1
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Sang X, Han K, Zhu M, Ma L. Friction Reduction Achieved by Ultraviolet Illumination on TiO 2 Surface. Materials (Basel) 2024; 17:1680. [PMID: 38612193 PMCID: PMC11012504 DOI: 10.3390/ma17071680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/08/2023] [Accepted: 11/24/2023] [Indexed: 04/14/2024]
Abstract
Controlling friction by light field is a low-cost, low-energy, non-polluting method. By applying ultraviolet light on the surface of photosensitive materials, the properties of the friction pairs or lubricant can be influenced, thus achieving the purpose of reducing friction. In this study, TiO2, an inorganic photosensitive material, was selected to investigate the modulating effect of light fields on friction lubrication when using polyalphaolefin (PAO) base oil as a lubricant, and the modulation law of light fields on the friction lubrication behavior was investigated under different loads (1-8 N), different speeds (20-380 mm/s), and different viscosities (10.1-108.6 mPa·s) of PAO base oil. The experimental results showed that light treatment could reduce the friction coefficient of PAO4 base oil lubrication from 0.034 to 0.016, with a reduction of 52.9% under conditions of 3 N-load and 56.5 mm/s-speed, and the best regulation effect could be achieved under the mixed lubrication condition. After TiO2 was treated with ultraviolet light, due to its photocatalytic property, PAO molecules were oxidized and adsorbed on the TiO2 surface to form an adsorption layer, which avoided the direct contact of rough peaks and thus reduced the friction coefficient. This study combines photosensitivity, photocatalysis, and friction, presenting a method to reduce the friction coefficient by applying a light field without changing the friction pairs or lubricants, which provides a new direction for friction modulation and gives new ideas for practical applications.
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Affiliation(s)
| | | | | | - Liran Ma
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China; (X.S.); (K.H.); (M.Z.)
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2
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Zhang Q, Zhang G, Huang Y, He S, Li Y, Jin L, Han J. Surface-Modified LDH Nanosheets with High Dispersibility in Oil for Friction and Wear Reduction. ACS Appl Mater Interfaces 2024; 16:5316-5325. [PMID: 38227431 DOI: 10.1021/acsami.3c17322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Surface and interfacial engineering of nanomaterials is essential for improving dispersion stability in liquids. In this study, we report that oleic acid (OA)- and stearic acid (SA)-functionalized layered double hydroxide (LDH) nanosheets as lubricant additives can achieve high dispersion and reduce friction and wear. LDH is a typical layered structure, and OA and SA are long-chain organic molecules that are not only compatible with base oils but also act as friction-reducing agents. The OA and SA molecules were branched onto ZnMgAl LDH nanosheets using dehydration condensation between the exposed OH groups on the surface of LDH and the COOH groups on the OA and SA molecules. Compared with that of the pristine ZnMgAl LDH, the dispersion of OA-ZnMgAl LDH and SA-ZnMgAl LDH was significantly improved. The surface-modified LDH exhibited superior tribological properties and great stability due to the synergistic lubrication effect between OA, SA, and LDH. Even at an ultralow concentration (0.15 wt %), the coefficient of friction and wear volume were reduced by ∼65 and ∼99%, respectively, compared to those of the base oil. Due to the green and simple synthesis method and excellent tribological properties, surface-functionalized LDH has enormous possibilities for future industrial applications.
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Affiliation(s)
- Qiang Zhang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- Quzhou Institute for Innovation in Resource Chemical Engineering, Quzhou 324000, Zhejiang Province, China
| | - Guiju Zhang
- Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Yongwang Huang
- Tianjin Nisseki Lubricants & Grease Co., Ltd., Binhai New Area, Tianjin 300480, China
| | - Shan He
- Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Yong Li
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lan Jin
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jingbin Han
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- Quzhou Institute for Innovation in Resource Chemical Engineering, Quzhou 324000, Zhejiang Province, China
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3
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Liu S, Hu G, Wang Y, Liu S, Ye Q, Zhou F, Liu W. Hybrid Carbon Nanospheres with Encapsulated (Bi)Metallic Nanocrystals as Lubricant Additives for Antiwear and Friction Reduction. ACS Appl Mater Interfaces 2024; 16:3911-3921. [PMID: 38197650 DOI: 10.1021/acsami.3c17100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Herein, the novel core-shell organo-inorganic hybrid carbon nanospheres with encapsulated ultrafine bimetal nanocrystals were successfully prepared by a one-pot domino drive synthesis combined with postcarbonization. The excellent properties of the metals such as high strength and thermal conductivity are retained, and the poor dispersion of the metal in the oil could be improved by encapsulating the metal in organic-inorganic hybrid carbon nanospheres. The vanadium and wolframium nanocrystals embedded in nitrogen-doped carbon nanospheres (V/W@NCNs) manifested remarkable oil dispersity on account of the lipophilic organic phase of the carbon shell. It is worth noting that the as-obtained V/W@NCNs display better tribological properties compared with the base oil, such as a higher extreme pressure of 1250 N, a lower friction coefficient of about 0.09, and a significant reduction in wear volume of 91.5%, which are attributed to the robust protective film that was formed on the surface of the friction pair through mechanical deposition and physical and tribochemical reaction during the friction process.
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Affiliation(s)
- Sha Liu
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Guanghao Hu
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Yixin Wang
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Shujuan Liu
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Qian Ye
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Feng Zhou
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Weimin Liu
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
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4
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Xu S, Pham DT, Su S. Robotized unplugging of a cylindrical peg press-fitted into a cylindrical hole. R Soc Open Sci 2024; 11:230872. [PMID: 38298397 PMCID: PMC10827423 DOI: 10.1098/rsos.230872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024]
Abstract
It is well accepted that remanufacturing, the returning of a product that has reached the end of its service life to its original condition, is economically and environmentally beneficial. Robotizing disassembly can make remanufacturing even more cost-effective by removing a substantial proportion of the labour costs associated with dismantling end-of-life products for subsequent processing. As unplugging of press-fitted components is a common operation in disassembly, it is appropriate to investigate how it can be robotized. This paper discusses an unplugging technique, twist-and-pull or twisting-pulling, to reduce the axial frictional resistance during the unplugging process and enable a robot to perform it easily. Through theoretical modelling, simulations, and experimental analysis, the paper explores the interaction between twisting, pulling and axial friction reduction during unplugging. Analysis of the experimental, simulation and theoretical results has confirmed that for a small radial interference, twist-and-pull reduces the axial friction and the maximum required unplugging force.
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Affiliation(s)
- Shuihao Xu
- Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Duc Truong Pham
- Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Shizhong Su
- Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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5
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Gaudiuso C, Volpe A, Mezzapesa FP, Putignano C, Ancona A. Tailoring the Coefficient of Friction by Direct Laser Writing Surface Texturing. Micromachines (Basel) 2023; 15:7. [PMID: 38276835 PMCID: PMC10819829 DOI: 10.3390/mi15010007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 01/27/2024]
Abstract
The modification of the surface topography at the micro- and nanoscale is a widely established as one of the best ways to engineering the surface of materials, to improve the tribological performances of materials in terms of load capacity and friction. The present paper reviews the state of the art on laser surface texturing by exploiting the technique of direct laser writing for tailoring the coefficient of friction, highlighting the effect of the textures' arrangement on the lubricated conformal and non-conformal contact behavior.
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Affiliation(s)
- Caterina Gaudiuso
- CNR IFN Institute for Photonics and Nanotechnologies, Via Amendola 173, 70126 Bari, Italy; (A.V.); (F.P.M.); (A.A.)
| | - Annalisa Volpe
- CNR IFN Institute for Photonics and Nanotechnologies, Via Amendola 173, 70126 Bari, Italy; (A.V.); (F.P.M.); (A.A.)
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari e Politecnico di Bari, Via Amendola 173, 70126 Bari, Italy;
| | - Francesco Paolo Mezzapesa
- CNR IFN Institute for Photonics and Nanotechnologies, Via Amendola 173, 70126 Bari, Italy; (A.V.); (F.P.M.); (A.A.)
| | - Carmine Putignano
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari e Politecnico di Bari, Via Amendola 173, 70126 Bari, Italy;
- Department of Mechanics, Mathematics and Management, Politecnico di Bari, Viale Japigia 182, 70126 Bari, Italy
| | - Antonio Ancona
- CNR IFN Institute for Photonics and Nanotechnologies, Via Amendola 173, 70126 Bari, Italy; (A.V.); (F.P.M.); (A.A.)
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari e Politecnico di Bari, Via Amendola 173, 70126 Bari, Italy;
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6
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Kerr A, Häkkinen S, Hall SCL, Kirkman P, O’Hora P, Smith T, Kinane CJ, Caruana A, Perrier S. Anchor Group Bottlebrush Polymers as Oil Additive Friction Modifiers. ACS Appl Mater Interfaces 2023; 15:48574-48583. [PMID: 37811661 PMCID: PMC10591277 DOI: 10.1021/acsami.3c12628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 09/21/2023] [Indexed: 10/10/2023]
Abstract
Surface-tethered polymers have been shown to be an efficient lubrication strategy for boundary and mixed lubrication by providing a solvated film between solid surfaces. We have assessed the performance of various graft copolymers as friction modifier additives in oil and revealed important structure-property relationships for this application. The polymers consisted of an oil-soluble, grafted poly(lauryl acrylate) segment and a polar, linear poly(4-acryloylmorpholine) anchor group. Reversible addition-fragmentation chain transfer polymerization was used to access various architectures with control of the grafting density and position of the anchor group. Macrotribological studies displayed promising results with ≈50% reduction in friction coefficient at low polymer treatment rates. QCM-D experiments, neutron reflectometry, small-angle neutron scattering, and atomic force microscopy were used to gather detailed information on these polymers' surface adsorption characteristics, film structure, and solution behavior.
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Affiliation(s)
- Andrew Kerr
- Department
of Chemistry, The University of Warwick, Coventry CV4 7AL, U.K.
| | - Satu Häkkinen
- Department
of Chemistry, The University of Warwick, Coventry CV4 7AL, U.K.
| | - Stephen C. L. Hall
- Department
of Chemistry, The University of Warwick, Coventry CV4 7AL, U.K.
| | - Paul Kirkman
- Lubrizol
Limited, The Knowle, Nether Lane, Hazelwood DE56 4AN, Derbyshire, U.K.
| | - Paul O’Hora
- Lubrizol
Limited, The Knowle, Nether Lane, Hazelwood DE56 4AN, Derbyshire, U.K.
| | - Timothy Smith
- Lubrizol
Limited, The Knowle, Nether Lane, Hazelwood DE56 4AN, Derbyshire, U.K.
| | - Christian J. Kinane
- Rutherford
Appleton Laboratory, ISIS Neutron and Muon
Sourcey, Didcot OX11 0QX, U.K.
| | - Andrew Caruana
- Rutherford
Appleton Laboratory, ISIS Neutron and Muon
Sourcey, Didcot OX11 0QX, U.K.
| | - Sébastien Perrier
- Department
of Chemistry, The University of Warwick, Coventry CV4 7AL, U.K.
- Warwick
Medical School, The University of Warwick, Coventry CV4 7AL, U.K.
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7
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Grützmacher PG, Cutini M, Marquis E, Rodríguez Ripoll M, Riedl H, Kutrowatz P, Bug S, Hsu CJ, Bernardi J, Gachot C, Erdemir A, Righi MC. Se Nanopowder Conversion into Lubricious 2D Selenide Layers by Tribochemical Reactions. Adv Mater 2023; 35:e2302076. [PMID: 37247210 DOI: 10.1002/adma.202302076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/10/2023] [Indexed: 05/30/2023]
Abstract
Transition metal dichalcogenide (TMD) coatings have attracted enormous scientific and industrial interest due to their outstanding tribological behavior. The paradigmatic example is MoS2 , even though selenides and tellurides have demonstrated superior tribological properties. Here, an innovative in operando conversion of Se nanopowders into lubricious 2D selenides, by sprinkling them onto sliding metallic surfaces coated with Mo and W thin films, is described. Advanced material characterization confirms the tribochemical formation of a thin tribofilm containing selenides, reducing the coefficient of friction down to below 0.1 in ambient air, levels typically reached using fully formulated oils. Ab initio molecular dynamics simulations under tribological conditions reveal the atomistic mechanisms that result in the shear-induced synthesis of selenide monolayers from nanopowders. The use of Se nanopowder provides thermal stability and prevents outgassing in vacuum environments. Additionally, the high reactivity of the Se nanopowder with the transition metal coating in the conditions prevailing in the contact interface yields highly reproducible results, making it particularly suitable for the replenishment of sliding components with solid lubricants, avoiding the long-lasting problem of TMD-lubricity degradation caused by environmental molecules. The suggested straightforward approach demonstrates an unconventional and smart way to synthesize TMDs in operando and exploit their friction- and wear-reducing impact.
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Affiliation(s)
- Philipp G Grützmacher
- Institute for Engineering Design and Product Development, Tribology Research Division, TU Wien, Vienna, 1060, Austria
| | - Michele Cutini
- Department of Physics and Astronomy, Alma Mater Studiorum - University of Bologna, Bologna, 40127, Italy
| | - Edoardo Marquis
- Department of Physics and Astronomy, Alma Mater Studiorum - University of Bologna, Bologna, 40127, Italy
| | | | - Helmut Riedl
- Institute of Materials Science and Technology, TU Wien, Vienna, 1060, Austria
| | - Philip Kutrowatz
- Institute of Materials Science and Technology, TU Wien, Vienna, 1060, Austria
| | - Stefan Bug
- Institute for Engineering Design and Product Development, Tribology Research Division, TU Wien, Vienna, 1060, Austria
| | - Chia-Jui Hsu
- Institute for Engineering Design and Product Development, Tribology Research Division, TU Wien, Vienna, 1060, Austria
| | - Johannes Bernardi
- University Service Centre for Transmission Electron Microscopy (USTEM), TU Wien, Vienna, 1040, Austria
| | - Carsten Gachot
- Institute for Engineering Design and Product Development, Tribology Research Division, TU Wien, Vienna, 1060, Austria
| | - Ali Erdemir
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Maria Clelia Righi
- Department of Physics and Astronomy, Alma Mater Studiorum - University of Bologna, Bologna, 40127, Italy
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8
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Ramezani M, Ripin ZM, Jiang CP, Pasang T. Superlubricity of Materials: Progress, Potential, and Challenges. Materials (Basel) 2023; 16:5145. [PMID: 37512418 PMCID: PMC10386490 DOI: 10.3390/ma16145145] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/16/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023]
Abstract
This review paper provides a comprehensive overview of the phenomenon of superlubricity, its associated material characteristics, and its potential applications. Superlubricity, the state of near-zero friction between two surfaces, presents significant potential for enhancing the efficiency of mechanical systems, thus attracting significant attention in both academic and industrial realms. We explore the atomic/molecular structures that enable this characteristic and discuss notable superlubric materials, including graphite, diamond-like carbon, and advanced engineering composites. The review further elaborates on the methods of achieving superlubricity at both nanoscale and macroscale levels, highlighting the influence of environmental conditions. We also discuss superlubricity's applications, ranging from mechanical systems to energy conservation and biomedical applications. Despite the promising potential, the realization of superlubricity is laden with challenges. We address these technical difficulties, specifically those related to achieving and maintaining superlubricity, and the issues encountered in scaling up for industrial applications. The paper also underscores the sustainability concerns associated with superlubricity and proposes potential solutions. We conclude with a discussion of the possible future research directions and the impact of technological innovations in this field. This review thus provides a valuable resource for researchers and industry professionals engaged in the development and application of superlubric materials.
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Affiliation(s)
- Maziar Ramezani
- Department of Mechanical Engineering, Auckland University of Technology, Auckland 1010, New Zealand
| | - Zaidi Mohd Ripin
- School of Mechanical Engineering, Universiti Sains Malaysia, Nibong Tebal 14300, Malaysia
| | - Cho-Pei Jiang
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
| | - Tim Pasang
- Department of Manufacturing and Mechanical Engineering Technology, Oregon Institute of Technology, Klamath Falls, OR 97601, USA
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9
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Xia Y, Lu Y, Yang G, Chen C, Hu X, Song H, Deng L, Wang Y, Yi J, Wang B. Application of Nano-Crystalline Diamond in Tribology. Materials (Basel) 2023; 16:2710. [PMID: 37049004 PMCID: PMC10096283 DOI: 10.3390/ma16072710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/04/2023] [Accepted: 03/13/2023] [Indexed: 06/19/2023]
Abstract
Nano-crystalline diamond has been extensively researched and applied in the fields of tribology, optics, quantum information and biomedicine. In virtue of its hardness, the highest in natural materials, diamond outperforms the other materials in terms of wear resistance. Compared to traditional single-crystalline and poly-crystalline diamonds, nano-crystalline diamond consists of disordered grains and thus possesses good toughness and self-sharpening. These merits render nano-crystalline diamonds to have great potential in tribology. Moreover, the re-nucleation of nano-crystalline diamond during preparation is beneficial to decreasing surface roughness due to its ultrafine grain size. Nano-crystalline diamond coatings can have a friction coefficient as low as single-crystal diamonds. This article briefly introduces the approaches to preparing nano-crystalline diamond materials and summarizes their applications in the field of tribology. Firstly, nano-crystalline diamond powders can be used as additives in both oil- and water-based lubricants to significantly enhance their anti-wear property. Nano-crystalline diamond coatings can also act as self-lubricating films when they are deposited on different substrates, exhibiting excellent performance in friction reduction and wear resistance. In addition, the research works related to the tribological applications of nano-crystalline diamond composites have also been reviewed in this paper.
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Affiliation(s)
- Yue Xia
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yunxiang Lu
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Guoyong Yang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Chengke Chen
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiaojun Hu
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Hui Song
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Lifen Deng
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yuezhong Wang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Jian Yi
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Bo Wang
- Chair of Functional Materials, Department of Materials Science & Engineering, Saarland University, 66123 Saarbrücken, Germany
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10
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Söderfjäll M, Gachot C. Friction Reduction by Dimple Type Textured Cylinder Liners-An Experimental Investigation. Materials (Basel) 2023; 16:665. [PMID: 36676417 PMCID: PMC9863613 DOI: 10.3390/ma16020665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Applying texture to a surface in a tribological interface will influence frictional performance, which has been investigated in several previous studies. However, since varying operating conditions heavily affect the frictional performance and optimum texture dimensions, more work in this field is required. There are few experimental studies concerning the influence of texture on friction especially under sliding lubricated conditions and even fewer at high sliding speeds. In this work, the effect of texture on frictional losses between the piston ring and cylinder liner is studied experimentally. The texture is of the dimple type, with a diameter and depth of 300 µm and 3 µm, respectively, applied to the cylinder liner surface. Experiments are performed with sliding speeds close to real piston sliding speeds. A clear reduction in frictional losses is observed with the textured cylinder liner. Moreover, qualitatively comparing the experimental results to a numerical model shows a good correlation.
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Affiliation(s)
- Markus Söderfjäll
- Division of Machine Elements, Luleå University of Technology, 97187 Luleå, Sweden
| | - Carsten Gachot
- Tribology Research Group, Vienna University of Technology, 1040 Vienna, Austria
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11
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Bhaumik S, Paleu V, Chowdhury D, Batham A, Sehgal U, Bhattacharya B, Ghosh C, Datta S. Tribological Investigation of Textured Surfaces in Starved Lubrication Conditions. Materials (Basel) 2022; 15:8445. [PMID: 36499941 PMCID: PMC9738694 DOI: 10.3390/ma15238445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/18/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
The present work investigates the friction reduction capability of two types of micro-textures (grooves and dimples) created on steel surfaces using a vertical milling machine. The wear studies were conducted using a pin-on-disc tribometer, with the results indicating a better friction reduction capacity in the case of the dimple texture as compared to the grooved texture. The microscopic images of the pin surface revealed deep furrows and significant damage on the pin surfaces of the groove-textured disc. An optimization of the textured surfaces was performed using an artificial neural network (ANN) model, predicting the influence of the surface texture as a function of the load, depth of cut and distance between the micro-textures.
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Affiliation(s)
- Shubrajit Bhaumik
- Tribology and Interactive Surface Research Laboratory (TRISUL), Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Chennai 601103, India
| | - Viorel Paleu
- Mechanical Engineering, Mechatronics and Robotics Department, Mechanical Engineering Faculty, “Gheorghe Asachi” Technical University of Iași, 63 D. Mangeron Blvd., 700050 Iași, Romania
| | - Dhrubajyoti Chowdhury
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, India
| | - Adarsh Batham
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, India
| | - Udit Sehgal
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, India
| | - Basudev Bhattacharya
- Research and Development and Scientific Services, Tata Steel Limited, Jamshedpur 831001, India
| | - Chiradeep Ghosh
- Research and Development and Scientific Services, Tata Steel Limited, Jamshedpur 831001, India
| | - Shubhabrata Datta
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, India
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12
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Ge X, Chai Z, Shi Q, Liu Y, Tang J, Wang W. Liquid Superlubricity Enabled by the Synergy Effect of Graphene Oxide and Lithium Salts. Materials (Basel) 2022; 15:ma15103546. [PMID: 35629573 PMCID: PMC9143536 DOI: 10.3390/ma15103546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023]
Abstract
In this study, graphene oxide (GO) nanoflakes and lithium salt (LiPF6) were utilized as lubrication additives in ether bond−containing dihydric alcohol aqueous solutions (DA(aq)) to improve lubrication performances. The apparent friction reduction and superlubricity were realized at the Si3N4/sapphire interface. The conditions and laws for superlubricity realization have been concluded. The underlying mechanism was the synergy effect of GO and LiPF6. It was proven that a GO adsorption layer was formed at the interface, which caused the shearing interface to transfer from solid asperities to GO interlayers (weak interlayer interactions), resulting in friction reduction and superlubricity realization. In addition to the GO adsorption layer, a boundary layer containing phosphates and fluorides was formed by tribochemical reactions of LiPF6 and was conducive to low friction. Additionally, a fluid layer contributed to friction reduction as well. This work proved that GO−family materials are promising for friction reduction, and provided new insights into realizing liquid superlubricity at macroscale by combining GO with other materials.
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Affiliation(s)
- Xiangyu Ge
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (X.G.); (Z.C.); (J.T.); (W.W.)
| | - Zhiyuan Chai
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (X.G.); (Z.C.); (J.T.); (W.W.)
| | - Qiuyu Shi
- State Grid Smart Grid Research Institute Co., Ltd., Beijing 102209, China;
| | - Yanfei Liu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (X.G.); (Z.C.); (J.T.); (W.W.)
- Correspondence:
| | - Jiawei Tang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (X.G.); (Z.C.); (J.T.); (W.W.)
| | - Wenzhong Wang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (X.G.); (Z.C.); (J.T.); (W.W.)
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13
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Wei Y, Resendiz J, Tomkowski R, Liu X. An Experimental Study of Micro-Dimpled Texture in Friction Control under Dry and Lubricated Conditions. Micromachines (Basel) 2021; 13:mi13010070. [PMID: 35056235 PMCID: PMC8778524 DOI: 10.3390/mi13010070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 12/29/2021] [Accepted: 12/29/2021] [Indexed: 11/16/2022]
Abstract
Friction control is a vital technology for reaching sustainable development goals, and surface texturing is one of the most effective and efficient techniques for friction reduction. This study investigated the performance of a micro-dimpled texture under varying texture densities and experimental conditions. Reciprocating sliding tests were performed to evaluate the effects of the micro-dimpled texture on friction reduction under different normal loads and lubrication conditions. The results suggested that a micro-dimpled texture could reduce the coefficient of friction (CoF) under dry and lubricated conditions, and high dimple density results in a lower CoF. The dominant mechanism of the micro-dimpled texture’s effect on friction reduction was discussed, and surface observation and simulation suggested that a micro-dimpled texture could reduce the contact area at the friction interface, thereby reducing CoF.
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Affiliation(s)
- Yuan Wei
- Frontiers Science Center for Flexible Electronics, Xi’an Institute of Flexible Electronics (IFE) and Xi’an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Manufacturing and Metrology Systems, KTH Royal Institute of Technology, 10044 Stockholm, Sweden;
- Correspondence: (Y.W.); (X.L.)
| | - Jesus Resendiz
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada;
| | - Robert Tomkowski
- Manufacturing and Metrology Systems, KTH Royal Institute of Technology, 10044 Stockholm, Sweden;
| | - Xu Liu
- School of Mechanical Engineering, Xi’an Aeronautical University, Xi’an 710077, China
- Correspondence: (Y.W.); (X.L.)
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14
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Wos S, Koszela W, Pawlus P. Selected Methods and Applications of Anti-Friction and Anti-Wear Surface Texturing. Materials (Basel) 2021; 14:3227. [PMID: 34207998 DOI: 10.3390/ma14123227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 11/21/2022]
Abstract
The constant development of environmental protection causes the necessity to increase the efficiency of machines. By increasing the efficiency of machines, energy losses can be limited, leading to lower energy consumption. Friction reduction leads to an increase in efficiency and a decrease in wear. In this paper, selected surface texturing methods, such as burnishing and abrasive jet machining, with their limitations are presented. Thanks to those processes, various surface textures can be obtained. Examples of applications of these methods for friction and wear reduction are shown.
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15
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Wang M, Ghosh SK, Stafford CM, Blevins AK, Huang S, Martinez J, Long R, Bowman CN, Killgore JP, Zou M, Ding Y. Snakeskin-Inspired Elastomers with Extremely Low Coefficient of Friction under Dry Conditions. ACS Appl Mater Interfaces 2020; 12:57450-57460. [PMID: 33306352 DOI: 10.1021/acsami.0c18316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Soft elastomers are critical to a broad range of existing and emerging technologies. One major limitation of soft elastomers is the large friction of coefficient (COF) due to inherently large adhesion and internal loss. In applications where lubrication is not applicable, such as soft robotics, wearable electronics, and biomedical devices, elastomers with inherently low dry COF are required. Inspired by the low COF of snakeskins atop soft bodies, this study reports the development of elastomers with low dry COF by growing a hybrid skin layer with a strong interface with a large stiffness gradient. Using a solid-liquid interfacial polymerization (SLIP) process, hybrid skin layers are imparted onto elastomers, which reduces the COF of the elastomers from 1.6 to 0.1, without sacrificing the bulk compliance and ductility of elastomer. Compared with existing surface modification methods, the SLIP process offers spatial control and ability to modify flat, prepatterned, curved, and inner surfaces, which is essential to engineer multifunctional skin layers for emerging applications.
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Affiliation(s)
- Mengyuan Wang
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Sujan K Ghosh
- Department of Mechanical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Christopher M Stafford
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Adrienne K Blevins
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Sijia Huang
- Department of Chemical and Biochemical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Jaylene Martinez
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Rong Long
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Christopher N Bowman
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
- Department of Chemical and Biochemical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Jason P Killgore
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Min Zou
- Department of Mechanical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Yifu Ding
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
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16
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Putignano C, Parente G, Profito FJ, Gaudiuso C, Ancona A, Carbone G. Laser Microtextured Surfaces for Friction Reduction: Does the Pattern Matter? Materials (Basel) 2020; 13:ma13214915. [PMID: 33142947 PMCID: PMC7662309 DOI: 10.3390/ma13214915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/12/2020] [Accepted: 10/19/2020] [Indexed: 11/16/2022]
Abstract
Frictional performances of different textures, including axisymmetric and directional patterns, have been tested in the mixed and the hydrodynamic lubrication regimes. Experimental results, corroborated by numerical simulations, show that the leading parameter is the geometrical pattern void ratio since a large number of dimples offers, at low speed, a trap for debris whereas, at high speed, due to the flow expansion in each micro-hole, fosters a fluid pressure drop, the consequent insurgence of micro-cavitation and, ultimately, the reductions of the shear stresses. Furthermore, in this paper, it is shown that, by means of directional textures, equivalent hydrodynamic wedges can be built up, thus establishing different friction performances depending on the flow direction.
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Affiliation(s)
- Carmine Putignano
- Department of Mechanics, Mathematics and Management, Politecnico di Bari, 70126 Bari, Italy; (G.P.); (G.C.)
- Institute for Photonics and Nanotechnologies-IFN-CNR, U.O.S, Physics Department “M. Merlin”, 70126 Bari, Italy; (C.G.); (A.A.)
- Correspondence:
| | - Giuliano Parente
- Department of Mechanics, Mathematics and Management, Politecnico di Bari, 70126 Bari, Italy; (G.P.); (G.C.)
| | - Francisco Josè Profito
- Department of Mechanical Engineering, Polytechnic School of the University of São Paulo, 01000 São Paulo, Brazil;
| | - Caterina Gaudiuso
- Institute for Photonics and Nanotechnologies-IFN-CNR, U.O.S, Physics Department “M. Merlin”, 70126 Bari, Italy; (C.G.); (A.A.)
| | - Antonio Ancona
- Institute for Photonics and Nanotechnologies-IFN-CNR, U.O.S, Physics Department “M. Merlin”, 70126 Bari, Italy; (C.G.); (A.A.)
| | - Giuseppe Carbone
- Department of Mechanics, Mathematics and Management, Politecnico di Bari, 70126 Bari, Italy; (G.P.); (G.C.)
- Institute for Photonics and Nanotechnologies-IFN-CNR, U.O.S, Physics Department “M. Merlin”, 70126 Bari, Italy; (C.G.); (A.A.)
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17
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Veronesi F, Boveri G, Raimondo M. Amphiphobic Nanostructured Coatings for Industrial Applications. Materials (Basel) 2019; 12:E787. [PMID: 30866464 PMCID: PMC6427180 DOI: 10.3390/ma12050787] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/27/2019] [Accepted: 03/05/2019] [Indexed: 11/17/2022]
Abstract
The search for surfaces with non-wetting behavior towards water and low-surface tension liquids affects a wide range of industries. Surface wetting is regulated by morphological and chemical features interacting with liquid phases under different ambient conditions. Most of the approaches to the fabrication of liquid-repellent surfaces are inspired by living organisms and require the fabrication of hierarchically organized structures, coupled with low surface energy chemical composition. This paper deals with the design of amphiphobic metals (AM) and alloys by deposition of nano-oxides suspensions in alcoholic or aqueous media, coupled with perfluorinated compounds and optional infused lubricant liquids resulting in, respectively, solid⁻liquid⁻air and solid⁻liquid⁻liquid working interfaces. Nanostructured organic/inorganic hybrid coatings with contact angles against water above 170°, contact angle with n-hexadecane (surface tension γ = 27 mN/m at 20 °C) in the 140⁻150° range and contact angle hysteresis lower than 5° have been produced. A full characterization of surface chemistry has been undertaken by X-ray photoelectron spectroscopy (XPS) analyses, while field-emission scanning electron microscope (FE-SEM) observations allowed the estimation of coatings thicknesses (300⁻400 nm) and their morphological features. The durability of fabricated amphiphobic surfaces was also assessed with a wide range of tests that showed their remarkable resistance to chemically aggressive environments, mechanical stresses and ultraviolet (UV) radiation. Moreover, this work analyzes the behavior of amphiphobic surfaces in terms of anti-soiling, snow-repellent and friction-reduction properties-all originated from their non-wetting behavior. The achieved results make AM materials viable solutions to be applied in different sectors answering several and pressing technical needs.
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Affiliation(s)
- Federico Veronesi
- Institute of Science and Technology for Ceramics ISTEC CNR, via Granarolo, 64-48018 Faenza, Italy.
| | - Giulio Boveri
- Institute of Science and Technology for Ceramics ISTEC CNR, via Granarolo, 64-48018 Faenza, Italy.
| | - Mariarosa Raimondo
- Institute of Science and Technology for Ceramics ISTEC CNR, via Granarolo, 64-48018 Faenza, Italy.
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18
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van Ravensteijn BGP, Bou Zerdan R, Seo D, Cadirov N, Watanabe T, Gerbec JA, Hawker CJ, Israelachvili JN, Helgeson ME. Triple Function Lubricant Additives Based on Organic-Inorganic Hybrid Star Polymers: Friction Reduction, Wear Protection, and Viscosity Modification. ACS Appl Mater Interfaces 2019; 11:1363-1375. [PMID: 30525414 DOI: 10.1021/acsami.8b16849] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Polymer-based lubricant additives for friction reduction, wear protection, or viscosity improvement have been widely studied. However, single additives achieving all three functions are rare. To address this need, we have explored the combination of polymer topology with organic-inorganic hybrid chemistry to simultaneously vary the temperature- and shear-dependent properties of polymer additives in solution and at solid surfaces. A topological library of lubricant additives, based on statistical copolymers of stearyl methacrylate and methyl methacrylate, ranging from linear to branched star architectures, was prepared using ruthenium-catalyzed controlled radical polymerization. Control over the polymerization yielded additives with low dispersity and comparable molecular weights, allowing evaluation of the influence of polymer architecture on friction reduction, wear protection, and bulk viscosity improvement in a commercial base oil (Yubase 4). Structure-performance relationships for these functions were assessed by a combination of a high-speed surface force apparatus (HS-SFA) experiments, wear track profilometry, quartz crystal microbalance analysis, and solution viscometry. The custom-built HS-SFA provides a unique experimental environment to measure the boundary lubrication performance under extreme shear rates (≈107 s-1) for prolonged times (24 h), mimicking the extreme conditions of automotive applications. These experiments revealed that the performance of the additives as boundary lubricants and wear protectants scales with the degree of branching. The branched architectures prohibit ordering of the additives in thin films under high-load conditions, leading to a thicker absorbed polymer brush boundary layer and therefore enhanced film fluidity and lubricity. Additionally, star polymers with increasing arm number lead to bulk viscosity modification, reflected by a significant increase in the viscosity index compared to the commercial base oil. Although outperformed by linear polymers for bulk viscosity improvement, the (hybrid) star polymers successfully combine the three distinct lubricant additive functions: friction reduction, wear protection, and bulk viscosity improvement-in a single polymeric structure. It should also be noted that, judging from HS-SFA experiments, hybrid stars carrying a silicate-based core outperform their fully organic analogues as boundary lubricants. The enhanced performance is most likely driven by attractive forces between the silicate cores and the employed metallic surfaces. Combining three function in one minimizes formulation complexity and thus opens a route to fundamentally understand and formulate key design parameters for the development of novel multifunction lubricant additives.
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19
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Abstract
Starch-based emulsion microgel particles with different starch (15 and 20 wt %) and oil contents (0-15 wt %) were synthesized, and their lubrication performance under physiological conditions was investigated. Emulsion microgels were subjected to skin mimicking or oral cavity mimicking conditions, i.e., smooth hydrophobic polydimethylsiloxane ball-on-disc tribological tests, in the absence or presence of salivary enzyme (α-amylase). In the absence of enzyme, emulsion microgel particles (30-60 vol % particle content) conserved the lubricating properties of emulsion droplets, providing considerably lower friction coefficients (μ ≤ 0.1) in the mixed lubrication regime compared to plain microgel particles (0 wt % oil). Upon addition of enzyme, the lubrication performance of emulsion microgel particles became strongly dependent on the particles' oil content. Microgel particles encapsulating 5-10 wt % oil showed a double plateau mixed lubrication regime having a lowest friction coefficient μ ∼ 0.03 and highest μ ∼ 0.1, the latter higher than with plain microgel particles. An oil content of 15 wt % was necessary for the microgel particles to lubricate similarly to the emulsion droplets, where both systems showed a normal mixed lubrication regime with μ ≤ 0.03. The observed trends in tribology, theoretical considerations, and the combined results of rheology, light scattering, and confocal fluorescence microscopy suggested that the mechanism behind the low friction coefficients was a synergistic enzyme- and shear-triggered release of the emulsion droplets, improving lubrication. The present work thus demonstrates experimentally and theoretically a novel biolubricant additive with stimuli-responsive properties capable of providing efficient boundary lubrication between soft polymeric surfaces. At the same time, the additive should provide an effective delivery vehicle for oil soluble ingredients in aqueous media. These findings demonstrate that emulsion microgel particles can be developed into multifunctional biolubricant additives for future use in numerous soft matter applications where both lubrication and controlled release of bioactives are essential.
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20
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Zhao H, Sun Q, Deng X, Cui J. Earthworm-Inspired Rough Polymer Coatings with Self-Replenishing Lubrication for Adaptive Friction-Reduction and Antifouling Surfaces. Adv Mater 2018; 30:e1802141. [PMID: 29862579 DOI: 10.1002/adma.201802141] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/22/2018] [Indexed: 06/08/2023]
Abstract
Earthworms are able to pass through sticky soil without inducing stains through a self-forming thick lubricating layer on their rough skins. To mimic this earthworm-like lubricating capability, an attempt to create a textured structure on the surface of liquid-releasable polymer coatings by a "breath figure" process is described herein. The resulting coatings exhibit fast and site-specific release behavior under external triggers such as solid-based friction. The released oil is then stabilized by the surface texture to form thick lubricating layers, reducing friction and enhancing wear resistance. Moreover, the coatings also exhibit excellent antifouling property in a sticky soil environment. Because the lubricating layer can be regenerated after consumption, the potential of this self-replenished lubricating mechanism in preparing friction-reduction, antiwear, and antifouling coatings used in solid-based environments is therefore envisioned.
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Affiliation(s)
- Huaixia Zhao
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
- INM - Leibniz Institute for New Materials Campus D2 2, Saarbrücken, 66123, Germany
| | - Qiangqiang Sun
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
| | - Xu Deng
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
| | - Jiaxi Cui
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
- INM - Leibniz Institute for New Materials Campus D2 2, Saarbrücken, 66123, Germany
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21
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Abstract
Advanced lubrication is essential in human life for improving mobility, durability, and efficiency. Here we report the synthesis, characterization, and evaluation of two groups of oil-suspendable silver nanoparticles (NPs) as candidate lubricant additives. Two types of thiolated ligands, 4-(tert-butyl)benzylthiol (TBBT) and dodecanethiol (C12), were used to modify Ag NPs in two size ranges, 1-3 and 3-6 nm. The organic surface layer successfully suspended the Ag NPs in a poly-alpha-olefin (PAO) base oil with concentrations up to 0.19-0.50 wt %, depending on the particle type. Use of the Ag NPs in the base oil reduced friction by up to 35% and wear by up to 85% in boundary lubrication. The two TBBT-modified NPs produced a lower friction coefficient than the C12-modified one, while the two larger NPs (3-6 nm) had better wear protection than the smaller one (1-3 nm). Results suggested that the molecular structure of the organic ligand might have a dominant effect on the friction behavior, while the NP size could be more influential in the wear protection. No mini-ball-bearing or surface smoothening effects were observed in the Stribeck scans. Instead, the wear protection in boundary lubrication was attributed to the formation of a silver-rich 50-100 nm thick tribofilm on the worn surface, as revealed by morphology examination and composition analysis from both the top surface and cross section.
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Affiliation(s)
- Chanaka Kumara
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
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22
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Seymour BT, Wright RAE, Parrott AC, Gao H, Martini A, Qu J, Dai S, Zhao B. Poly(alkyl methacrylate) Brush-Grafted Silica Nanoparticles as Oil Lubricant Additives: Effects of Alkyl Pendant Groups on Oil Dispersibility, Stability, and Lubrication Property. ACS Appl Mater Interfaces 2017; 9:25038-25048. [PMID: 28670899 DOI: 10.1021/acsami.7b06714] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This article reports on the synthesis of a series of poly(alkyl methacrylate) brush-grafted, 23 nm silica nanoparticles (hairy NPs) and the study of the effect of alkyl pendant length on their use as oil lubricant additives for friction and wear reduction. The hairy NPs were prepared by surface-initiated reversible addition-fragmentation chain transfer polymerization from trithiocarbonate chain transfer agent (CTA)-functionalized silica NPs in the presence of a free CTA. We found that hairy NPs with sufficiently long alkyl pendant groups (containing >8 carbon atoms, such as 12, 13, 16, and 18 in this study) could be readily dispersed in poly(alphaolefin) (PAO), forming clear, homogeneous dispersions, and exhibited excellent stability at low and high temperatures as revealed by visual inspection and dynamic light scattering studies. Whereas poly(n-hexyl methacrylate) hairy NPs cannot be dispersed in PAO under ambient conditions or at 80 °C, interestingly, poly(2-ethylhexyl methacrylate) hairy NPs can be dispersed in PAO at 80 °C but not at room temperature, with a reversible clear-to-cloudy transition observed upon cooling. High-contact-stress ball-on-flat reciprocating sliding tribological tests at 100 °C showed significant reductions in both the coefficient of friction (up to 38%) and wear volume (up to 90% for iron flat) for transparent, homogeneous dispersions of hairy NPs in PAO at a concentration of 1.0 wt % compared with neat PAO. The formation of a load-bearing tribofilm at the rubbing interface was confirmed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy.
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Affiliation(s)
- Bryan T Seymour
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Roger A E Wright
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Alexander C Parrott
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Hongyu Gao
- Department of Mechanical Engineering, University of California , Merced, California 95343, United States
| | - Ashlie Martini
- Department of Mechanical Engineering, University of California , Merced, California 95343, United States
| | | | - Sheng Dai
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Bin Zhao
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
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23
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Desanker M, Johnson B, Seyam AM, Chung YW, Bazzi HS, Delferro M, Marks TJ, Wang QJ. Oil-Soluble Silver-Organic Molecule for in Situ Deposition of Lubricious Metallic Silver at High Temperatures. ACS Appl Mater Interfaces 2016; 8:13637-13645. [PMID: 27163783 DOI: 10.1021/acsami.6b01597] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A major challenge in lubrication technology is to enhance lubricant performance at extreme temperatures that exceed conventional engine oil thermal degradation limits. Soft noble metals such as silver have low reactivity and shear strength, which make them ideal solid lubricants for wear protection and friction reduction between contacting surfaces at high temperatures. However, achieving adequate dispersion in engine lubricants and metallic silver deposition over predetermined temperatures ranges presents a significant chemical challenge. Here we report the synthesis, characterization, and tribological implementation of the trimeric silver pyrazolate complex, [Ag(3,5-dimethyl-4-n-hexyl-pyrazolate)]3 (1). This complex is oil-soluble and undergoes clean thermolysis at ∼310 °C to deposit lubricious, protective metallic silver particles on metal/metal oxide surfaces. Temperature-controlled tribometer tests show that greater than 1 wt % loading of 1 reduces wear by 60% in PAO4, a poly-α-olefin lubricant base fluid, and by 70% in a commercial fully formulated 15W40 motor oil (FF oil). This silver-organic complex also imparts sufficient friction reduction so that the tribological transition from oil as the primary lubricant through its thermal degradation, to 1 as the primary lubricant, is experimentally undetectable.
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Affiliation(s)
| | | | - Afif M Seyam
- Department of Chemistry, Texas A&M University at Qatar , P.O. Box 23874, Doha, Qatar
| | | | - Hassan S Bazzi
- Department of Chemistry, Texas A&M University at Qatar , P.O. Box 23874, Doha, Qatar
| | - Massimiliano Delferro
- Chemical Sciences and Engineering Division, Argonne National Laboratory , 9700 South Cass Avenue, Lemont, Illinois 60439, United States
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