Tribology Letters最新文献

{"title":"In-situ Synthesis of Nickel Nanoparticles in Olive Oil and Study of Their Tribological Properties as Vegetable Oil Additives","authors":"Wenya Xu,&nbsp;Guangbin Yang,&nbsp;Shengmao Zhang,&nbsp;Yujuan Zhang,&nbsp;Shuguang Fan,&nbsp;Laigui Yu,&nbsp;Pingyu Zhang","doi":"10.1007/s11249-024-01945-2","DOIUrl":"10.1007/s11249-024-01945-2","url":null,"abstract":"<div><p>Vegetable oil-based lubricants have a tendency to replace traditional petroleum-based lubricants due to their biodegradability, high flash point, low volatility, and low cost. However, polar molecules such as fatty acids in vegetable oil compete for adsorption with nanoparticles during rubbing process, resulting in imperfect tribological performance of nanoparticles. Magnetic nanoadditives can be adsorbed on the contact surface of iron-based friction materials through magnetic effects, which provides a new idea for solving competitive adsorption problems between additives and base oil. In this study, Ni nanoparticles with a particle size of approximately 15.6 nm were synthesized in-situ in olive oil using nickel acetylacetone as the nickel source and olive oil as the modifier and solvent required for the reaction, which is a simple, efficient, and environmentally friendly in-situ synthesis method. The as-synthesized Ni nanoparticles can significantly improve the antiwear capabilities of olive oil, reducing the wear scar diameter by 30%. The morphology and elemental analysis of wear scar indicated that a composite tribofilm including nickel, nickel oxide, iron oxide, carbon film, and polar fatty acid molecules in olive oil is formed on the rubbing surface, greatly improving the antiwear performance, which opens up an opportunity for the further application of new green nanolubricants.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694835","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 Effect of Synovial Fluid Constituents on Boundary Lubrication of Superficial Area of Articular Cartilage","authors":"Wenxiao Li,&nbsp;Takehiro Morita,&nbsp;Yoshinori Sawae","doi":"10.1007/s11249-024-01944-3","DOIUrl":"10.1007/s11249-024-01944-3","url":null,"abstract":"<div><p>In this study, the complementary lubricating function of the superficial area of the articular cartilage and synovial fluid (SF) constituents was examined. The cartilage specimens underwent two different degenerative treatments: gentle washing with detergent to remove lipids and proteins absorbed onto the cartilage surface and incubation in a NaCl solution to remove lubricin from the surface. Sliding experiments with a glass probe and cartilage specimens were conducted at various speeds and low contact loads using lubricants containing SF constituents, such as phospholipids, proteins, and hyaluronic acid (HA). The treated cartilage surface and protein adsorption were observed using a fluorescence microscope and water immersion objectives to explore the underlying mechanisms of the difference in friction. The results showed that fresh SF exhibited low friction even after degenerative treatment. HA and phospholipids had no boundary lubrication effect, whereas the lubricant containing albumin and γ-globulin maintained a consistently low coefficient of friction, even after degenerative treatment. The significance of the interaction between albumin and γ-globulin should be emphasized.</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 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714178","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 Viscoelastic Contacts: The Role of Adhesion, Boundary Conditions, and Finite Geometry","authors":"Luciano Afferrante,&nbsp;Guido Violano,&nbsp;Giuseppe P. Demelio","doi":"10.1007/s11249-024-01940-7","DOIUrl":"10.1007/s11249-024-01940-7","url":null,"abstract":"<div><p>In this study, we investigate the tangential sliding of a rigid Hertzian indenter on a viscoelastic substrate, a problem of practical interest due to the crucial role that sliding contacts play in various applications involving soft materials. A finite element model is developed, where the substrate is modelled using a standard linear viscoelastic model with one relaxation time, and adhesion is incorporated using a Lennard–Jones potential law. We propose an innovative approach to model tangential sliding without imposing any lateral displacement, thereby enhancing the numerical efficiency. Our goal is to investigate the roles of adhesive regimes, boundary conditions (displacement and force-controlled conditions), and finite thickness of the substrate. Results indicate significant differences in the system’s behaviour depending on the boundary conditions and adhesion regime. In the short-range adhesion regime, the contact length <span>(mathcal {L})</span> initially increases with sliding speed before decreasing, showing a maximum at intermediate speeds. This behaviour is consistent with experimental observations in rubber-like materials and is a result of the transition from small-scale to large-scale viscous dissipation regimes. For long-range adhesion, this behaviour disappears and <span>(mathcal {L})</span> decreases monotonically with sliding speed. The viscoelastic friction coefficient <span>(mu)</span> exhibits a bell-shaped curve with its maximum value influenced by the applied load, both in long-range and short-range adhesion. However, under displacement control, <span>(mu)</span> can be unbounded near a specific sliding speed, correlating with the normal force crossing zero. Finally, a transition towards a long-range adhesive behaviour is observed when reducing the thickness <i>t</i> of the viscoelastic layer, which is assumed to be bonded to a rigid foundation. Moreover, the friction coefficient reduces when <i>t</i> tends to zero. These findings provide insights into the viscoelastic and adhesive interactions during sliding, highlighting the critical influence of boundary conditions on contact mechanics.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694759","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":"Obtaining Ultra-long Wear Lifetime of Graphene Oxide Films Under High Contact Stress Through Soft and Hard Interbeded Formation Mode","authors":"Li Chen,&nbsp;Hang Zhu,&nbsp;Gang Wu,&nbsp;Bo Mu,&nbsp;Yaqian Liu,&nbsp;Xingkai Zhang,&nbsp;Changning Bai","doi":"10.1007/s11249-024-01942-5","DOIUrl":"10.1007/s11249-024-01942-5","url":null,"abstract":"<div><p>As the quintessential representation of graphene derivatives, graphene oxide (GO) has demonstrated unparalleled potential in micro/nano electronic mechanical systems, which visibly enhances the efficiency and accuracy of moving mechanical devices. However, GO has always been subject to the problem of insufficient wear lifetime, and the subsequent improvement is still a challenge, especially under high contact stress. In this paper, making use of the strong charge interactions between positively charged poly(acrylamide-co-diallyldimethylammonium chloride) (Brand: PQ-7) and negatively charged GO, both were alternately spin-coated on the silicon substrates modified by 3-aminopropyltriethoxysilane as an adhesive layer to form (GO/PQ-7)_n composite multilayer film. The service life of (GO/PQ-7)₅ multilayer film exceeds 27000 s under high load of 4N, which is 20 times longer than that of the GO film. The superior friction performance is ascribed to the distinctive structure of (GO/PQ-7)_n composite multilayers, that is, an elastic 3-dimensional stack composed of rigid GO and flexible polymer. This soft and hard interbeded formation film not only integrates the interface well, but also effectively prevents the crack expansion. It also leverages the advantages of soft layers providing stress relief and hard layers providing load-bearing capacity. What's more, friction-induced conversion of partial GO to graphene ensures low friction at the sliding interface. This strategy provides an open platform for the design and fabrication of lubricating films for micro/nano electronic mechanical systems and other microdevices.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679804","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":"Superlubricity of Sputtered MoS2 Film in Dry Air Enabled by Proton Irradiation","authors":"Xinhu Wu,&nbsp;Yongfu Wang,&nbsp;Kuiliang Gong,&nbsp;Gaiqing Zhao,&nbsp;Xudong Sui,&nbsp;Xiaobo Wang","doi":"10.1007/s11249-024-01938-1","DOIUrl":"10.1007/s11249-024-01938-1","url":null,"abstract":"<div><p>The superlubricity of sputtered MoS₂ film under dry air environment was achieved by low-energy proton irradiation of 25 keV for the first time. We found that proton (H⁺) irradiation is able to break the Mo-S covalent bonding of as-deposited MoS₂ film and leads to the formation of MoS₂ nanocrystalline domains. The dangling bonds at edge planes or newly exposed edges could be passivated with hydrogen ions by bonding interaction under proton irradiation, forming hydric MoS₂ nanocrystalline domains with stable S–H bind, resulting in superior antioxidant capacity of proton-irradiated MoS₂ film compared to its non-irradiated counterpart. Importantly, proton irradiation can penetrate the interior of sputtered MoS₂ film with thickness over 1 µm and restructure the as-deposited MoS₂ film into nanocrystalline MoS₂ domains to achieve superlubricity and life extension under dry air conditions.</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 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664485","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":"Temperature Rise in Frictional Sliding Contact of Elastic–Plastic Solids with Fractal Surface","authors":"Si-Cheng Wang,&nbsp;Yue Ding,&nbsp;Yunlai Zhou,&nbsp;Gang-Feng Wang","doi":"10.1007/s11249-024-01934-5","DOIUrl":"10.1007/s11249-024-01934-5","url":null,"abstract":"<div><p>Surface temperature rise during the sliding process significantly affects friction and wear, which is crucial for the performance of mechanical systems. In this work, the finite element method is adopted to simulate the frictional contact between a two-dimensional cylinder and an elastic–plastic substrate with a self-affine fractal surface. The influences of surface profile and external load on the maximum temperature rise are examined. Either the increase of roughness or the decrease of Hurst index would result in a reduction in contact area, and are more likely to produce higher maximum temperature and surface damage. Additionally, higher sliding velocity increases the maximum temperature, but the uplift of external load tends to eliminate the effects of rough profile on temperature and contact pressure. A general relation between maximum surface temperature rise and contact area for rough surfaces is proposed to predict the occurrence of the high-temperature hotspots during the sliding process. This study provides insights and novel perspectives for the understanding of the frictional and thermodynamic behavior of contact in mechanical structures.</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 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664478","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":"Counterion-Driven Mechanochemical Reactions at TC4 Alloy/SiO2 Interfaces: Electrical Double Layer and Dynamic Ionic Radius","authors":"Jinwei Liu,&nbsp;Xin Zeng,&nbsp;Peng Zhang,&nbsp;Xiang Peng,&nbsp;Deping Yu","doi":"10.1007/s11249-024-01939-0","DOIUrl":"10.1007/s11249-024-01939-0","url":null,"abstract":"<div><p>Ti-6Al-4V (TC4) alloy with ultra-smooth surfaces has found extensive application in biomedical fields. Chemical mechanical polishing is a crucial method for achieving ultra-smooth surfaces, but its efficiency in polishing TC4 alloy surfaces is low. This study proposes a new approach to enhance the polishing efficiency by tuning counterions, which significantly influence both chemical corrosion and microscopic interaction forces. The mechanism involves Li⁺/Na⁺/K⁺ regulating the action intensity at the tribological interface by altering the thickness of the electrical double layer and dynamic ionic radius. On the one hand, reducing the thickness of the electrical double layer from 1.41 to 0.46 nm can enhance the intensity of chemical reactions, and the smaller the dynamic ionic radius of the counterion, the more pronounced the chemical corrosion caused by H₂O₂ becomes. Combining the two, the reaction products of H₂O₂ (HO₂⁻ and OOH⁻) can more readily react with Ti to form fragile reaction products with the help of K⁺. On the other hand, as the electrostatic repulsion force weakens, the SiO₂ particles exert a stronger mechanical force, allowing for quicker removal of the fragile reaction products. Thus, in the presence of 10 wt%H₂O₂ and 200 mM K₂SO₄, a polishing efficiency of 1197 nm/min is achieved, with the <i>S</i>_a of 2.7 nm over a scanning area of 195.8 × 195.8 μm², and without polishing damage layer on the substrate. The findings provide mechanistic insight for further exploring the limits of polishing performance in CMP of titanium alloys.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"73 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636979","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":"Machine-Learning-Assisted Identification and Formulation of High-Pressure Lubricant-Piezoviscous-Response Parameters for Minimum Film Thickness Determination in Elastohydrodynamic Circular Contacts","authors":"W. Habchi,&nbsp;S. Bair","doi":"10.1007/s11249-024-01937-2","DOIUrl":"10.1007/s11249-024-01937-2","url":null,"abstract":"<div><p>From the earliest theoretical studies on elastohydrodynamic lubrication, it was believed that film build-up is governed by lubricant rheology in the low-pressure contact inlet. Recently, it was discovered that this is only true for the theoretical line contact case, where lubricant out-of-contact lateral flow is absent. In actual contacts, though central film thickness is indeed governed by low-pressure lubricant rheology, minimum film thickness is additionally influenced by the high-pressure response. Thus, a proper prediction of minimum film thickness (either by analytical formulae, or machine-learning frameworks) would require input parameters that define the high-pressure viscous response of the lubricant. The current work identifies and formulates these parameters with the help of machine-learning regression tools. These are fed with minimum film thickness results from finite element simulations of smooth steady-state isothermal Newtonian circular contacts, lubricated with sets of hypothetical fluids having the same pressure-viscosity response at low pressure, but different high-pressure ones. It is found that conventional dimensionless groups are not sufficient to describe minimum film thickness formation, and that an additional pressure-viscosity coefficient—evaluated at half the Hertzian contact pressure—is required.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"72 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636640","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":"Mechanical Durability Testing and Self-Recovery of Topographically Modified Superhydrophobic Surfaces","authors":"Kirill Misiiuk,&nbsp;Arthur Braud,&nbsp;Richard Blaikie,&nbsp;Andrew Sommers,&nbsp;Sam Lowrey","doi":"10.1007/s11249-024-01936-3","DOIUrl":"10.1007/s11249-024-01936-3","url":null,"abstract":"<div><p>The abrasion testing process of topographically modified surfaces is investigated and their mechanical durability and wear characteristics are presented. The primary aim of the study is to demonstrate that a simple abrasion testing process carries a number of subtle complexities which are crucial for getting comparable results—i.e., sample area, abrasion duration, and presence of a microstructure. All of these factors can significantly alter the results of the testing process and have to be considered during comparison with other durability results. This study also demonstrates how topographically modified aluminum structures tend to restore their hydrophobicity after noticeable mechanical damage due to the natural oxidation process, whereas control samples stay in a hydrophilic state. The findings could be applied to improving the performance of wind or steam turbine blades.</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":"72 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600645","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-monotonic Evolution of Contact Area in Soft Contacts During Incipient Torsional Loading","authors":"Bo Zhang,&nbsp;Mariana de Souza,&nbsp;Daniel M. Mulvihill,&nbsp;Davy Dalmas,&nbsp;Julien Scheibert,&nbsp;Yang Xu","doi":"10.1007/s11249-024-01930-9","DOIUrl":"10.1007/s11249-024-01930-9","url":null,"abstract":"<div><p>Many properties of soft contact interfaces are controlled by the contact area (e.g. friction, contact stiffness and surface charge generation). The contact area increases with the contact age at rest. In contrast, it usually reduces under unidirectional shear loading. Although the physical origin of such a reduction is still debated, it always happens in an anisotropic way because the reduction mainly occurs along the shearing direction. Whether such anisotropy is a necessary condition for shear-induced area reduction remains an open question. Here, we investigate the contact area evolution of elastomer-based sphere-plane contacts under an isotropic shear loading, i.e. torsional loading. We find that, when macroscopic sliding is reached, the contact area has undergone a net area reduction. However, the area evolves non-monotonically as the twisting angle increases, with an initial rise up to a maximum before dropping to the value during macroscopic sliding. The ratio of maximum to initial contact area is found weakly dependent on the normal load, angular velocity and dwell time (time interval between the instants when the normal load and twist motion are first applied) within the investigated ranges. We show that non-monotonic area evolution can also be found under unidirectional shear loading conditions under large normal force. These observations challenge the current descriptions of shear-induced contact area evolution and are expected to serve as a benchmark for future modelling attempts in the field.</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":"72 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595995","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}