Tribology Letters最新文献

{"title":"Sliding Friction of Hard Sliders on Rubber: Theory and Experiment","authors":"R. Xu,&nbsp;B. N. J. Persson","doi":"10.1007/s11249-025-02064-2","DOIUrl":"10.1007/s11249-025-02064-2","url":null,"abstract":"<div><p>We present a study of sliding friction for rigid triangular steel sliders on soft rubber substrates under both lubricated and dry conditions. For rubber surfaces lubricated with a thin film of silicone oil, the measured sliding friction at room temperature agrees well with theoretical predictions obtained from a viscoelastic model originally developed for rolling friction. On the lubricated surface, the sliding friction is primarily due to bulk viscoelastic energy dissipation in the rubber. The model, which includes strain-dependent softening of the rubber modulus, accurately predicts the experimental friction curves. At lower temperatures (<span>(T = -20^circ textrm{C})</span> and <span>(-40^circ textrm{C})</span>), the measured friction exceeds the theoretical prediction. We attribute this increase to penetration of the lubricant film by surface asperities, leading to a larger adhesive contribution. For dry surfaces, the adhesive contribution becomes dominant. By subtracting the viscoelastic component inferred from the lubricated case, we estimate the interfacial frictional shear stress. This shear stress increases approximately linearly with the logarithm of the sliding speed, consistent with stress-augmented thermal activation mechanisms.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-025-02064-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073659","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":"Achieving Ultra-Low Friction in Ti-6Al-4 V Alloy: Hydration Lubrication Mechanisms of HEC-Glycerol Composite","authors":"Dezun Sheng,&nbsp;Hongliang Yu,&nbsp;Xiao Zhang,&nbsp;Xin Zhou","doi":"10.1007/s11249-025-02068-y","DOIUrl":"10.1007/s11249-025-02068-y","url":null,"abstract":"<div><p>Reducing alloy friction to achieve ultra-low friction is a valuable approach to save energy and reduce pollution from oil use, which is a major challenge for researchers. This study introduces a successful method to achieve ultra-low friction in Ti-6Al-4 V using a hydrated lubricant composed of hydroxyethyl cellulose (HEC). And the effects of speed and concentration on lubricating were investigated. It was found that excessive sliding speeds may lead to lubricant detachment and consequent friction increase, indicating that the adsorption ability of HEC needs to be enhanced in future studies. In addition, when the concentration exceeds 5 wt%, wear loss tends to stabilize across tests with different concentrations, while the friction force increases with rising concentrations. Based on these findings, microscopic studies were conducted to investigate the mechanism of friction reduction. Notably, distinct topographic features resembling ‘valleys’ and ‘plateaus’ were identified on the wear scars in a nanoscale scope. The movement of the surfaces induces the hydrated HEC lubricant to flow from the lower valleys to the higher plateaus, suggesting elastohydrodynamic lubrication mechanisms to form robust films. The valleys serve as lubricant reservoirs, while the plateau tops support the lubricant films to prevent contacts between Ti-6Al-4 V and Si₃N₄. The schematic illustrations depict the microscopic mechanisms for achieving of ultra-low friction on Ti-6Al-4 V alloy.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073660","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":"Laser-Induced Fluorescence (LIF) Method-Based Research on the Influence of Textured Water-Lubricated UHMWPE Bearing Tribological Performance","authors":"Haixian Song,&nbsp;Haideng Mu,&nbsp;Dequan Zhu,&nbsp;Quan Zheng,&nbsp;Fuming Kuang","doi":"10.1007/s11249-025-02070-4","DOIUrl":"10.1007/s11249-025-02070-4","url":null,"abstract":"<div><p>The surface texturing of water-lubricated ultra-high molecular weight polyethylene (UHMWPE) bearing has the advantages of enhancing the hydrodynamic effect, capturing wear debris, reducing secondary friction, and storing water, and is one of the research hotspots in tribology. However, the influence of the surface texture of water-lubricated UHMWPE bearing on the friction performance of bearing is still unclear. Based on the laser induced fluorescence (LIF) method, this study developed an in situ-visualization observation system for water film on the friction interface of non-metallic bearing with the help of transparent glass friction pair. The typical textures with different area ratios, aspect ratios and distribution angles were used as the research objects. The water film thickness, friction coefficient and surface morphology of the friction interface of UHMWPE bearing with different textures under low-speed and heavy-load conditions were analyzed. The results show that elongated textures with a reasonable area ratio and length-to-width ratio, arranged along the direction of friction, are more likely to form hydrodynamic effects and create strong support points at the friction interface. Additionally, the divergent and convergent spaces formed at the inlet and outlet of the textured units cause the lubrication pressure at the inlet to be lower than that at the outlet, resulting in severer wear at the inlet compared to the outlet. The overall trends and the mechanism discussed in this research may be considered as a guideline for the design and optimization of surface texture of water-lubricated UHMWPE bearing.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037426","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":"Effects of High-Temperature Annealing on the Frictional Properties of Graphene","authors":"Wenjie He,&nbsp;Yu Zhang,&nbsp;Qiang He,&nbsp;Wen Wang","doi":"10.1007/s11249-025-02065-1","DOIUrl":"10.1007/s11249-025-02065-1","url":null,"abstract":"<div><p>Due to the high surface-to-volume ratio, micro/nano-electromechanical systems (MEMS/NEMS) undergo severe wear during the relative sliding. Graphene, possessing excellent mechanical, physical, and chemical properties, can achieve an ultralow friction and wear state, making it highly promising for significantly minimizing friction and wear in MEMS/NEMS. However, graphene films used in MEMS/NEMS are typically subjected to thermal annealing pretreatment during the fabrication process. To maintain optimal performance, it is particularly necessary to investigate the evolution of graphene tribological properties after high-temperature annealing. In this article, by performing nanoscale atomic force microscopy (AFM) measurements on mechanically exfoliated graphene, we reveal that the friction force on graphene decreases slightly upon annealing to approximately 200 °C, then gradually increases before rising rapidly once the annealing temperature exceeds 500 °C. Raman spectroscopy identifies that the changes in friction result from the annealing-induced compressive stress accumulation and defects creation. Our results provide deep insights for the application of graphene in sliding MEMS/NEMS.</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":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037137","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 Reduction Behavior of Polyacrylic Acid Solutions Driven by Molecular Structure and Adsorption Stability","authors":"Cheng Zheng,&nbsp;Jimin Xu,&nbsp;Haiyang Gu,&nbsp;Lin Sun,&nbsp;Juchen Zhang,&nbsp;Kun Liu,&nbsp;Tomoko Hirayama","doi":"10.1007/s11249-025-02066-0","DOIUrl":"10.1007/s11249-025-02066-0","url":null,"abstract":"<div><p>In the context of low-viscosity aqueous lubrication, this study systematically investigates the lubrication mechanisms of polyacrylic acid (PAA) solutions. It combines experimental techniques with molecular dynamics simulations to elucidate the effects of concentration-dependent molecular structures and temperature-dependent adsorption stability. Results show that with increasing PAA concentration, the friction coefficient first decreases and then increases, with optimal lubrication observed at 0.2%. Higher concentrations lead to increased PAA adsorption, elevated acidity, and molecular aggregation, resulting in surface corrosion and intensified wear. At high temperatures, while adsorption energy remains stable, enhanced chain flexibility and entanglement raise viscosity, reduce film fluidity, and accelerate wear. These findings provide valuable insights for optimizing water-based lubrication systems using PAA additives.</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":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021492","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":"Enhanced Tribological Modelling of Violin Rosin","authors":"Jim Woodhouse,&nbsp;Paul Galluzzo","doi":"10.1007/s11249-025-02062-4","DOIUrl":"10.1007/s11249-025-02062-4","url":null,"abstract":"<div><p>Accurate simulation of the motion of a bowed violin string requires a reliable tribological model for rosin, with which the bow-hairs are coated. None of the models proposed in the past have given entirely satisfactory results. An enhanced model is proposed here, which combines influences from the contact temperature and the sliding speed. Transient vibration predictions using this model are compared with earlier experimental measurements in the “Guettler diagram”, demonstrating better agreement than with earlier models.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-025-02062-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929411","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":"On the Dependence of Static Friction Coefficient on Normal Load","authors":"Michele Ciavarella","doi":"10.1007/s11249-025-02061-5","DOIUrl":"10.1007/s11249-025-02061-5","url":null,"abstract":"<div><p>In recent interesting experiments, Peng et al. ((2015) PRL, 134, 176202) have shown that the static friction coefficient in a spherical contact drops of a factor close to 2 over 3 decades of increase of normal load, converging to a dynamic friction coefficient. The difference is larger than what commonly attributed in dry metals. They have interpreted this with a numerical boundary integral contact calculations involving many asperities using two input parameters (a static and a dynamic friction coefficient from AFM experiments at nanoscale). However, we show that similar drop with normal load is also expected from the theory of \"Griffith\" or \"JKR\" friction (Ciavarella (2015) J Mech Phys Solids 84: 313–324) which has the advantage of being a simple analytical theory and also of being closely connected with friction laws used commonly today in geophysics. Further, it also uses two input parameters, and requires no numerical solution of the rough contact problem for the sphere.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-025-02061-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929410","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":"Robustness and Sensitivity of the Λ*-Ratio in Microelastohydrodynamic Lubrication","authors":"Jonny Hansen,&nbsp;Deepak K. Prajapati,&nbsp;Marcus Björling,&nbsp;Roland Larsson","doi":"10.1007/s11249-025-02060-6","DOIUrl":"10.1007/s11249-025-02060-6","url":null,"abstract":"<div><p>This study builds upon the work published by Hansen et al. (Tribol Lett 69:1–17, 2021), which introduced a revised film parameter, <span>({Lambda }^{*}={({h}_{text{m}}+h}_{text{c}}{f}_{text{q}})/Spk)</span>, for evaluating rough surface contacts in the microelastohydrodynamic (micro-EHL) and mixed lubrication (ML) regimes. The parameter incorporates a micro-EHL correction term (<span>({f}_{text{q}})</span>) that accounts for different roughness lays (or pattern), the reduced peak height parameter (<span>(Spk)</span>) for more relevant roughness representation, and an updated criterion for the EHL-to-ML transition (<span>({Lambda }^{*}=1)</span>). These advancements address the limitations of the traditional <span>(Lambda)</span>-ratio by offering improved sensitivity to running-in wear, resilience to measurement artefacts, and more realistic predictions of lubrication quality. In the present study, we investigate how measurement and calculation methods influence the robustness and sensitivity of the <span>({Lambda }^{*})</span>-ratio. Key considerations include the impact of spatial resolution from surface roughness measurements, the sensitivity of asperity summit radius calculation methods, and the use of amplitude reduction theory (ART) as an alternative approach to compute <span>({Lambda }^{*})</span> and benchmark its performance. Within the given scope, the results show that spatial biases can be mitigated with appropriate filter sizes and that <span>({Lambda }^{*})</span> consistently predicts the EHL–ML transition more accurately than the traditional Λ-ratio, regardless of the asperity radius method used. Furthermore, we found that while ART can be used to compute <span>({Lambda }^{*})</span>, the original approach using the <span>({f}_{text{q}})</span>-term offers both overall improved accuracy and simplicity. By critically assessing key uncertainties with <span>({Lambda }^{*})</span>, this study strengthens the parameter's robustness and enhances its applicability as a reliable tool for analysing and designing tribological systems.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-025-02060-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929412","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":"Scratch Behavior of Micro-Patterned Polymeric Surfaces","authors":"Sumit Khatri,&nbsp;Shuang Xiao,&nbsp;Hongming Guo,&nbsp;Hung-Jue Sue","doi":"10.1007/s11249-025-02063-3","DOIUrl":"10.1007/s11249-025-02063-3","url":null,"abstract":"<div><p>Polymers are inherently scratch-sensitive due to their ease of deformation and damage. Polycarbonate (PC) offers excellent optical clarity and mechanical resilience, yet has limited engineering usage due to its vulnerability to surface scratching. Utilizing patterned surfaces while maintaining transparency is a viable strategy to achieve improved scratch resistance of PC. In this study, effect of micro-imprinted surface patterns, specifically, 10 µm holes and pillars, on the frictional and scratch behavior of PC was investigated using a combined experimental and finite element methods (FEM) approach. Standardized scratch tests (ASTM D7027-20/ISO 19252:08) and high-resolution confocal microscopy were chosen to assess damage resistance, while the dynamic stress distribution and contact area evolution during scratching were captured via FEM. Results demonstrate that hole-patterned surfaces exhibit superior scratch resistance compared to pillar-patterned and flat surfaces. This improvement is attributed to the reduction in contact area, lower coefficient of friction, and a possible “air cushion” effect generated by the trapped air within the holes, which provides additional resistance. Although pillar structures initially reduce the friction coefficient, they are prone to early mechanical failure due to stress concentration. This study presents a predictive mechanistic framework that extends the existing literature by incorporating fluid–structure interaction effects, offering a promising avenue for designing scratch-resistant polymers.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927049","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":"The Influence of Lubricant Formulation on Surface Damage Under Electrified Rolling-Sliding Contact with Relevance to Electric Vehicle Drivetrain Applications","authors":"Jaewoo Oh,&nbsp;Ammad Yousuf,&nbsp;Hugh Spikes,&nbsp;Amir Kadiric","doi":"10.1007/s11249-025-02059-z","DOIUrl":"10.1007/s11249-025-02059-z","url":null,"abstract":"<div><p>Surface damage due to electric potential is one of the primary reliability concerns for electric vehicle drive units. This paper for the first time identifies specific lubricant components which promote such damage. The work can help design new e-Fluids that improve EV reliability. Recent experimental studies have shown substantial effects of electric potential across a lubricated contact on contact friction and surface damage; these studies primarily used either pure base oil or fully formulated commercial lubricants. However, the specific behavior of key additive components, such as friction modifiers (FMs), under electric fields remains poorly understood. In this study, a series of model fluids consisting of base oil and single FMs of different types was systematically designed to isolate the effects of individual additives. Friction and wear properties under DC electric field (2 V and &lt;50 mA) and mixed lubrication conditions were comparatively evaluated using a ball on disc tribometer, suitably modified to apply electric potential across the contact. While base oil alone and base oil +MoDTC solution exhibited only mild surface damage, all six solutions tested containing organic friction modifiers (OFMs) showed pronounced groove wear on the cathodic side. Among these, OFMs with amino group (–NH₂), such as oleylamine (OAm), led to the highest friction and wear increase under electrified conditions. A fully formulated e-Fluid containing OAm as a FM exhibited a similar surface damage pattern, despite the presence of other additives in the formulation. Interestingly, this characteristic response was substantially mitigated when the amino group (–NH₂) was replaced with a dimethyl-amino group, –N(CH₃)₂, suggesting that the chemical reactivity and/or steric hindrance of the OFM polar head play a crucial role in the observed phenomena. Based on experimental findings, the underlying wear mechanism is postulated to be electrochemical polishing, a type of corrosive-abrasive wear. It is speculated that OFMs electrochemically react on cathodic metal(oxide) surfaces in the presence of oxygen, promoted by an applied electric field, to form a thin and soft layer that is easily abraded by the oxidized anode surface. This study provides valuable insights into designing electrically robust e-Fluids with desirable tribological properties to improve reliability and efficiency of modern EV drivetrains.</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":"73 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-025-02059-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918534","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}