Tribology Letters最新文献

{"title":"Experimental Evidence of High-Acceleration Influence on Friction Force in Tangential Contacts","authors":"Marc Favier,&nbsp;Xinxin Liao,&nbsp;Paolo Germano,&nbsp;Yves Perriard","doi":"10.1007/s11249-026-02174-5","DOIUrl":"10.1007/s11249-026-02174-5","url":null,"abstract":"<div><p>Tribology plays a crucial role in the design of mechanical systems relying on friction to operate. As an example of those systems, ultrasonic ceramic actuators (UCMs) are a type of piezoelectric actuators that leverage the non-linear relationship between friction and relative velocity to drive objects over millimetre ranges using ultrasonic microscopic oscillations of their crystal. The contact dynamics of those actuators are characterised by small relative displacements at high frequency, leading to acceleration up to 50,000 ms⁻². Although mentions are made about the implications of high accelerations in the field of tribology, state-of-the-art analytical models fail to grasp the full range of dynamics. This study aims at exploring the friction force between surfaces having relative motion matching the one occurring inside UCMs. To do so, a custom sliding test bench generates displacement at various high accelerations using impacts from an air piston. The experimental findings show the evolution of tangential friction force versus relative velocity curves as acceleration increases when it comes to values up to 1 ms⁻¹ and 11,000 ms⁻². Analytical and empirical models fail to maintain accuracy across the full range of measured accelerations. Using the dataset that we created, we propose a deep learning approach outperforming the two analytical models used for comparison.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02174-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148465120","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":"Voltage-Driven Growth of Phosphorus Tribofilms","authors":"Yun Zhao,&nbsp;Jie Zhang,&nbsp;Hugh A. Spikes,&nbsp;Janet S. S. Wong","doi":"10.1007/s11249-026-02173-6","DOIUrl":"10.1007/s11249-026-02173-6","url":null,"abstract":"<div><p>Ashless phosphorus-based lubricant additives, which are increasingly deployed in next-generation formulations, often suffer from slow tribofilm formation and poor film stability, limiting their effectiveness under demanding operating conditions. As mechanical systems become increasingly electrified, understanding how lubricants respond to electrical stimuli and developing strategies that exploit such stimuli have become critical for ensuring reliable operation. Here, we investigate the tribological performance of bis(2-ethylhexyl) phosphite (BEPite) in polyalphaolefin (PAO2) lubricated, electrified steel/steel contacts. Current is kept low to limit current-induced effects. Compared to an unbiased surface, BEPite produces thicker and denser tribofilms on anodic rubbing surfaces as voltage increases. This enhancement, however, is only observed when sliding is present. Chemical analysis reveals the presence of oxidised PO₃²⁻-related species and abundant iron in the tribofilm. Static electrochemical cell experiments show surface oxidation is enhanced on anodic surfaces. This suggests voltage-driven triboelectrochemical oxidation and reaction promote tribofilm formation. Either iron oxides or released Fe ions may alter the tribofilm structure. These phenomena appear general for phosphorus-based ashless additives, as both phosphites and phosphates with different structures have seen increased tribofilm growth at anodic rubbing surface. This work demonstrates that an applied voltage, coupled with sliding, can intensify triboelectrochemical reactions, providing new insights for the design of next-generation lubricants.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13341739/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148410109","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":"Influence of Citric Acid on the Friction and Lubrication Characteristics of Human Tooth Enamel at Different pH Levels","authors":"Zhaoxia Bing,&nbsp;Haijing Wang,&nbsp;Xiaolei Fan,&nbsp;Yan Wang,&nbsp;Jiawen Guo","doi":"10.1007/s11249-026-02175-4","DOIUrl":"10.1007/s11249-026-02175-4","url":null,"abstract":"<div><p>The chemical environment in the oral cavity significantly influences the structural degradation of tooth enamel, particularly in tribocorrosive conditions. This study explores the dual influence of citric acid on the wear and erosion behavior of human tooth enamel, focusing on the interaction between lubrication and corrosion effects. Reciprocating sliding tests were performed in citric acid solutions with different pH values and in distilled water. The coefficient of friction, depth of wear scar, static erosion depth, demineralization rate, total enamel loss, and subsurface nanohardness were evaluated. The results showed that citric acid solutions reduced the coefficient of friction compared with distilled water, with the lowest COF values observed at pH 6.2 and 7.0. Except for the pH 2.5 group, the depth of the wear scar in citric acid solutions was lower than that in distilled water, suggesting a citrate-related lubricating effect. However, under strongly acidic conditions, hydrogen ions promoted severe enamel demineralization and static erosion, resulting in hardness reduction and increased total enamel loss. A dynamic competition was observed between citrate-related lubrication and hydrogen ion-induced corrosion, with the balance between these processes determined by their relative concentrations. Higher citrate concentrations promoted faster adsorption and shorter running-in periods, enhancing lubrication, while stronger acidic conditions accelerated enamel dissolution. These findings contribute to a deeper understanding of the tribocorrosive processes affecting tooth enamel, offering valuable insights into the interplay between lubrication and corrosion in biological systems, with potential applications for the development of materials and strategies to mitigate wear and degradation in various biological and engineering contexts.</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 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148465265","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":"Novel Materials Discovery via High-Throughput Automated Tribological Testing of Thin Films","authors":"Tomas F. Babuska,&nbsp;Kyle Dorman,&nbsp;Justin M. Hall,&nbsp;Manish Jain,&nbsp;Michael T. Dugger,&nbsp;Brandon A. Krick,&nbsp;Filippo Mangolini,&nbsp;Frank W. DelRio,&nbsp;David P. Adams,&nbsp;Brad L. Boyce,&nbsp;John F. Curry","doi":"10.1007/s11249-026-02171-8","DOIUrl":"10.1007/s11249-026-02171-8","url":null,"abstract":"<div><p>High-throughput automated testing offers accelerated ways to discover and characterize novel tribological materials. Here, we describe the design of a custom, fully automated, parallelized ball-on-flat reciprocating tribometer capable of performing upward of 1000 friction experiments a day depending on contact conditions. Combinatorial physical vapor deposition was utilized to develop 448 Pt–Au alloy coatings spanning the full binary compositional range. Tribological performance was evaluated in both lab air and dry nitrogen environments, revealing multiparametric dependencies of friction on composition, hardness, reduced modulus, surface roughness, and sputtered atom kinetic energy. In dry nitrogen, ultralow friction coefficients (<i>µ</i>_ss &lt; 0.1) were observed for Pt-rich coatings, with friction strongly influenced by both composition and the kinetic energy of Pt atoms during deposition. The low friction behavior in dry <i>N</i>₂, attributed to the formation of tribofilms on Pt–Au, highlights the role of deposition conditions on surface tribochemical processes. Lab air sliding experiments showed large variations in friction coefficients (~ 0.2 to 1) across the entire compositional range and no trends with other modalities or modeled deposition atomistics. Benefits of adapting automation and/or parallelization to reduce operator and testing time were explored by calculating the total times for the presented dataset. Systems with parallelized friction probes as well as automated systems are shown to reduce operator time by 99% and testing time by 90% compared to conventional serial testing. This work demonstrates the power of high-throughput tribological methods to generate large, multimodal datasets, paving the way toward self-driving laboratories in tribology that combine mechanistic insights and machine learning-driven materials optimization.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02171-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148465002","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":"Tribological Performance of Phosphorus- and Sulfur-Containing Antiwear Additives Under High Vacuum Conditions","authors":"Takashi Yokoyama,&nbsp;Kazuaki Maniwa,&nbsp;Koji Matsumoto,&nbsp;Saiko Aoki","doi":"10.1007/s11249-026-02172-7","DOIUrl":"10.1007/s11249-026-02172-7","url":null,"abstract":"<div><p>Future space missions, such as lunar exploration, will require lubricants with enhanced antiwear performance and extended operational lifetimes compared with currently available space lubricants. To address this challenge, this study investigates the applicability of widely used phosphorus- and sulfur-containing antiwear additives under high-vacuum conditions for space lubricants. However, the performance and tribochemical behavior of such additives under vacuum conditions lacking oxygen and moisture remain insufficiently understood. In this work, nine antiwear additives containing phosphorus and/or sulfur were dissolved in poly-α-olefin (PAO) base oil, and sliding tests were performed under oil-immersed conditions in both air and high-vacuum conditions. Although most additives exhibited increased wear under vacuum, some additives maintained stable antiwear performance despite the absence of atmospheric oxygen and moisture. The tribochemical behavior on the sliding surfaces was analyzed by energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) to elucidate the underlying tribochemical mechanisms. The results suggest that, under the present test conditions, the acidic phosphate ester with saturated alkyl chains maintained antiwear performance under vacuum, and sulfur-containing species may contribute to the protection of fresh surfaces in oxygen-deficient environments. Furthermore, the tribofilm compositions were found to differ between air and vacuum conditions. These findings provide useful implications for further studies on the molecular design of lubricants for future space missions.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380973","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":"Experimental Study on Roll Wear Behavior and Fractal Modeling Under Hot Rolling Conditions","authors":"Sunrui Tao,&nbsp;Caiyi Liu,&nbsp;Silvia Barella,&nbsp;Ruowei Li,&nbsp;Shuo Guo,&nbsp;Shicheng Liang,&nbsp;Yan Peng,&nbsp;Ce Ji,&nbsp;Andrea Gruttadauria,&nbsp;Marco Belfi,&nbsp;De Li,&nbsp;Marwan Abdelwahed,&nbsp;Carlo Mapelli","doi":"10.1007/s11249-026-02166-5","DOIUrl":"10.1007/s11249-026-02166-5","url":null,"abstract":"<div><p>To investigate the wear behavior of work rolls under hot rolling conditions, an experimental wear-testing apparatus capable of controlling load, slip ratio, cyclic temperature variation, and cooling was developed. The evolution of the friction coefficient and surface damage during rolling was systematically examined, while fractal theory was employed to characterize the evolution of surface morphology. The results reveal that abrasive wear and surface mechanical damage dominate during the initial stage, whereas oxidation-assisted and adhesive wear gradually become more significant with increasing rolling time because of the repeated formation and fracture of oxide layers. The formation of the oxide film may help reduce direct metal-to-metal contact and alleviate material removal. However, repeated cracking and spallation under coupled thermal and mechanical loading progressively weaken its protective effect. Under intensified thermo-mechanical loading, unstable oxide layers tend to undergo severe spallation, which is associated with accelerated surface degradation. A coupled wear model incorporating thermal, mechanical, and oxidation effects was established to describe the wear evolution, and the predicted results show reasonable agreement with the experimental observations. Sensitivity analysis further indicates that the fractal parameters D and G play important roles in wear evolution, while thermal and oxidation-related parameters also affect the wear process through coupled interactions. These findings provide useful insights into the wear evolution of work rolls under hot rolling conditions.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323238","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":"In-Orbit Experiments and Ground Simulation Studies of Space Solid Lubrication Materials: A Review","authors":"Wei Xiong,&nbsp;Menghao Sun,&nbsp;Xionglong Yin,&nbsp;Jiao Xu","doi":"10.1007/s11249-026-02160-x","DOIUrl":"10.1007/s11249-026-02160-x","url":null,"abstract":"<div><p>With the rapid development of space engineering, the in-orbit service life and reliability of spacecraft have become core issues. The stable operation of precision moving components relies heavily on the performance of lubricating materials under complex space conditions. This review summarizes the effects of the in-orbit environment on typical solid lubricant thin films and the progress of ground-based experimental studies. First, the challenges imposed by the space environment on traditional solid lubricants are described, emphasizing the necessity of ground simulations. Next, representative international in-orbit tribology platforms—including ESA’s TriboLAB, NASA’s MISSE series, JAXA’s ExHAM, and the extravehicular exposure facilities of the Chinese Space Station—are highlighted alongside ex situ analysis methods. Then, ground-based simulation techniques are reviewed, covering vacuum tribometers with in situ coupled irradiation and multi-factor sequential experiments, while analyzing material behavior under simulated atomic oxygen, ultraviolet, and high-energy particles. Finally, future directions are proposed: developing simulation platforms with multi-environment coupling and in situ monitoring, establishing calibration systems between ground and in-orbit tests, and designing intelligent lubricants with attributes such as low-friction, high radiation resistance, ultra-long lifetime, and self-healing performance.</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 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323245","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":"Residual Stress Transition During High-Velocity Particle Impact on Rough Surfaces","authors":"Mingjie Liu,&nbsp;He Zhu,&nbsp;Yanwei Liu,&nbsp;Jianqiao Hu","doi":"10.1007/s11249-026-02162-9","DOIUrl":"10.1007/s11249-026-02162-9","url":null,"abstract":"<div><p>High-velocity particle impact is a fundamental process in contact mechanics, underlying techniques such as cold spray and surface peening. This study investigates particle impact on randomly rough surfaces using finite element simulation. Results show that surface roughness intensifies plastic deformation, reduces bonding threshold, and increases substrate residual stress by up to 21%. A crucial mechanistic transition is identified that particle residual stress shifts from hardening-dominated to thermal-softening-dominated regimes as velocity increases, with a critical dimensionless velocity around 0.30. Through dimensional analysis, a theoretical power-law model is developed and validated against simulations, describing the velocity dependence as <span>({sigma}_{r}propto {V}_{i}^{1})</span> below and <span>({sigma}_{r}propto {V}_{i}^{-1})</span> above the critical velocity. This model provides a practical tool for residual stress control in tribological applications involving high-velocity contact and interfacial adhesion.</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 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323087","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 Separation and Interfacial Stiffness of Elastoplastic Contact of Self-Affine Fractal Rough Surfaces","authors":"J. F. Cheng,&nbsp;X. M. Liang,&nbsp;G. F. Wang","doi":"10.1007/s11249-026-02170-9","DOIUrl":"10.1007/s11249-026-02170-9","url":null,"abstract":"<div><p>Finite element simulations were performed to investigate elastoplastic contact of self-affine fractal rough surfaces. The effects of yield strain, hardening exponent, and Hurst exponent on pressure distribution, separation distribution, mean separation, and interfacial stiffness were examined. The load-separation relation is well described by a piecewise function, including a complementary error function branch at light loads and an exponential branch at intermediate loads. More importantly, after normalization by a reference load scale, both the load-separation and stiffness-load relations collapse onto nearly unified curves, indicating that material hardening and surface morphology mainly rescale the load level rather than changing the basic contact response. Stronger hardening enhances near-contact elastic coupling, increases the probability of small positive separations, and reduces the mean separation. These results provide a unified scaling picture for interpreting separation and stiffness in elastoplastic rough contact.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148281605","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":"Non-equilibrium Molecular Dynamics Study of the Tribological Behavior of Lubricated Amorphous Carbon","authors":"Rebeca Q. Stelle,&nbsp;Roberto Gomes de Aguiar Veiga,&nbsp;Marcio G. Di V. Cuppari","doi":"10.1007/s11249-026-02155-8","DOIUrl":"10.1007/s11249-026-02155-8","url":null,"abstract":"<div><p>Non-equilibrium molecular dynamics (NEMD) simulations were carried out to investigate the lubrication of two amorphous carbon surfaces by a confined fluid of n-hexadecane molecules. Interatomic interactions were described by the AIREBO-M potential. An external pressure of 1 GPa and shear rates in the range of <span>(10^9)</span>–<span>(10^{10})</span> s<span>(^{-1})</span> were applied to the system. Subjected to this high shear rates, above the critical shear rate, the n-hexadecane fluid behaved as a non-Newtonian fluid. Slip-boundary behavior was not observed, but the system demonstrated shear localization. Due to stronger interactions at the solid–lubricant interface, where some n-hexadecane molecules were adsorbed, the corresponding sublayers of lubricant molecules moved with the same velocity of the sliding surfaces. Away from the interfaces, a linear velocity profile, consistent with Couette flow, developed towards the center of the fluid channel. The friction coefficients calculated from the mean shear stresses were in the ultra-low friction region, which is compatible with experimental data for similar tribosystems.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02155-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148281071","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}