TRIBOLOGY INTERNATIONAL
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2024
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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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DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 13
·2287
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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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DOI
PubMed
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2024
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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
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DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2022
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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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DOI
高影响因子
INDUSTRIAL LUBRICATION AND TRIBOLOGY
·
2024
·Vol. 76
·期 1
·70-80
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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
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DOI
高影响因子
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