases, colloidal stability, structural strength, noise properties, water washout characteristics of lithium grease gradually decreased with the increase of ball milling shear time. Additionally, the low-temperature starting torque and running torque of the grease gradually decrease. This phenomenon occurs due to changes in the microstructure of lithium grease. The shear degradation of lithium grease was mainly divided into two stages: the rapid stage was the destruction of the thickener network structure and the fibers being shortened by shearing. The slow stage was the process in which short fibers were sheared into shorter fibers.
研究领域:
材料科学
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机械工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Chemistry-An Asian Journal
·
2023
·Vol. 18
·期 10
·e202300108
·
IF 4.1
Xiaosheng Zhang,Xiaoqi Xu,Xiaoya Wu,Tao Geng,Xinda Chen,Lei Liu
Graphical A novel layered magnesium phosphate was synthesised via an ionothermal approach, and the crystal structure reveals the formation of an intramolecular bearing with good lubrication behaviour. A novel layered magnesium phosphate (MgP) was synthesised from a MgO−P 2 O 5 -choline chloride-oxalic acid dihydrate system using an ionothermal approach. Single crystal samples of MgP were obtained following introduction of diethylamine (DEA) to the reaction system. Its structure revealed that both the layer and the sheets contained Mg octahedra. Interestingly, adding the layered material to lithium grease resulted in superior lubrication with higher load-carrying, anti-wear and friction reduction capacities compared with the typical lubricant MoS 2 ; the P B value of base grease was increased from 353 to 1078 and 549 N, the wear scar diameter was decreased from 0.50 to 0.34 and 0.46 mm, and the friction coefficient was decreased from 0.082 to 0.056 and 0.075, respectively. We also discuss the lubrication mechanism of layered materials based on the crystal structure and resource endowment. The findings could assist the development of new high-efficiency solid lubricants.
研究领域:
材料科学
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化学工程
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机械工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）