The behavior of lubricants under sub-nanometer confinement remains poorly understood, limiting insight into fundamental lubrication processes. In this work, we employ molecular dynamics simulations to investigate the lubrication behavior of two-dimensional (2D) and three-dimensional (3D) water under such extreme confinement using a simplified model. We show that 3D water can reduce the coefficient of friction (COF) to below 0.01. In this regime, the wall shear stress is linearly related to the diffusion coefficient perpendicular to the shear direction but independent of the lattice structure. The lubricating effect of water is dominated by pressure. When water is compressed into a 2D state, it exhibits distinct stick‑slip‑like characteristics, leading to an increased COF above 0.02, which is influenced by both pressure and solid lattice structure. This study provides molecular-level insights into confined water lubrication, advancing the understanding of friction under nanoconfinement conditions.
{"title":"Role of water in lubrication under sub-nano confinement: Insights from molecular dynamics simulation","authors":"Yuhao Wu , Zhaozhe Meng , Liguo Qin , Hui Zhang , Yin Zhang , Guangneng Dong","doi":"10.1016/j.triboint.2026.111808","DOIUrl":"10.1016/j.triboint.2026.111808","url":null,"abstract":"<div><div>The behavior of lubricants under sub-nanometer confinement remains poorly understood, limiting insight into fundamental lubrication processes. In this work, we employ molecular dynamics simulations to investigate the lubrication behavior of two-dimensional (2D) and three-dimensional (3D) water under such extreme confinement using a simplified model. We show that 3D water can reduce the coefficient of friction (COF) to below 0.01. In this regime, the wall shear stress is linearly related to the diffusion coefficient perpendicular to the shear direction but independent of the lattice structure. The lubricating effect of water is dominated by pressure. When water is compressed into a 2D state, it exhibits distinct stick‑slip‑like characteristics, leading to an increased COF above 0.02, which is influenced by both pressure and solid lattice structure. This study provides molecular-level insights into confined water lubrication, advancing the understanding of friction under nanoconfinement conditions.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111808"},"PeriodicalIF":6.1,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1016/j.triboint.2026.111800
Manyu Wang, Bing Wang, Meilin Deng, Pengfei Li
The physical characteristics of gas–solid triboelectric charging under high-speed flows remain poorly understood due to limited direct experimental evidence. In this study, in situ triboelectric current measurements were conducted on a metallic blunt body in a shock-wave wind tunnel. The current signals change from random-like fluctuations at Ma3 to intermittent high-amplitude events at Ma6, and further to amplitude-modulated, non-stationary behavior at Ma8. Statistical analysis and continuous wavelet transform were used to analyze the signal features. The triboelectric current is interpreted as a macroscopic response of stochastic micro-contact events, indicating a transition in the temporal characteristics of the current with increasing inflow velocity, and providing experimental support for mechanistic interpretation of high-speed gas–solid friction.
{"title":"Intense pulses and regime transitions of gas–solid triboelectric currents in high-speed flows","authors":"Manyu Wang, Bing Wang, Meilin Deng, Pengfei Li","doi":"10.1016/j.triboint.2026.111800","DOIUrl":"10.1016/j.triboint.2026.111800","url":null,"abstract":"<div><div>The physical characteristics of gas–solid triboelectric charging under high-speed flows remain poorly understood due to limited direct experimental evidence. In this study, in situ triboelectric current measurements were conducted on a metallic blunt body in a shock-wave wind tunnel. The current signals change from random-like fluctuations at Ma3 to intermittent high-amplitude events at Ma6, and further to amplitude-modulated, non-stationary behavior at Ma8. Statistical analysis and continuous wavelet transform were used to analyze the signal features. The triboelectric current is interpreted as a macroscopic response of stochastic micro-contact events, indicating a transition in the temporal characteristics of the current with increasing inflow velocity, and providing experimental support for mechanistic interpretation of high-speed gas–solid friction.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111800"},"PeriodicalIF":6.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1016/j.triboint.2026.111789
Nicola Zani , Candida Petrogalli , Kang Shu , Angelo Mazzù , Giorgio Donzella
This work presents an integrated experimental–numerical study on the rolling contact fatigue (RCF) behaviour of as-built Laser Powder Bed Fused (L-PBF) 17–4PH stainless steel lubricated with water and oil. Controlled twin-disc tests, finite element analyses and modelling were combined to clarify the influence of lubrication on crack initiation and propagation mechanisms. Water-based lubrication promoted accelerated crack growth due to hydraulic pressurization and enhanced shear stresses, while oil lubrication provided a stable elastohydrodynamic separation, delaying crack initiation and mitigating branching. A novel predictive framework was formulated by incorporating elastohydrodynamic similarity parameters into a generalized crack-growth law, enabling the quantification of mechanical–tribological coupling effects. The proposed model exhibited strong agreement with experimental data (R² = 0.75, RMSE = 0.195), confirming the synergistic contribution of stress intensity and viscous dissipation in controlling fatigue damage evolution. Furthermore, the Failure Assessment Diagram (FAD) methodology was extended to account for finite-life and lubrication effects, successfully delineating the transition from crack arrest to propagation across pressure regimes. The developed approach provides a unified, physically consistent basis for assessing lubrication-dependent fatigue performance in additively manufactured steels, offering enhanced predictive capability for RCF design of AM components.
{"title":"Failure assessment of crack propagation in as-built LPBF 17–4PH stainless steel under rolling contact fatigue","authors":"Nicola Zani , Candida Petrogalli , Kang Shu , Angelo Mazzù , Giorgio Donzella","doi":"10.1016/j.triboint.2026.111789","DOIUrl":"10.1016/j.triboint.2026.111789","url":null,"abstract":"<div><div>This work presents an integrated experimental–numerical study on the rolling contact fatigue (RCF) behaviour of as-built Laser Powder Bed Fused (<span>L</span>-PBF) 17–4PH stainless steel lubricated with water and oil. Controlled twin-disc tests, finite element analyses and modelling were combined to clarify the influence of lubrication on crack initiation and propagation mechanisms. Water-based lubrication promoted accelerated crack growth due to hydraulic pressurization and enhanced shear stresses, while oil lubrication provided a stable elastohydrodynamic separation, delaying crack initiation and mitigating branching. A novel predictive framework was formulated by incorporating elastohydrodynamic similarity parameters into a generalized crack-growth law, enabling the quantification of mechanical–tribological coupling effects. The proposed model exhibited strong agreement with experimental data (R² = 0.75, RMSE = 0.195), confirming the synergistic contribution of stress intensity and viscous dissipation in controlling fatigue damage evolution. Furthermore, the Failure Assessment Diagram (FAD) methodology was extended to account for finite-life and lubrication effects, successfully delineating the transition from crack arrest to propagation across pressure regimes. The developed approach provides a unified, physically consistent basis for assessing lubrication-dependent fatigue performance in additively manufactured steels, offering enhanced predictive capability for RCF design of AM components.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111789"},"PeriodicalIF":6.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1016/j.triboint.2026.111807
Rashed Kaiser, Andreas A. Polycarpou
Space mechanisms face severe tribological challenges in vacuum environments where conventional lubrication fails due to surface activation, evaporation, extreme temperatures, radiation, and long-term maintenance-free operation. Friction and wear are dominated by vacuum-induced failure modes rather than load or speed. This review analyzes key failure mechanisms—adhesion, cold welding, lubricant starvation, cryogenic friction rise, regolith abrasion, and degradation—based on spacecraft anomalies and operational history. Solid lubrication strategies, including lamellar materials, carbon coatings, polymers, soft metals, and composite systems, are evaluated for their ability to mitigate these failures. A failure-mode mapping framework and reliability-centered design approach are proposed to guide material selection and ensure lifetime performance. Practical recommendations aim to enable robust tribosystems for extended space missions.
{"title":"Vacuum tribology in space applications: A review of failure mechanisms, solid lubricants, and reliability-centered design","authors":"Rashed Kaiser, Andreas A. Polycarpou","doi":"10.1016/j.triboint.2026.111807","DOIUrl":"10.1016/j.triboint.2026.111807","url":null,"abstract":"<div><div>Space mechanisms face severe tribological challenges in vacuum environments where conventional lubrication fails due to surface activation, evaporation, extreme temperatures, radiation, and long-term maintenance-free operation. Friction and wear are dominated by vacuum-induced failure modes rather than load or speed. This review analyzes key failure mechanisms—adhesion, cold welding, lubricant starvation, cryogenic friction rise, regolith abrasion, and degradation—based on spacecraft anomalies and operational history. Solid lubrication strategies, including lamellar materials, carbon coatings, polymers, soft metals, and composite systems, are evaluated for their ability to mitigate these failures. A failure-mode mapping framework and reliability-centered design approach are proposed to guide material selection and ensure lifetime performance. Practical recommendations aim to enable robust tribosystems for extended space missions.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111807"},"PeriodicalIF":6.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.triboint.2026.111780
Zhengwei Wang , Zhehao Zhang , Jinghua Li , Yongyong He , Yang Li
Tetrahedral amorphous carbon (Ta-C) coatings are widely utilized for their exceptional hardness and superior wear resistance. However, under high-load sliding conditions, Ta-C coatings are often susceptible to severe spalling failure due to the inherent brittleness and high residual internal stress. To enhance the frictional load-bearing capacity, Ta-C coatings with graded sp³ bonding configurations were fabricated by precisely modulating the substrate bias during filtered cathodic vacuum arc (FCVA) deposition. In this study, three types of gradient structure and three constant structure coatings were prepared for comparative analysis. Compared with the constant structure, the gradient coatings feature multilayered interfaces with continuously transitioning bonding configurations and a high surface sp³ fraction, which leads to higher frictional bearing capacity. Notably, the gradient coating with a surface sp³ fraction of 83.7 % exhibited the highest hardness (55.3 GPa), elastic modulus (476.6 GPa), and optimized toughness and adhesion. Under lubricated sliding at a maximum initial Hertzian contact stress of 1028 MPa, the constant structure coatings suffered from comprehensive delamination. In contrast, the gradient coatings maintained their structural integrity, achieving an ultra-low friction coefficient of 0.033 with negligible wear. Microstructural analysis revealed that superlattice-like multilayer features within the gradient structure promote stress redistribution and crack deflection. This work demonstrates that the synergy of gradient bonding design and multilayer modulation provides an effective strategy to overcome the brittleness and load-bearing limitations of superhard Ta-C coatings in high load applications.
{"title":"Bias-induced sp³ bonding gradient design for enhancing the frictional bearing capacity of superhard Ta-C coating","authors":"Zhengwei Wang , Zhehao Zhang , Jinghua Li , Yongyong He , Yang Li","doi":"10.1016/j.triboint.2026.111780","DOIUrl":"10.1016/j.triboint.2026.111780","url":null,"abstract":"<div><div>Tetrahedral amorphous carbon (Ta-C) coatings are widely utilized for their exceptional hardness and superior wear resistance. However, under high-load sliding conditions, Ta-C coatings are often susceptible to severe spalling failure due to the inherent brittleness and high residual internal stress. To enhance the frictional load-bearing capacity, Ta-C coatings with graded sp³ bonding configurations were fabricated by precisely modulating the substrate bias during filtered cathodic vacuum arc (FCVA) deposition. In this study, three types of gradient structure and three constant structure coatings were prepared for comparative analysis. Compared with the constant structure, the gradient coatings feature multilayered interfaces with continuously transitioning bonding configurations and a high surface sp³ fraction, which leads to higher frictional bearing capacity. Notably, the gradient coating with a surface sp³ fraction of 83.7 % exhibited the highest hardness (55.3 GPa), elastic modulus (476.6 GPa), and optimized toughness and adhesion. Under lubricated sliding at a maximum initial Hertzian contact stress of 1028 MPa, the constant structure coatings suffered from comprehensive delamination. In contrast, the gradient coatings maintained their structural integrity, achieving an ultra-low friction coefficient of 0.033 with negligible wear. Microstructural analysis revealed that superlattice-like multilayer features within the gradient structure promote stress redistribution and crack deflection. This work demonstrates that the synergy of gradient bonding design and multilayer modulation provides an effective strategy to overcome the brittleness and load-bearing limitations of superhard Ta-C coatings in high load applications.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111780"},"PeriodicalIF":6.1,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.triboint.2026.111791
Zihao Mou , Jinyu Yao , Lu Wang , Yangdong He , Bin Zhao , Zhijun Wang , Ying Li , Weiwei Tang , Zhiqiang Jiang , Baogang Wang
Separation and application of immature nanoparticles from the synthesis system of polymeric nanoparticles (PNPs) is a cost-effective route to improve the utilization rate of monomers. Here, for the first time, mature and immature polydopamine nanoparticles (mPNPs and imPNPs) with a total yield of up to 75.7 % were separated from the ammonia-driven synthesis system via centrifugation and dialysis, and further transformed into the polyelectrolyte-modified PNPs (mPPNPs and imPPNPs) in a simple strategy. These PPNPs exhibited respectable colloidal stability and tribological properties as lubricant additives of PEG200. Tribological evaluations reflected that the optimal doses of mPPNPs and imPPNPs are 1.0 wt% and 0.5 wt%, respectively. At these doses, the friction and wear reductions by imPPNPs (38.2 % and 63.7 %) were higher than those of mPPNPs (37.6 % and 61.6 %), which is attributed to the smaller size and higher charge density of imPPNPs than mPPNPs. Moreover, the tribological stability of imPPNPs is better than that of mPPNPs under heavy-load, high-speed, long-duration, and start-stop tests. Potential-controlled friction experiments and wear analyses confirmed that the good adsorption ability of the polyelectrolyte shell, the strong adhesion and chelation effects of polydopamine structures, and the deposition of hybrid tribofilm should be responsible for the robust tribological behaviors of imPPNPs. This study highlights the prospect of imPNPs in tribology, enabling waste-to-resource conversion and providing new insights into green lubrication.
{"title":"Immature polymeric nanoparticles as promising lubricant additives enable robust oil-based lubrication and efficient waste-to-resource conversion","authors":"Zihao Mou , Jinyu Yao , Lu Wang , Yangdong He , Bin Zhao , Zhijun Wang , Ying Li , Weiwei Tang , Zhiqiang Jiang , Baogang Wang","doi":"10.1016/j.triboint.2026.111791","DOIUrl":"10.1016/j.triboint.2026.111791","url":null,"abstract":"<div><div>Separation and application of immature nanoparticles from the synthesis system of polymeric nanoparticles (PNPs) is a cost-effective route to improve the utilization rate of monomers. Here, for the first time, mature and immature polydopamine nanoparticles (mPNPs and imPNPs) with a total yield of up to 75.7 % were separated from the ammonia-driven synthesis system via centrifugation and dialysis, and further transformed into the polyelectrolyte-modified PNPs (mPPNPs and imPPNPs) in a simple strategy. These PPNPs exhibited respectable colloidal stability and tribological properties as lubricant additives of PEG200. Tribological evaluations reflected that the optimal doses of mPPNPs and imPPNPs are 1.0 wt% and 0.5 wt%, respectively. At these doses, the friction and wear reductions by imPPNPs (38.2 % and 63.7 %) were higher than those of mPPNPs (37.6 % and 61.6 %), which is attributed to the smaller size and higher charge density of imPPNPs than mPPNPs. Moreover, the tribological stability of imPPNPs is better than that of mPPNPs under heavy-load, high-speed, long-duration, and start-stop tests. Potential-controlled friction experiments and wear analyses confirmed that the good adsorption ability of the polyelectrolyte shell, the strong adhesion and chelation effects of polydopamine structures, and the deposition of hybrid tribofilm should be responsible for the robust tribological behaviors of imPPNPs. This study highlights the prospect of imPNPs in tribology, enabling waste-to-resource conversion and providing new insights into green lubrication.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111791"},"PeriodicalIF":6.1,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.triboint.2026.111796
Zetong Wang , Yuxuan Sheng , Yuanqi Mai , Xuan Ma , Xing Xu , Bo Li , Chuixiao Li
Ammonia fuel, characterized by its hydrogen-rich and carbon-free properties, has garnered significant attention in the field of engines. However, the incylinder environment generated by the fuel and its combustion products may alter the tribological behavior of the engine, thereby impacting the reliability and durability of critical components such as the cylinder liner-piston ring (CLPR) friction pair. This study establishes an experimental protocol to simulate the degradation of lubricating oil induced by ammonia fuel in engines and to assess the tribological performance of the aged oil. Based on the analysis of lubricating oil properties influenced by ammonia and tribological testing results, the degradation mechanism of lubricating oil and the surface damage mechanism of the cylinder liner caused by ammonia were evaluated. Studies have demonstrated that the presence of ammonia impairs the performance of lubricating oils, including increasing kinematic viscosity and altering the total base number (TBN). Additionally, research highlights that ammonia escape characteristics should be considered a critical factor in investigating the tribological behavior of CLPR in ammonia engines. This study offers an exploratory reference for the design of experimental protocols related to the tribological behavior of CLPR in ammonia engines.
{"title":"Influence of ammonia on lubricant degradation and tribological behavior of cylinder liner piston ring system","authors":"Zetong Wang , Yuxuan Sheng , Yuanqi Mai , Xuan Ma , Xing Xu , Bo Li , Chuixiao Li","doi":"10.1016/j.triboint.2026.111796","DOIUrl":"10.1016/j.triboint.2026.111796","url":null,"abstract":"<div><div>Ammonia fuel, characterized by its hydrogen-rich and carbon-free properties, has garnered significant attention in the field of engines. However, the incylinder environment generated by the fuel and its combustion products may alter the tribological behavior of the engine, thereby impacting the reliability and durability of critical components such as the cylinder liner-piston ring (CLPR) friction pair. This study establishes an experimental protocol to simulate the degradation of lubricating oil induced by ammonia fuel in engines and to assess the tribological performance of the aged oil. Based on the analysis of lubricating oil properties influenced by ammonia and tribological testing results, the degradation mechanism of lubricating oil and the surface damage mechanism of the cylinder liner caused by ammonia were evaluated. Studies have demonstrated that the presence of ammonia impairs the performance of lubricating oils, including increasing kinematic viscosity and altering the total base number (TBN). Additionally, research highlights that ammonia escape characteristics should be considered a critical factor in investigating the tribological behavior of CLPR in ammonia engines. This study offers an exploratory reference for the design of experimental protocols related to the tribological behavior of CLPR in ammonia engines.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111796"},"PeriodicalIF":6.1,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.triboint.2026.111793
Jian Pu , Xing Peng , Ruijuan Liu , Shu Yang , Yali Zhang , Xiaogang Zhang , Chao Zhang , Jian Song , Zhongmin Jin
Implantation of artificial hip joints frequently induces local inflammatory responses, resulting in the accumulation of reactive oxygen species (ROS) such as H₂O₂ in peri-prosthetic fluid. These species critically affect fretting corrosion at the femoral head–neck interface. In this study, the fretting corrosion behavior of a CoCrMo–Ti6Al4V alloy pair was examined under simulated inflammatory conditions by introducing H₂O₂. A running condition fretting map (RCFM) was established, identifying three fretting regimes: partial slip (PSR), mixed fretting (MFR), and gross slip (GSR). Compared with normal physiological conditions, the presence of H₂O₂ markedly accelerated corrosion and aggravated material degradation across all regimes. The damage mechanisms of the Ti6Al4V–CoCrMo pair vary significantly across different regimes: abrasive wear and tribocorrosion dominate in PSR; adhesive wear and intensified tribocorrosion occur in MFR; and in GSR, severe abrasive wear, tribocorrosion were observed. Increasing H₂O₂ concentration enhanced thermodynamic stability but intensified corrosion kinetics. Concurrently, the dominant damage mechanism transitions from abrasive wear to tribocorrosion characterized by spallation. These collectively lead to a marked increase in material loss and metal ion release. Overall, H₂O₂ promotes cathodic depolarization and the formation of mechanically unstable oxide films, thereby strengthening corrosion-wear synergy and exacerbating material damage under inflammatory conditions.
{"title":"Influence of inflammatory environment on the fretting corrosion of CoCrMo–Ti6Al4V alloy pairs at the hip head–neck interface","authors":"Jian Pu , Xing Peng , Ruijuan Liu , Shu Yang , Yali Zhang , Xiaogang Zhang , Chao Zhang , Jian Song , Zhongmin Jin","doi":"10.1016/j.triboint.2026.111793","DOIUrl":"10.1016/j.triboint.2026.111793","url":null,"abstract":"<div><div>Implantation of artificial hip joints frequently induces local inflammatory responses, resulting in the accumulation of reactive oxygen species (ROS) such as H₂O₂ in peri-prosthetic fluid. These species critically affect fretting corrosion at the femoral head–neck interface. In this study, the fretting corrosion behavior of a CoCrMo–Ti6Al4V alloy pair was examined under simulated inflammatory conditions by introducing H₂O₂. A running condition fretting map (RCFM) was established, identifying three fretting regimes: partial slip (PSR), mixed fretting (MFR), and gross slip (GSR). Compared with normal physiological conditions, the presence of H₂O₂ markedly accelerated corrosion and aggravated material degradation across all regimes. The damage mechanisms of the Ti6Al4V–CoCrMo pair vary significantly across different regimes: abrasive wear and tribocorrosion dominate in PSR; adhesive wear and intensified tribocorrosion occur in MFR; and in GSR, severe abrasive wear, tribocorrosion were observed. Increasing H₂O₂ concentration enhanced thermodynamic stability but intensified corrosion kinetics. Concurrently, the dominant damage mechanism transitions from abrasive wear to tribocorrosion characterized by spallation. These collectively lead to a marked increase in material loss and metal ion release. Overall, H₂O₂ promotes cathodic depolarization and the formation of mechanically unstable oxide films, thereby strengthening corrosion-wear synergy and exacerbating material damage under inflammatory conditions.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111793"},"PeriodicalIF":6.1,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.triboint.2026.111798
Feng Wei , Xinyan Wang , Shuwen He , Wan Yan , Xiaozhi Zhan , Tao Zhu , Hai Xu , Rongsheng Cai , Xuzhi Hu , Feng Zhou
Water-based lubricants hold significant importance across multiple fields due to their environmental benignity, non-flammable safety, excellent thermal conductivity, and cost-effectiveness. However, modern water-based lubricants suffer from severe shortcomings in lubrication efficiency and anti-wear performance, limiting their broader applications. To address this problem, additives such as nonionic surfactants can be added into the formulations. This study investigates the adsorption behaviours of a typical group of nonionic surfactants, alkyl ethoxylates, denoted as C12Em, (m = 3, 6, 12, 23) on 304 stainless-steel surfaces and their correlation with lubrication performance. By using surface tension measurements, contact angle measurements, friction and wear tests, as well as various surface characterization techniques (such as spectroscopic ellipsometry, quartz crystal microbalance with dissipation, and neutron reflectometry), the intrinsic connection between the molecular structure of nonionic surfactants and their lubrication performance can be revealed. The results demonstrate that the balance between hydrophilic and hydrophobic segments in the molecular structure directly influences their adsorption configuration on metal surfaces, thereby exerting a significant impact on their lubrication and anti-wear performance. Specifically, nonionic surfactants with shorter ethoxylate chain lengths (EO) (e.g., C12E3) form dense bilayers, providing excellent lubrication and anti-wear effects, whereas those with longer EO chains (e.g., C12E12 and C12E23) exhibit weaker adsorption abilities and inferior lubrication performance. This research not only provides a theoretical basis for the design of high-performance, eco-friendly water-based lubricants but also propels the advancement of environmentally friendly lubricating materials.
{"title":"Unveiling the effects of nanostructure of adsorbed nonionic surfactants on water-based lubrication","authors":"Feng Wei , Xinyan Wang , Shuwen He , Wan Yan , Xiaozhi Zhan , Tao Zhu , Hai Xu , Rongsheng Cai , Xuzhi Hu , Feng Zhou","doi":"10.1016/j.triboint.2026.111798","DOIUrl":"10.1016/j.triboint.2026.111798","url":null,"abstract":"<div><div>Water-based lubricants hold significant importance across multiple fields due to their environmental benignity, non-flammable safety, excellent thermal conductivity, and cost-effectiveness. However, modern water-based lubricants suffer from severe shortcomings in lubrication efficiency and anti-wear performance, limiting their broader applications. To address this problem, additives such as nonionic surfactants can be added into the formulations. This study investigates the adsorption behaviours of a typical group of nonionic surfactants, alkyl ethoxylates, denoted as C<sub>12</sub>E<sub>m</sub>, (m = 3, 6, 12, 23) on 304 stainless-steel surfaces and their correlation with lubrication performance. By using surface tension measurements, contact angle measurements, friction and wear tests, as well as various surface characterization techniques (such as spectroscopic ellipsometry, quartz crystal microbalance with dissipation, and neutron reflectometry), the intrinsic connection between the molecular structure of nonionic surfactants and their lubrication performance can be revealed. The results demonstrate that the balance between hydrophilic and hydrophobic segments in the molecular structure directly influences their adsorption configuration on metal surfaces, thereby exerting a significant impact on their lubrication and anti-wear performance. Specifically, nonionic surfactants with shorter ethoxylate chain lengths (EO) (e.g., C<sub>12</sub>E<sub>3</sub>) form dense bilayers, providing excellent lubrication and anti-wear effects, whereas those with longer EO chains (e.g., C<sub>12</sub>E<sub>12</sub> and C<sub>12</sub>E<sub>23</sub>) exhibit weaker adsorption abilities and inferior lubrication performance. This research not only provides a theoretical basis for the design of high-performance, eco-friendly water-based lubricants but also propels the advancement of environmentally friendly lubricating materials.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111798"},"PeriodicalIF":6.1,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study employed a gradient preheating process (from room temperature to 350°C) to assist laser cladding technology, successfully producing a WTaMoNb refractory high-entropy alloy coating on an Inconel 718 substrate. It systematically investigated the cross-scale regulation mechanism of preheating temperature on the coating's macroscopic formation, microstructure, and high-temperature properties. The study reveals that the preheating process significantly suppresses porosity and crack formation by reducing the cooling-solidification rate of the melt pool, thereby enhancing coating formation quality. Phase analysis confirmed that all coatings comprised body centered cubic (BCC) phase, (Ni, Fe) phase, and Fe7(Nb, Ta)3 intermetallic compound (IMC). While preheating temperatures did not induce new phase formation, they optimized phase distribution and precipitation ratios by regulating element diffusion kinetics. Increasing preheating temperatures enhanced the diffraction peak intensities of both BCC phases and IMCs to varying degrees. Performance tests revealed that the S4 coating (preheated at 250℃) exhibited the highest microhardness (897.2 HV) due to the combined effect of solid solution strengthening and precipitation strengthening, which was 3.6 times higher than that of the substrate. The high-temperature wear rate (2.39 ×10−5 mm3/mN) and oxidation weight gain rate (0.29 mg2·cm−4·h−1) were both optimized to one fifth of the substrate, demonstrating the best high-temperature performance. This study provides a new strategy for the preparation and performance optimization of high-performance refractory high-entropy alloy coatings.
{"title":"Microstructural evolution and high-temperature properties of laser cladding WTaMoNb refractory high-entropy alloy coatings: The critical role of gradient preheating temperature","authors":"Kaitian Mei , Wenshan Guo , Yangyang Fang , Jiayuan Huang , Wangqing Wu （吴旺青）","doi":"10.1016/j.triboint.2026.111792","DOIUrl":"10.1016/j.triboint.2026.111792","url":null,"abstract":"<div><div>This study employed a gradient preheating process (from room temperature to 350°C) to assist laser cladding technology, successfully producing a WTaMoNb refractory high-entropy alloy coating on an Inconel 718 substrate. It systematically investigated the cross-scale regulation mechanism of preheating temperature on the coating's macroscopic formation, microstructure, and high-temperature properties. The study reveals that the preheating process significantly suppresses porosity and crack formation by reducing the cooling-solidification rate of the melt pool, thereby enhancing coating formation quality. Phase analysis confirmed that all coatings comprised body centered cubic (BCC) phase, (Ni, Fe) phase, and Fe<sub>7</sub>(Nb, Ta)<sub>3</sub> intermetallic compound (IMC). While preheating temperatures did not induce new phase formation, they optimized phase distribution and precipitation ratios by regulating element diffusion kinetics. Increasing preheating temperatures enhanced the diffraction peak intensities of both BCC phases and IMCs to varying degrees. Performance tests revealed that the S4 coating (preheated at 250℃) exhibited the highest microhardness (897.2 HV) due to the combined effect of solid solution strengthening and precipitation strengthening, which was 3.6 times higher than that of the substrate. The high-temperature wear rate (2.39 ×10<sup>−5</sup> mm<sup>3</sup>/mN) and oxidation weight gain rate (0.29 mg<sup>2</sup>·cm<sup>−4</sup>·h<sup>−1</sup>) were both optimized to one fifth of the substrate, demonstrating the best high-temperature performance. This study provides a new strategy for the preparation and performance optimization of high-performance refractory high-entropy alloy coatings.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"219 ","pages":"Article 111792"},"PeriodicalIF":6.1,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号