Tribology Letters最新文献

{"title":"Influence of Ambient-Degraded MXene on Rheological and Tribological Behaviour of Synthetic Multigrade Oil","authors":"Nowduru Ravikiran,&nbsp;Swati Singh,&nbsp;Phani Chalapaka,&nbsp;Sanjay R. Dhage,&nbsp;P. K. Jain","doi":"10.1007/s11249-026-02140-1","DOIUrl":"10.1007/s11249-026-02140-1","url":null,"abstract":"<div><p>While two-dimensional Ti₃C₂T_<i>x</i> MXenes demonstrate exceptional tribological potential, their susceptibility to ambient oxidation poses a critical barrier to commercial deployment. The current state of the art predominantly focuses on synthesis ing new MXenes and studying their tribological properties; however, the tribological performance of the inevitably degraded Ti₃C₂T_<i>x</i> MXenes, specifically their interaction (synergism/antagonism) with commercial lubricant additives, remains largely unexplored. This study presents the first systematic evaluation of ambiently degraded Ti₃C₂T_<i>x</i> MXene (aged for 8 weeks) as an additive in commercial 10W30 engine oil. The structural evolution was characterised by oxidation-induced sheet fragmentation and lattice collapse (monitored via XRD, Raman, and SEM), followed by rheological and tribological behaviour across variable concentrations (0.01–0.1 wt.%). Tribological assessments revealed a counterintuitive, non-monotonic concentration dependence. At sub-critical loadings (0.01–0.05 wt.%), the degraded Ti₃C₂T_<i>x</i> MXene nanosheets acted as abrasive third-body agents, exacerbating friction and wear. Conversely, a critical concentration of 0.1 wt.% triggered a mechanistic shift, where the accumulation of degraded Ti₃C₂T_<i>x</i> MXene facilitated the formation of a protective tribofilm, significantly reducing the coefficient of friction and wear despite high sedimentation rates. These findings challenge the paradigm that only pristine nanomaterials are effective, highlighting a complex trade-off between dispersion stability and tribofilm formation. This work provides essential guidelines for defining the functional endurance of Ti₃C₂T_<i>x</i> MXene-based lubricants in real-world engineering environments.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An extended Griffith friction model for the transition to slip in the contact of graded-material spheres","authors":"Shi-Wen Chen,&nbsp;Gang-Feng Wang,&nbsp;Michele Ciavarella","doi":"10.1007/s11249-026-02134-z","DOIUrl":"10.1007/s11249-026-02134-z","url":null,"abstract":"<div><p>In the present paper, we study the role of gradient in the material properties of contacting bodies in the difference between static and kinetic friction for a Hertzian geometry, according to the theory of \"Griffith friction\", for which the transition from stick to slip occurs as an elastic instability. We use the term \"Griffith friction\" to suggest an energy balance approach in mode II to derive stable and unstable equilibrium configurations, where in particular macroscopic sliding can occur by a global elastic instability, analogous to a Griffith crack which doesn’t arrest after reaching a critical size. The most important conclusion are that static friction coefficient: (i) is increased with harder surface; (ii) is increased for small normal loads and tends to infinity in the limit of zero load. These conclusions hold both in the case of a constant frictional fracture energy or a pressure-dependent frictional fracture energy at the interface.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02134-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inlet Pressure and Shear Stress of Elliptical Elastohydrodynamic Contacts","authors":"Wassim Habchi,&nbsp;Scott Bair","doi":"10.1007/s11249-026-02141-0","DOIUrl":"10.1007/s11249-026-02141-0","url":null,"abstract":"<div><p>The inlet pressure in elastohydrodynamic lubrication corresponds to the maximum pressure within the contact inlet, beyond which hydrodynamic effects no longer contribute to film build-up. This quantity is important for properly defining lubricant pressure–viscosity coefficients. The associated inlet shear stress, in turn, is a useful indicator of the validity of the Newtonian assumption. Only recently were inlet pressure and shear stress quantified by the authors for line and circular contacts through numerical simulations, revealing pressures in the range of 50–185 MPa and shear stresses up to 3 MPa, depending on operating conditions. The present work extends this quantification process to wide and slender elliptical contacts. Compared to circular contacts under similar conditions, slender contacts exhibit higher inlet pressures, reaching up to 350 MPa, and shear stresses up to 7 MPa, whereas wide contacts display lower values. The more contact ellipticity deviates from unity (i.e., circular contact), the more pronounced the deviations in both inlet pressure and the corresponding shear stress become, relative to circular contacts. Finally, analytical formulae are provided for evaluating inlet pressure and shear stress as functions of operating conditions, material properties, and contact ellipticity.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Femtosecond Laser-Texturing of a Novel Micro-Texture with Solid Lubricant Additives for Friction Reduction","authors":"Roland Bejjani,&nbsp;Marc Chamoun","doi":"10.1007/s11249-026-02142-z","DOIUrl":"10.1007/s11249-026-02142-z","url":null,"abstract":"<div><p>Femtosecond laser micro-texturing of surfaces has been established as an important technology to reduce frictional losses in lubricated sliding systems. This work differs from previous studies by investigating an optimized micro-texture designed for enhanced hydrodynamic pressure generation combined with graphene and MoS₂ additives to analyze their synergetic friction-reduction mechanism. First, computational fluid dynamics simulations were used to analyze the hydrodynamic pressure build-up and lubricant flow behavior of the micro-texture and film. The simulated lubricant flow pathways also provided insight into the transport of the solid lubricant particles throughout the micro-texture and lubricant film, representing another distinctive aspect of this study. A femtosecond laser was then used to precisely engrave the micro-textures, with optimized process parameters to achieve sharply defined edges, while avoiding thermal damage. Finally, the tribological behavior of the micro-texture was experimentally evaluated using a novel tribometer under different contact pressures, sliding speeds, and solid lubricant additives. When combined with solid lubricant additives, a synergetic friction-reduction effect was observed, attributed to the combined effects of the increase in the film thickness due to hydrodynamic pressure generation, solid lubricant particle retention within the texture and transport throughout the film, forming low-shear tribo-films of solid lubricant additives at the contact interface.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lubrication Performance of Gas–Liquid Two-Phase through Low-Surface-Energy Textures with Bubble Inducing and Stabilizing","authors":"Lixia Xue,&nbsp;Yuanyuan Jiang,&nbsp;Jiujun Xu,&nbsp;Zhijun Yan,&nbsp;Yan Shen","doi":"10.1007/s11249-026-02135-y","DOIUrl":"10.1007/s11249-026-02135-y","url":null,"abstract":"<div><p>Under fluid lubrication conditions, utilizing textures to generate stable gas–liquid two-phase lubrication has emerged as a promising drag reduction approach. A textured surface with both low-surface-energy and bubble induced-stored capability was fabricated by a “one-step” laser method that integrates surface functional layer and texture geometry. By optimizing texture distribution, a stable gas–liquid two-phase layer formed between tribology pairs. Compared with non-texture samples, the texture reduced the maximum friction by up to 61.3%. Furthermore, a dynamic two-phase lubrication model was established through simulation, accounting for oil film thickness variation and clarifying how textures affect fluid pressure distribution and gas entrapment. This work provides fundamental support for the design of friction-reducing morphologies on tribo-pairs, offering an effective solution to mitigate energy dissipation in mechanical friction systems.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Friction Dynamics of Denim Fabrics with Washing or Polishing Treatment","authors":"Rintaro Kawakami,&nbsp;Ken Miyata,&nbsp;Syuji Kobayashi,&nbsp;Mitsumasa Kimata,&nbsp;Yoshimune Nonomura","doi":"10.1007/s11249-026-02143-y","DOIUrl":"10.1007/s11249-026-02143-y","url":null,"abstract":"<div><p>The friction properties between human skin and fabrics are important because they affect the latter’s attractiveness. In this study, we evaluated the friction force on three denim fabrics and cashmere, wool, and cotton fabrics using a sinusoidal motion friction evaluation system that replicates human motion. We analyzed the effects of physical properties (elastic modulus, surface roughness, and thickness) on friction properties. Washing treatment for starch removal reduced the Young’s modulus from 36.6 ± 3.8 kPa to 16.1 ± 0.3 kPa and increased the friction coefficient from 0.28 ± 0.01 to 0.30 ± 0.01. After the fabric was polished, the Young’s modulus decreased to 8.3 ± 1.0 kPa and the friction coefficient increased to 0.33 ± 0.01. The friction coefficients of the denim, cashmere, wool, and cotton fabrics increased as their Young’s modulus decreased. Therefore, washing and polishing treatments soften denim, increase the real contact area between the contact probe and the fibers, and increase friction resistance. These findings are useful for controlling tactile textures and developing more attractive denim fabrics.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polymer Brush-Enhanced Extraction and Spreading of Oil from Lubricating Greases","authors":"Luciana Buonaiuto,&nbsp;Vincent Siekman,&nbsp;Sander Reuvekamp,&nbsp;Piet M. Lugt,&nbsp;Frieder Mugele","doi":"10.1007/s11249-026-02138-9","DOIUrl":"10.1007/s11249-026-02138-9","url":null,"abstract":"<div><p>Grease lubrication is among the oldest and most widely employed strategies for reducing friction in tribological contacts. Nevertheless, important microscopic mechanisms that govern the release and transport of lubricants in, say, rolling bearings remain poorly understood. Here, we show how the release of lubricating oil from grease reservoirs and its subsequent spreading toward the rolling contact can be controlled by different treatments of the underlying surface. We demonstrate that smooth, flat oxide surfaces, where oil films are stabilized exclusively by molecular wetting forces, are unable to extract and spread appreciable amounts of oil. In contrast, functionalizing the surface by topographic roughening and/or by coatings of swelling oleophilic polymer brushes can enhance the oil extraction by over two orders of magnitude. Specifically, polymer brushes with an intrinsic phase transition are shown to enable an adaptive lubrication scheme, where the amount of lubricant provided increases rapidly when the temperature rises beyond the melting temperature of the surface-grafted polymer coating.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02138-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147643111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Synergistic Effect of DLC Coating and Diketone/Nanocopper Hybrid Additive in Marine Engine Oil","authors":"Yuwen Xu,&nbsp;Yan Yang,&nbsp;Haonan Zeng,&nbsp;Jingsi Wang,&nbsp;Dan Jia,&nbsp;Tobias Amann,&nbsp;Chengqing Yuan,&nbsp;Ke Li","doi":"10.1007/s11249-026-02130-3","DOIUrl":"10.1007/s11249-026-02130-3","url":null,"abstract":"<div><p>To enhance the boundary lubrication of the cylinder liner-piston ring, this study developed a diketone/nanocopper hybrid additive and investigated its interaction with reactive and non-reactive sliding surfaces. Compared to steel/steel contacts, the hybrid additive performed more effectively in the case of steel/DLC configuration. On the one hand, the lower surface energy of DLC led to a more substantial orientation effect of diketone, resulting in an elevated capacity for forming a lubricant film; on the other hand, the high hardness and chemically inert characteristics of DLC promoted the tribochemical polishing effect of diketone, resulting in a very smooth sliding interface. Based on the synergistic effect between DLC coating and the hybrid additive, a novel lubrication system with superior performance was established for marine engines.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sliding Onset of a Rigid Cylinder in Adhesive Contact with a Deformable Substrate","authors":"Jin-Shan He,&nbsp;Gan-Yun Huang","doi":"10.1007/s11249-026-02139-8","DOIUrl":"10.1007/s11249-026-02139-8","url":null,"abstract":"<div><p>Understanding the transition from contact to sliding at adhesive interfaces represents a fundamental challenge in tribology. Due to the lack of knowledge on the underlying microscopic mechanisms governing sliding onset, large-scale molecular dynamics (MD) simulations have been carried out in the present work to obtain the detailed process for sliding initiation. Nucleation of dislocation like defects has been discovered. Theoretical efforts have been made to characterize the nucleation and hence the static friction. Results reveal that tangential instability and dislocation nucleation compete to dominate the interfacial sliding onset.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multi-scale Interfacial Investigation of Organic Friction Modifiers in Hydrocarbon","authors":"David Burgess,&nbsp;Peter J. Fryer,&nbsp;Ian McRobbie,&nbsp;Jacqueline Reid,&nbsp;Zhenyu Jason Zhang","doi":"10.1007/s11249-026-02137-w","DOIUrl":"10.1007/s11249-026-02137-w","url":null,"abstract":"<div><p>To link molecular characteristics and lubrication performance of Organic Friction Modifiers (OFMs), a multi-scale study was carried out to investigate the effects of functional groups and solvents on the tribological properties of two model OFMs, namely palmitic acid and pentadecylamine. It was observed that the solvent composition has a profound effect on the surface adsorption and the interfacial adhesion force of the OFMs, showing vastly different values of adsorption kinetics and surface coverage. It must be highlighted that the presence of water within the hydrocarbon has a considerable impact on the lubrication performance of OFMs. We were able to quantitatively correlate the molecular properties such as binding force and adsorption kinetics of the OFM with their macroscopic testing results satisfactorily, suggesting that the static Coefficient of Friction (COF) is governed by the properties of the film formed in a thermodynamic equilibrium, whilst the dynamic COF is related to the interfacial forces at the surface during sliding, and finally the wear on the solid surface is related to ability of the OFMs to rapidly re-adsorb on the solid substrate once removed.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13050767/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147631913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}