Pub Date : 2025-02-09DOI: 10.1016/j.triboint.2025.110594
Rui Yu , Haichao Liu , Qingmiao Sun , Wenjing Lou , Shengmao Zhang , Xiaobo Wang , Yan Zhao
The tribofilm formation mechanisms of Zinc dialkyldithiophosphate (ZDDP) anti-wear additives have been extensively studied in oil lubrication. However, they are rarely reported in grease lubrication. In this study, the Mini Traction Machine (MTM) equipped with the Spacer Layer Interferometry iMaging (SLIM) technique is used to monitor the formation of ZDDP tribofilms in situ in Lithium-based grease- and its corresponding base oil- and bled oil- lubricated rolling/sliding contacts at low speeds. The results indicate that, compared to oil lubrication, the thickener deposited films hinder the formation of ZDDP tribofilms through reducing the interfacial friction in grease lubrication under moderate lubrication conditions. Among various operating conditions and ZDDP concentrations, the slide-to-roll ratio (SRR) dominates the formation of the ZDDP tribofilms by removing the grease thickener deposited films. By further extending to severe operating conditions in terms of load, temperature, SRR, and ZDDP concentration, the growing process of tribofilms have been analyzed for low-speed grease lubrication.
{"title":"Experimental study on ZDDP tribofilm formation in grease lubricated rolling/sliding contacts","authors":"Rui Yu , Haichao Liu , Qingmiao Sun , Wenjing Lou , Shengmao Zhang , Xiaobo Wang , Yan Zhao","doi":"10.1016/j.triboint.2025.110594","DOIUrl":"10.1016/j.triboint.2025.110594","url":null,"abstract":"<div><div>The tribofilm formation mechanisms of Zinc dialkyldithiophosphate (ZDDP) anti-wear additives have been extensively studied in oil lubrication. However, they are rarely reported in grease lubrication. In this study, the Mini Traction Machine (MTM) equipped with the Spacer Layer Interferometry iMaging (SLIM) technique is used to monitor the formation of ZDDP tribofilms in situ in Lithium-based grease- and its corresponding base oil- and bled oil- lubricated rolling/sliding contacts at low speeds. The results indicate that, compared to oil lubrication, the thickener deposited films hinder the formation of ZDDP tribofilms through reducing the interfacial friction in grease lubrication under moderate lubrication conditions. Among various operating conditions and ZDDP concentrations, the slide-to-roll ratio (SRR) dominates the formation of the ZDDP tribofilms by removing the grease thickener deposited films. By further extending to severe operating conditions in terms of load, temperature, SRR, and ZDDP concentration, the growing process of tribofilms have been analyzed for low-speed grease lubrication.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110594"},"PeriodicalIF":6.1,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387576","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}
To reveal the mechanism why low friction state of SiC/water system is maintained through the repeated formation and removal processes of tribolayer, we performed molecular dynamics sliding simulations. Our results revealed that tribochemical reactions of amorphous SiC (a-SiC) with water form tribolayer consisting of silica-based layer and carbon layer, and constant supply of silica-based layer by continuous tribochemical reactions is required to maintain hydrodynamic lubrication, whereas the carbon layer prevents adhesion. However, if carbon layer covers the entire interface, it would prevent hydrodynamic lubrication. We proposed here that uneven distribution of chemical bonds in the a-SiC substrate is important for maintaining hydrodynamic lubrication and low friction, because such distribution continuously forms the silica-based layer and carbon layer at the same time.
{"title":"Continuous formation and removal mechanism of tribolayer on silicon carbide under water lubricated conditions: A ReaxFF reactive molecular dynamics study","authors":"Masayuki Kawaura , Yusuke Ootani , Shogo Fukushima , Yixin Su , Nobuki Ozawa , Koshi Adachi , Momoji Kubo","doi":"10.1016/j.triboint.2025.110579","DOIUrl":"10.1016/j.triboint.2025.110579","url":null,"abstract":"<div><div>To reveal the mechanism why low friction state of SiC/water system is maintained through the repeated formation and removal processes of tribolayer, we performed molecular dynamics sliding simulations. Our results revealed that tribochemical reactions of amorphous SiC (a-SiC) with water form tribolayer consisting of silica-based layer and carbon layer, and constant supply of silica-based layer by continuous tribochemical reactions is required to maintain hydrodynamic lubrication, whereas the carbon layer prevents adhesion. However, if carbon layer covers the entire interface, it would prevent hydrodynamic lubrication. We proposed here that uneven distribution of chemical bonds in the a-SiC substrate is important for maintaining hydrodynamic lubrication and low friction, because such distribution continuously forms the silica-based layer and carbon layer at the same time.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110579"},"PeriodicalIF":6.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.triboint.2025.110590
G.N. Rossopoulos , I. Pervelis , D. Skaltsas , C.I. Papadopoulos , O. Vlachos , G. Koutsoumpas , C. Leontopoulos
The present study focuses on the experimental characterization of different stern-tube bearing materials regarding their tribological and acoustic performance. Three materials, in particular, COMPAC elastomeric polymer, rubber polymer, and white metal (Babbitt), were evaluated under water and oil-lubricated conditions using a flat-on-disk setup. Surface topography analysis, stiffness coefficient measurement, and performance assessment were conducted in three phases. Performance assessment under water/oil-lubricated conditions was conducted measuring vertical force, friction force, and friction coefficient, along with the synchronous recording of sound pressure emissions using a microphone. Results showed significant differences in friction characteristics and acoustic performance of the specimens under varying loads and rotational speeds. COMPAC specimens with a shape factor of 1.0 exhibited lower friction coefficient, in comparison to Babbitt liners, while entering the hydrodynamic regime, for linear velocities exceeding 0.7 m/s. At 50 RPM and 0.2 MPa load, all specimens exhibited comparable acoustic performance in the low frequency range (16–500 Hz). COMPAC and SAE-30-lubricated Babbitt specimens maintained noise levels below 60 dB at frequencies above 1500 Hz, highlighting their suitability for noise-sensitive applications. Rubber and SAE-10-lubricated Babbitt liners exhibited increased noise levels at frequencies above 3000 Hz. Rubber specimens were characterized by higher friction coefficient and sound pressure levels across all conditions, especially at frequencies above 1000 Hz. Sound pressure levels increased with rotational speed for all specimen types, with the differences between them being less pronounced at higher speeds.
{"title":"Experimental characterization of the tribological and acoustic performance of different stern-tube bearing materials","authors":"G.N. Rossopoulos , I. Pervelis , D. Skaltsas , C.I. Papadopoulos , O. Vlachos , G. Koutsoumpas , C. Leontopoulos","doi":"10.1016/j.triboint.2025.110590","DOIUrl":"10.1016/j.triboint.2025.110590","url":null,"abstract":"<div><div>The present study focuses on the experimental characterization of different stern-tube bearing materials regarding their tribological and acoustic performance. Three materials, in particular, COMPAC elastomeric polymer, rubber polymer, and white metal (Babbitt), were evaluated under water and oil-lubricated conditions using a flat-on-disk setup. Surface topography analysis, stiffness coefficient measurement, and performance assessment were conducted in three phases. Performance assessment under water/oil-lubricated conditions was conducted measuring vertical force, friction force, and friction coefficient, along with the synchronous recording of sound pressure emissions using a microphone. Results showed significant differences in friction characteristics and acoustic performance of the specimens under varying loads and rotational speeds. COMPAC specimens with a shape factor of 1.0 exhibited lower friction coefficient, in comparison to Babbitt liners, while entering the hydrodynamic regime, for linear velocities exceeding 0.7 m/s. At 50 RPM and 0.2 MPa load, all specimens exhibited comparable acoustic performance in the low frequency range (16–500 Hz). COMPAC and SAE-30-lubricated Babbitt specimens maintained noise levels below 60 dB at frequencies above 1500 Hz, highlighting their suitability for noise-sensitive applications. Rubber and SAE-10-lubricated Babbitt liners exhibited increased noise levels at frequencies above 3000 Hz. Rubber specimens were characterized by higher friction coefficient and sound pressure levels across all conditions, especially at frequencies above 1000 Hz. Sound pressure levels increased with rotational speed for all specimen types, with the differences between them being less pronounced at higher speeds.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110590"},"PeriodicalIF":6.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422091","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 : 2025-02-07DOI: 10.1016/j.triboint.2025.110532
Zohaib Arshad , Emad Ghandourah , Muhammad Asif Zahoor Raja , Zahoor Shah , Amjad Ali Pasha , Syed Khadam Hussain , Waqar Azeem Khan , Md. Mottahir Alam
Scientists are studying the thermal characteristics and energy requirements of blood containing magnetic nanoparticles using the Darcy-Forchheimer flow model (DFFM) framework. This research examines various heat transfer mechanisms, including thermal radiation and viscous effects, to advance medical treatments by understanding how these particles behave in arterial blood flow under magnetic fields. The study employs a tetra hybrid nano-fluid consisting of silver (), gold () and titanium-oxide , copper , and blood is treated as the base fluid. Gold, copper, and silver nano-particles are taken for their potential in imaging and drug delivery. The objective of this study is to evaluate the performance of tetra hybrid nano-fluid models (THNFM) using numerical approach along with AI integrated analysis. Using artificial intelligence techniques that incorporate predicting methods yields accurate predictions for this complex fluid system. The model accounts for both random variables and turbulent flow characteristics. Mathematical simplification is achieved by converting the governing partial differential equations to ordinary differential equations through similarity methods. ND-Solver Mathematica technique is employed to solve converted ODEs to gain behavior of different parameters. After getting tabular data MATLAB tool is used to process it for Neural Fitting mechanism. The dataset is split into 70 %, 15 %, and 15 % for training, testing, and validation in the Neural Network-Back propagation Levenberg-Marquardt scheme (NN-BPLMS). NN-BPLMS is applied to draw graphs of performance, state function, error histogram, regression analysis and function fit numerically using the sequence of train, validate and test (TTV) in NN-BPLMS processes. Applied technique exhibited the approximate solutions of TETHMNF DFFM for different cases and comparison with reference results to verify the correctness of the proposed NN-BPLMS. This applied Neural Network techniques effectively solved the TETHMNF performance with squared mean error (MSE), reflections of regression analysis (RA) and histogram studies (EHA). The comparison between the results obtained prior and after implication of the AI-NNs, the errors ranging from to are observed, which confirms the accuracy of the method.
{"title":"Artificial intelligence-based procedure to analyze heat transfer features for chemically reactive Darcy-Forchheimer flow of magnetized tetra-hybrid nanofluid flow capturing Joule heating aspects through stenotic artery","authors":"Zohaib Arshad , Emad Ghandourah , Muhammad Asif Zahoor Raja , Zahoor Shah , Amjad Ali Pasha , Syed Khadam Hussain , Waqar Azeem Khan , Md. Mottahir Alam","doi":"10.1016/j.triboint.2025.110532","DOIUrl":"10.1016/j.triboint.2025.110532","url":null,"abstract":"<div><div>Scientists are studying the thermal characteristics and energy requirements of blood containing magnetic nanoparticles using the Darcy-Forchheimer flow model (DFFM) framework. This research examines various heat transfer mechanisms, including thermal radiation and viscous effects, to advance medical treatments by understanding how these particles behave in arterial blood flow under magnetic fields. The study employs a tetra hybrid nano-fluid consisting of silver (<span><math><mrow><mi>A</mi><mi>g</mi></mrow></math></span>), gold (<span><math><mi>Au</mi></math></span>) and titanium-oxide <span><math><mrow><mo>(</mo><mi>T</mi><mi>i</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></mrow></math></span>, copper <span><math><mrow><mo>(</mo><mi>C</mi><mi>u</mi><mo>)</mo></mrow></math></span>, and blood is treated as the base fluid. Gold, copper, and silver nano-particles are taken for their potential in imaging and drug delivery. The objective of this study is to evaluate the performance of tetra hybrid nano-fluid models (THNFM) using numerical approach along with AI integrated analysis. Using artificial intelligence techniques that incorporate predicting methods yields accurate predictions for this complex fluid system. The model accounts for both random variables and turbulent flow characteristics. Mathematical simplification is achieved by converting the governing partial differential equations to ordinary differential equations through similarity methods. ND-Solver Mathematica technique is employed to solve converted ODEs to gain behavior of different parameters. After getting tabular data MATLAB tool is used to process it for Neural Fitting mechanism. The dataset is split into 70 %, 15 %, and 15 % for training, testing, and validation in the Neural Network-Back propagation Levenberg-Marquardt scheme (NN-BPLMS). NN-BPLMS is applied to draw graphs of performance, state function, error histogram, regression analysis and function fit numerically using the sequence of train, validate and test (TTV) in NN-BPLMS processes. Applied technique exhibited the approximate solutions of TETHMNF DFFM for different cases and comparison with reference results to verify the correctness of the proposed NN-BPLMS. This applied Neural Network techniques effectively solved the TETHMNF performance with squared mean error (MSE), reflections of regression analysis (RA) and histogram studies (EHA). The comparison between the results obtained prior and after implication of the AI-NNs, the errors ranging from <span><math><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>7</mn></mrow></msup></math></span> to<span><math><msup><mrow><mspace></mspace><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></math></span> are observed, which confirms the accuracy of the method.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110532"},"PeriodicalIF":6.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387577","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 : 2025-02-05DOI: 10.1016/j.triboint.2025.110560
Daniel Fochler , Stefan Schwarz , Lukas Kohlmann , Malte Krack
A new instrument has been designed for measuring frictional hysteresis cycles and normal load-indentation curves. The primary purpose of the BMT is the validation of more predictive modeling approaches for damping in friction joints. An important original feature of the BMT is its ability to measure both normal and tangential contact behavior without having to separate the samples. Special attention was paid to alignment and smooth motion in order to permit testing nominally flat-on-flat contacts in the microslip regime. Examples are shown for finely resolved, undistorted hysteresis cycles with relative tangential displacement amplitudes in the sub-micrometer range at about 50 MPa nominal normal pressure, which is maintained well over the tangential load cycle.
{"title":"The Black Metal Tribometer: High-resolution measurement of normal load-indentation curves and partial slip hysteresis cycles","authors":"Daniel Fochler , Stefan Schwarz , Lukas Kohlmann , Malte Krack","doi":"10.1016/j.triboint.2025.110560","DOIUrl":"10.1016/j.triboint.2025.110560","url":null,"abstract":"<div><div>A new instrument has been designed for measuring frictional hysteresis cycles and normal load-indentation curves. The primary purpose of the BMT is the validation of more predictive modeling approaches for damping in friction joints. An important original feature of the BMT is its ability to measure both normal and tangential contact behavior without having to separate the samples. Special attention was paid to alignment and smooth motion in order to permit testing nominally flat-on-flat contacts in the microslip regime. Examples are shown for finely resolved, undistorted hysteresis cycles with relative tangential displacement amplitudes in the sub-micrometer range at about 50 MPa nominal normal pressure, which is maintained well over the tangential load cycle.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110560"},"PeriodicalIF":6.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-05DOI: 10.1016/j.triboint.2025.110578
Shi-Wen Chen, Gang-Feng Wang
The contact of rough spheres is critical in many fields, yet analyzing the effects of roughness and plasticity on the load-area relation is challenging. This paper presents a model for rough elastic-plastic spheres in contact with a rigid plane. Using finite element simulations, we derive an explicit expression for contact pressure in smooth elastic-plastic spheres. For rough spheres, the local load is estimated from this expression, and the local real contact area is determined by the contact behavior of nominally flat elastic-plastic solids, which is established for whole-range using finite element method. By integrating across the contact region, the total real contact area is calculated. The model aligns well with finite element and experimental results, confirming its accuracy and applicability.
{"title":"A contact model for elastic-plastic rough spheres","authors":"Shi-Wen Chen, Gang-Feng Wang","doi":"10.1016/j.triboint.2025.110578","DOIUrl":"10.1016/j.triboint.2025.110578","url":null,"abstract":"<div><div>The contact of rough spheres is critical in many fields, yet analyzing the effects of roughness and plasticity on the load-area relation is challenging. This paper presents a model for rough elastic-plastic spheres in contact with a rigid plane. Using finite element simulations, we derive an explicit expression for contact pressure in smooth elastic-plastic spheres. For rough spheres, the local load is estimated from this expression, and the local real contact area is determined by the contact behavior of nominally flat elastic-plastic solids, which is established for whole-range using finite element method. By integrating across the contact region, the total real contact area is calculated. The model aligns well with finite element and experimental results, confirming its accuracy and applicability.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110578"},"PeriodicalIF":6.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348752","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 : 2025-02-03DOI: 10.1016/j.triboint.2025.110577
Xibo Shao , Yi Ren , Kun Guo , Chengfeng Du , Xianzong Wang , Jiao Chen , Jianxi Liu , Long Wang , Jun Yang
Molybdenum disulfide (MoS2) is an excellent lubricant used in aerospace. Its ability to lubricate and resist wear at temperatures above 400 °C remains a significant challenge, due to its high temperature oxidation. Herein, we demonstrate that excellent high-temperature lubrication can be achieved with coefficient of friction (COF) of 0.21–0.26 at 450–800 ℃ by compounding bismuth oxide (Bi2O3) nanoparticles with MoS2. The improvement of tribological properties above 450 ℃ was due to the synergistic lubrication of MoS2 and Bi2O3. When the temperature was higher than 600 ℃, the tribo-chemical reaction driven by continuous stress and temperature, induced the formation of new ternary oxides (Bi2MoO6 and Bi2Mo3O12) with low shearing nano-grain structure, and a continuous dense lubricating glaze layer composed of Bi2O3, MoO3, Bi2MoO6 and Bi2Mo3O12 was formed at the friction interface. In Bi2MoO6 layered structure, the distortion of MoO6 octahedral structure led to the increase of interlayer distance, which weakened the coupling effect between ions, thus contributing to low shear strength and good lubricity. Our research indicates that the formation of low shear strength Bi2MoO6 ternary oxide is helpful to the realization of high temperature lubrication, which provides a strategy to expand the high temperature lubrication range of MoS2-based solid lubricant.
{"title":"Achieving high temperature lubrication of MoS2-Bi2O3 nanoparticles composite: Through the formation of nanocrystalline ternary oxide and glaze layer","authors":"Xibo Shao , Yi Ren , Kun Guo , Chengfeng Du , Xianzong Wang , Jiao Chen , Jianxi Liu , Long Wang , Jun Yang","doi":"10.1016/j.triboint.2025.110577","DOIUrl":"10.1016/j.triboint.2025.110577","url":null,"abstract":"<div><div>Molybdenum disulfide (MoS<sub>2</sub>) is an excellent lubricant used in aerospace. Its ability to lubricate and resist wear at temperatures above 400 °C remains a significant challenge, due to its high temperature oxidation. Herein, we demonstrate that excellent high-temperature lubrication can be achieved with coefficient of friction (COF) of 0.21–0.26 at 450–800 ℃ by compounding bismuth oxide (Bi<sub>2</sub>O<sub>3</sub>) nanoparticles with MoS<sub>2</sub>. The improvement of tribological properties above 450 ℃ was due to the synergistic lubrication of MoS<sub>2</sub> and Bi<sub>2</sub>O<sub>3</sub>. When the temperature was higher than 600 ℃, the tribo-chemical reaction driven by continuous stress and temperature, induced the formation of new ternary oxides (Bi<sub>2</sub>MoO<sub>6</sub> and Bi<sub>2</sub>Mo<sub>3</sub>O<sub>12</sub>) with low shearing nano-grain structure, and a continuous dense lubricating glaze layer composed of Bi<sub>2</sub>O<sub>3</sub>, MoO<sub>3</sub>, Bi<sub>2</sub>MoO<sub>6</sub> and Bi<sub>2</sub>Mo<sub>3</sub>O<sub>12</sub> was formed at the friction interface. In Bi<sub>2</sub>MoO<sub>6</sub> layered structure, the distortion of MoO<sub>6</sub> octahedral structure led to the increase of interlayer distance, which weakened the coupling effect between ions, thus contributing to low shear strength and good lubricity. Our research indicates that the formation of low shear strength Bi<sub>2</sub>MoO<sub>6</sub> ternary oxide is helpful to the realization of high temperature lubrication, which provides a strategy to expand the high temperature lubrication range of MoS<sub>2</sub>-based solid lubricant.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110577"},"PeriodicalIF":6.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143330526","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 : 2025-02-03DOI: 10.1016/j.triboint.2025.110563
Jan Ulrich Michaelis , Sandra Kiese , Stefan Hofmann , Thomas Lohner , Peter Eisner
Continuous growth in lubricant volume worldwide, environmental hazard of fossil-based lubricants and anthropogenic climate change are reflected in an increasing demand for green, sustainable lubrication. In the presented work, the influence of molecular mass of hydroxyethyl celluloses on rheology, elastohydrodynamic friction and film thickness of aqueous lubricants was investigated experimentally. Polyalphaolefin and polyethylene glycol were used as reference lubricants. All lubricants were formulated to have the same dynamic zero-shear viscosity. The average molar mass of commercial hydroxyethyl cellulose was adjusted by enzymatic hydrolysis. 40 to 70 wt% glycerol were added to improve the film formation capability and high-shear viscosity. The results indicate that commercial hydroxyethyl celluloses with weight average molar masses above 88 kg mol-1 are not suitable to increase elastohydrodynamic film thickness due to shear-thinning even at moderate shear rates. Hydrolysis increased the critical shear stress by an order of magnitude to 1.13 × 104 Pa. Compared to the reference lubricants, elastohydrodynamic friction was reduced by more than 90 %. Nevertheless, due to the pronounced shear-thinning behavior, a weight average molar mass of 19 kg mol-1 seems to represent a threshold for relevant lubricant film formation in elastohydrodynamically lubricated contacts. Overall, the results show that the combination of hydroxyethyl cellulose and glycerol is well suited for viscosity modification of aqueous lubricants.
{"title":"Elastohydrodynamic lubrication of aqueous hydroxyethyl cellulose-glycerol lubricants","authors":"Jan Ulrich Michaelis , Sandra Kiese , Stefan Hofmann , Thomas Lohner , Peter Eisner","doi":"10.1016/j.triboint.2025.110563","DOIUrl":"10.1016/j.triboint.2025.110563","url":null,"abstract":"<div><div>Continuous growth in lubricant volume worldwide, environmental hazard of fossil-based lubricants and anthropogenic climate change are reflected in an increasing demand for green, sustainable lubrication. In the presented work, the influence of molecular mass of hydroxyethyl celluloses on rheology, elastohydrodynamic friction and film thickness of aqueous lubricants was investigated experimentally. Polyalphaolefin and polyethylene glycol were used as reference lubricants. All lubricants were formulated to have the same dynamic zero-shear viscosity. The average molar mass of commercial hydroxyethyl cellulose was adjusted by enzymatic hydrolysis. 40 to 70<!--> <!-->wt% glycerol were added to improve the film formation capability and high-shear viscosity. The results indicate that commercial hydroxyethyl celluloses with weight average molar masses above 88<!--> <!-->kg<!--> <!-->mol<sup>-1</sup> are not suitable to increase elastohydrodynamic film thickness due to shear-thinning even at moderate shear rates. Hydrolysis increased the critical shear stress by an order of magnitude to 1.13 × 10<sup>4</sup> <!-->Pa. Compared to the reference lubricants, elastohydrodynamic friction was reduced by more than 90<!--> <!-->%. Nevertheless, due to the pronounced shear-thinning behavior, a weight average molar mass of 19<!--> <!-->kg<!--> <!-->mol<sup>-1</sup> seems to represent a threshold for relevant lubricant film formation in elastohydrodynamically lubricated contacts. Overall, the results show that the combination of hydroxyethyl cellulose and glycerol is well suited for viscosity modification of aqueous lubricants.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110563"},"PeriodicalIF":6.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-31DOI: 10.1016/j.triboint.2025.110538
Sara Zahmatkesh, Reza Rizvi
This study presents a high-velocity tribotest using Bruker UMT Tribolab to evaluate the ice traction of rubber composites. Lab-scale tribotests are essential for developing anti-slip materials for footwear. Reciprocating and rotational movements were studied on ice, along with the physical phenomena influencing friction, optimizing dwell time and load control parameters. GF-TPU composites and commercial winter boots (Green Diamond® and Arctic Grip Vibram®) were tested for validation. The addition of 10 wt% glass fibers to TPU increased static friction by 300 % and kinetic friction by 400 %, enhancing stick-slip behavior. SiC-based texturing in Green Diamond composites improved static friction by 160 % and kinetic friction by 970 %. Arctic Grip samples showed a 440 % increase in static friction and over 1000 % in kinetic friction.
{"title":"Evaluating surface texturing technologies of rubber composites on ice using a novel high-velocity tribotest method","authors":"Sara Zahmatkesh, Reza Rizvi","doi":"10.1016/j.triboint.2025.110538","DOIUrl":"10.1016/j.triboint.2025.110538","url":null,"abstract":"<div><div>This study presents a high-velocity tribotest using Bruker UMT Tribolab to evaluate the ice traction of rubber composites. Lab-scale tribotests are essential for developing anti-slip materials for footwear. Reciprocating and rotational movements were studied on ice, along with the physical phenomena influencing friction, optimizing dwell time and load control parameters. GF-TPU composites and commercial winter boots (Green Diamond® and Arctic Grip Vibram®) were tested for validation. The addition of 10 wt% glass fibers to TPU increased static friction by 300 % and kinetic friction by 400 %, enhancing stick-slip behavior. SiC-based texturing in Green Diamond composites improved static friction by 160 % and kinetic friction by 970 %. Arctic Grip samples showed a 440 % increase in static friction and over 1000 % in kinetic friction.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"206 ","pages":"Article 110538"},"PeriodicalIF":6.1,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143330525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-30DOI: 10.1016/j.triboint.2025.110565
Duncai Bao , Boxiang Hong , Chenfeng Yuan , Lipeng Jiang , Xun Zhang , Qian Li , Xiang Li , Zhaoxue Deng
Magnesium alloys are easily exposed to wear and corrosion during service life, hindering their applications. Herein, the Ti-Ni-Cu coatings were designed. Thermal-mechanical simulation of laser cladding on magnesium alloy surface was performed for exploring the optimal cladding parameters. Form the simulation results, laser power of 1200 W, scanning speed of 20 mm/s and spot diameter of 3 mm were applied. A series of characterizations were performed to study the microstructure, corrosion and wear properties of the coating. The results indicated Ni52.5Ti33.5Cu14 coating presented the comprehensively enhanced wear resistance than the substrate. Specifically, an increase in coatings’ microhardness by a factor of 6 over substrate was achieved. Besides, the Icorr was one order of magnitude lower than that of the substrate.
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