Pub Date : 2025-04-08DOI: 10.1016/j.triboint.2025.110715
Yihan Wang, Yang Zhang, Tianmin Shao
In this work, tribological behaviors of solution strengthening Co-based superalloy HA188 were investigated at 900℃, 1000℃ and 1100℃. Si3N4 and HA188 were chosen as the counterpart respectively to evaluate the influence of counterpart materials on the sliding wear behaviors. It was found that the formation and destruction of tribo-layer are the dominating factor in the high temperature wear process. The composition and structure of tribo-layer are controlled by oxidation products of HA188 at different temperature. Tribo-layers are composed of NiCoCr-spinels at 900℃ and 1000℃. However, at 1100℃, the tribo-layer composition transfers to Cr₂O₃, which is attributed to the substantial diffusion of Cr to the surface. Moreover, counterpart materials affect the homogeneity and compactness of the tribo-layers. Harder counterparts generate greater stress and deformation in tribo-layer and HA188 substrate, leading to the failure of the tribo-layer and the increase in wear rate.
{"title":"High temperature tribological behaviors of Co-based superalloy Haynes 188","authors":"Yihan Wang, Yang Zhang, Tianmin Shao","doi":"10.1016/j.triboint.2025.110715","DOIUrl":"10.1016/j.triboint.2025.110715","url":null,"abstract":"<div><div>In this work, tribological behaviors of solution strengthening Co-based superalloy HA188 were investigated at 900℃, 1000℃ and 1100℃. Si<sub>3</sub>N<sub>4</sub> and HA188 were chosen as the counterpart respectively to evaluate the influence of counterpart materials on the sliding wear behaviors. It was found that the formation and destruction of tribo-layer are the dominating factor in the high temperature wear process. The composition and structure of tribo-layer are controlled by oxidation products of HA188 at different temperature. Tribo-layers are composed of NiCoCr-spinels at 900℃ and 1000℃. However, at 1100℃, the tribo-layer composition transfers to Cr₂O₃, which is attributed to the substantial diffusion of Cr to the surface. Moreover, counterpart materials affect the homogeneity and compactness of the tribo-layers. Harder counterparts generate greater stress and deformation in tribo-layer and HA188 substrate, leading to the failure of the tribo-layer and the increase in wear rate.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110715"},"PeriodicalIF":6.1,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800096","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 : 2025-04-08DOI: 10.1016/j.triboint.2025.110711
Dongfang Zeng , Yan Xu , Zhisheng Liu , Yuanbin Zhang , Lang Zou , Liantao Lu
Given the early stages of widespread adoption of swage-locking pinned connections in rail vehicle structures, research on their fatigue failure behavior remains scarce. This study investigates the fretting fatigue behavior of aluminum alloy–steel connections fastened by swage-locking pins through experiments and numerical analysis. It involved fatigue experiments under tension loading, fretting wear and fatigue analyses, followed by fatigue crack initiation prediction. Results show that the contact surface of clamped plates can be divided into the stick, slip, and open zones, with fretting wear occurring within the slip zone of aluminum alloy plate. Fretting fatigue cracks typically initiate within the slip zone near the stick-slip boundary, specifically at wear scars edges. A finite element model was developed to analyze contact status and stress states of test connections, with the friction coefficient at the aluminum alloy-steel interface optimized based on measured stick zone sizes. Results show the fatigue crack initiation of test connections is predominantly influenced by tensile stresses. Consequently, the SWT multiaxial fatigue criterion, combined with the critical plane method, can be used to predict crack initiation. The predicted crack initiation sites, angles, and fatigue strengths closely matched experimental results, with errors below 20 %, 5 %, and 7 %, respectively.
{"title":"Fretting fatigue analysis and strength evaluation for swage-locking pinned aluminum alloy–steel connections under tension loading","authors":"Dongfang Zeng , Yan Xu , Zhisheng Liu , Yuanbin Zhang , Lang Zou , Liantao Lu","doi":"10.1016/j.triboint.2025.110711","DOIUrl":"10.1016/j.triboint.2025.110711","url":null,"abstract":"<div><div>Given the early stages of widespread adoption of swage-locking pinned connections in rail vehicle structures, research on their fatigue failure behavior remains scarce. This study investigates the fretting fatigue behavior of aluminum alloy–steel connections fastened by swage-locking pins through experiments and numerical analysis. It involved fatigue experiments under tension loading, fretting wear and fatigue analyses, followed by fatigue crack initiation prediction. Results show that the contact surface of clamped plates can be divided into the stick, slip, and open zones, with fretting wear occurring within the slip zone of aluminum alloy plate. Fretting fatigue cracks typically initiate within the slip zone near the stick-slip boundary, specifically at wear scars edges. A finite element model was developed to analyze contact status and stress states of test connections, with the friction coefficient at the aluminum alloy-steel interface optimized based on measured stick zone sizes. Results show the fatigue crack initiation of test connections is predominantly influenced by tensile stresses. Consequently, the SWT multiaxial fatigue criterion, combined with the critical plane method, can be used to predict crack initiation. The predicted crack initiation sites, angles, and fatigue strengths closely matched experimental results, with errors below 20 %, 5 %, and 7 %, respectively.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110711"},"PeriodicalIF":6.1,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807735","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}
A new kind of multi-phase ceramic composite comprising of a SiC matrix reinforced with Si3N4 and BN was prepared by in-situ formation during nitridation of Si metal and B2O3. Al2O3 was used as a sintering additive as well as to improve oxidation and corrosion resistance. XRD and SEM techniques were effectively utilized to confirm phases and analyse the evolutionary changes in microstructure. Dry wear tests were conducted to evaluate the composite’s wear resistance. It was discovered that the SiC-Si3N4–BN–Al2O3 composite possessed exceptional properties, such as high hardness, high abrasive wear resistance, and low coefficient of friction. The examination of surface topography using atomic force microscopy indicates that the composites exhibit improved smoothness and enhanced capacity for load bearing. These characteristics make the composite material highly promising for diverse tribological applications. Furthermore, the strengthening and wear mechanisms of this composite were analysed and discussed in this paper.
{"title":"Tribological performance and surface morphological analysis of in-situ synthesized BN-Si3N4 reinforced SiC-Al2O3 ceramic matrix composites","authors":"Aman Singh , Vineet Kumar , Jyoti , Raj Kumar Chaturvedi , Manvandra Kumar Singh , Jitendra Kumar Katiyar , Vinay Kumar Singh","doi":"10.1016/j.triboint.2025.110703","DOIUrl":"10.1016/j.triboint.2025.110703","url":null,"abstract":"<div><div>A new kind of multi-phase ceramic composite comprising of a SiC matrix reinforced with Si<sub>3</sub>N<sub>4</sub> and BN was prepared by in-situ formation during nitridation of Si metal and B<sub>2</sub>O<sub>3</sub>. Al<sub>2</sub>O<sub>3</sub> was used as a sintering additive as well as to improve oxidation and corrosion resistance. XRD and SEM techniques were effectively utilized to confirm phases and analyse the evolutionary changes in microstructure. Dry wear tests were conducted to evaluate the composite’s wear resistance. It was discovered that the SiC-Si<sub>3</sub>N<sub>4</sub>–BN–Al<sub>2</sub>O<sub>3</sub> composite possessed exceptional properties, such as high hardness, high abrasive wear resistance, and low coefficient of friction. The examination of surface topography using atomic force microscopy indicates that the composites exhibit improved smoothness and enhanced capacity for load bearing. These characteristics make the composite material highly promising for diverse tribological applications. Furthermore, the strengthening and wear mechanisms of this composite were analysed and discussed in this paper.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110703"},"PeriodicalIF":6.1,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800094","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 : 2025-04-07DOI: 10.1016/j.triboint.2025.110702
Nian Liu , Haoran Wang , Ling Lei , Huilong Jiang , Yongjie Zhang , Junfeng Xiao , Jianguo Zhang , Xiao Chen , Jianfeng Xu
Experiments and molecular dynamics (MD) simulations are combined to study the newly developed medium vacuum ultraviolet (UV)-assisted polishing (MV-UVAP) for diamond. The material removal rate (MRR) reaches over 7.0 μm/h and it is mainly determined by the diamond graphitization rate. The damage-free characteristic is confirmed by Raman and TEM measurement. MD simulation reveals the removal mechanism in MV-UVAP from an atomistic aspect. With synergic action of UV energy, O radical oxidation, and drawing force of Si-O-C bonds, lots of C atoms get removed from diamond. As large amounts of C-C bonds get rupture among this atom by atom removal process, the diamond structure is reconstructed into graphite, which is key for achieving high MRR without generating damage layers.
{"title":"Highly efficient medium vacuum UV-assisted polishing of diamond via C-C bond breakage stimulated graphitization","authors":"Nian Liu , Haoran Wang , Ling Lei , Huilong Jiang , Yongjie Zhang , Junfeng Xiao , Jianguo Zhang , Xiao Chen , Jianfeng Xu","doi":"10.1016/j.triboint.2025.110702","DOIUrl":"10.1016/j.triboint.2025.110702","url":null,"abstract":"<div><div>Experiments and molecular dynamics (MD) simulations are combined to study the newly developed medium vacuum ultraviolet (UV)-assisted polishing (MV-UVAP) for diamond. The material removal rate (MRR) reaches over 7.0 μm/h and it is mainly determined by the diamond graphitization rate. The damage-free characteristic is confirmed by Raman and TEM measurement. MD simulation reveals the removal mechanism in MV-UVAP from an atomistic aspect. With synergic action of UV energy, O radical oxidation, and drawing force of Si-O-C bonds, lots of C atoms get removed from diamond. As large amounts of C-C bonds get rupture among this atom by atom removal process, the diamond structure is reconstructed into graphite, which is key for achieving high MRR without generating damage layers.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110702"},"PeriodicalIF":6.1,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800095","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 : 2025-04-07DOI: 10.1016/j.triboint.2025.110679
Bilsay Sümer , Gülçin Şefiye Aşkın
The elasticity and frictional dynamics of a cochlear implant electrode array (EA) with different wire shapes are investigated by numerical and experimental analysis. Finite element method (FEM) analysis with varying wavelengths under large deformations indicates that the corrugated wire exhibits enhanced flexibility in both the transverse and longitudinal directions, while the buckling limit of the EA is governed by the wavelength of the wires. The friction experiments are carried out on a flat surface and an artificial cochlea model at different preloads, speeds and surface conditions, and the resulting data are analyzed using friction loops. It is found that wavy wired EA has a lower friction response and insertion force, while they are more prone to tip buckling and electrode array tip fold-over.
{"title":"A tribological investigation of cochlear implant electrode arrays with different wire shapes","authors":"Bilsay Sümer , Gülçin Şefiye Aşkın","doi":"10.1016/j.triboint.2025.110679","DOIUrl":"10.1016/j.triboint.2025.110679","url":null,"abstract":"<div><div>The elasticity and frictional dynamics of a cochlear implant electrode array (EA) with different wire shapes are investigated by numerical and experimental analysis. Finite element method (FEM) analysis with varying wavelengths under large deformations indicates that the corrugated wire exhibits enhanced flexibility in both the transverse and longitudinal directions, while the buckling limit of the EA is governed by the wavelength of the wires. The friction experiments are carried out on a flat surface and an artificial cochlea model at different preloads, speeds and surface conditions, and the resulting data are analyzed using friction loops. It is found that wavy wired EA has a lower friction response and insertion force, while they are more prone to tip buckling and electrode array tip fold-over.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110679"},"PeriodicalIF":6.1,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800097","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 : 2025-04-05DOI: 10.1016/j.triboint.2025.110701
Yanliang Shen , Yanhua Wang , Chen Zhao , Xingwei Wang , Qiangliang Yu , Meirong Cai , Bo Yu , Feng Zhou
A complete silica microcapsule filled with PAO6 oil was synthesized by emulsion-templated sol-gel method. The average diameter of microcapsule was about 20 µm, with encapsulation capacity of 70 %. The microcapsules were well-dispersed in aqueous solution and fully compatible with waterborne epoxy emulsion, making it suitable for building VOC-free self-lubricating coatings. With 5 wt% microcapsule, the self-lubricating coating achieved an exceptionally low friction coefficient at about 0.02, approximately 2.6 % of that of the blank coating without microcapsules. The wear volume could barely be measured. The ultra-fast response ability was robust, as confirmed by the negligible running time throughout the continuous start-stop sliding tests. This oil-filled silica microcapsule has great potential for developing high performance and VOC-free self-lubricating coatings.
{"title":"Ultra-low friction, ultra-fast response and low-VOC self-lubricating coating based on oil-filled silica microcapsules","authors":"Yanliang Shen , Yanhua Wang , Chen Zhao , Xingwei Wang , Qiangliang Yu , Meirong Cai , Bo Yu , Feng Zhou","doi":"10.1016/j.triboint.2025.110701","DOIUrl":"10.1016/j.triboint.2025.110701","url":null,"abstract":"<div><div>A complete silica microcapsule filled with PAO6 oil was synthesized by emulsion-templated sol-gel method. The average diameter of microcapsule was about 20 µm, with encapsulation capacity of 70 %. The microcapsules were well-dispersed in aqueous solution and fully compatible with waterborne epoxy emulsion, making it suitable for building VOC-free self-lubricating coatings. With 5 wt% microcapsule, the self-lubricating coating achieved an exceptionally low friction coefficient at about 0.02, approximately 2.6 % of that of the blank coating without microcapsules. The wear volume could barely be measured. The ultra-fast response ability was robust, as confirmed by the negligible running time throughout the continuous start-stop sliding tests. This oil-filled silica microcapsule has great potential for developing high performance and VOC-free self-lubricating coatings.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110701"},"PeriodicalIF":6.1,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792736","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 : 2025-04-03DOI: 10.1016/j.triboint.2025.110678
Meijun Feng , Mouji Li , Zhuanli Zhang , Ketian Gao , Xueyan Gong , Wufang Yang , Yanhua Liu , Jianbin Zhang , Zhengfeng Ma , Wenwen Zhao
Hydration lubrication has attracted significant research interest due to its environmentally friendly characteristics, low coefficient of friction (COF), and clean, green nature. While, achieving a stable, low-friction water lubrication system with high load-bearing capacity and long service life remains a key challenge. Leveraging the hydrolytic properties of triisopropylsilyl acrylate (TIPSA), a self-renewing, low-friction hydration lubrication interface using a soft-hard composite friction (SHCF) coating strategy was developed. Their comprehensive physicochemical and mechanical properties were analyzed through FT-IR, XPS, FE-SEM, CA, tensile testing, and depth-sensing indentation (DSI) techniques. Notably, by controlling interfacial degradation, the SHCF coating achieved a stable hydration layer that enhanced lubrication and an undegraded bottom layer that provided robust load-bearing support. Testing with a ball-on-disk reciprocating friction prototype demonstrated a COF as low as 0.02 under 30 N (1.59 MPa) load. Furthermore, due to its self-renewing micro-scale interface, the coating maintained excellent durability, preserving its low-friction properties for up to 10 hours (36000 cycles). This study presents an effective approach to constructing stable, water-lubricated coatings with low friction, high load capacity, and extended service life.
{"title":"Development of self-renewing soft-hard composite coating for stable hydration lubrication with high load capacity and extended durability","authors":"Meijun Feng , Mouji Li , Zhuanli Zhang , Ketian Gao , Xueyan Gong , Wufang Yang , Yanhua Liu , Jianbin Zhang , Zhengfeng Ma , Wenwen Zhao","doi":"10.1016/j.triboint.2025.110678","DOIUrl":"10.1016/j.triboint.2025.110678","url":null,"abstract":"<div><div>Hydration lubrication has attracted significant research interest due to its environmentally friendly characteristics, low coefficient of friction (COF), and clean, green nature. While, achieving a stable, low-friction water lubrication system with high load-bearing capacity and long service life remains a key challenge. Leveraging the hydrolytic properties of triisopropylsilyl acrylate (TIPSA), a self-renewing, low-friction hydration lubrication interface using a soft-hard composite friction (SHCF) coating strategy was developed. Their comprehensive physicochemical and mechanical properties were analyzed through FT-IR, XPS, FE-SEM, CA, tensile testing, and depth-sensing indentation (DSI) techniques. Notably, by controlling interfacial degradation, the SHCF coating achieved a stable hydration layer that enhanced lubrication and an undegraded bottom layer that provided robust load-bearing support. Testing with a ball-on-disk reciprocating friction prototype demonstrated a COF as low as 0.02 under 30 N (1.59 MPa) load. Furthermore, due to its self-renewing micro-scale interface, the coating maintained excellent durability, preserving its low-friction properties for up to 10 hours (36000 cycles). This study presents an effective approach to constructing stable, water-lubricated coatings with low friction, high load capacity, and extended service life.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110678"},"PeriodicalIF":6.1,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807736","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 : 2025-04-03DOI: 10.1016/j.triboint.2025.110700
Taikang Shi , Yao Li , Kuo Zhang , Mengyang Li , Yefei Geng , Xin Zhou , Ting Guo , Yajie Guo , Xiaofeng Dang
In this study, Mo-Si-B alloy coatings were in situ laser cladded on pure Mo substrate using cost-effective blended Mo, Si, and B4C powders. Mo-Si-B coatings with minimized solidification defects exhibit a dendritic morphology that consists of coarse α-Mo dendrite cores and fine-grained interdendritic Mo3Si-Mo5SiB2 eutectics, with a small amount of carbides. Compared to the pure Mo substrate, the Mo-Si-B coatings exhibit higher microhardness due to the nanohardness of interdendritic eutectics ~2.4 times greater than the α-Mo phase and showcase superior wear resistance, reducing the coefficient of friction by 72.4% and the wear rate by 39.8%. The enhanced wear resistance of Mo-Si-B coatings is attributed to the presence of hard intermetallic compounds and the formation of a self-lubricating oxidation film.
{"title":"Microstructure and wear resistance of in situ synthesized Mo-Si-B coatings through laser cladding","authors":"Taikang Shi , Yao Li , Kuo Zhang , Mengyang Li , Yefei Geng , Xin Zhou , Ting Guo , Yajie Guo , Xiaofeng Dang","doi":"10.1016/j.triboint.2025.110700","DOIUrl":"10.1016/j.triboint.2025.110700","url":null,"abstract":"<div><div>In this study, Mo-Si-B alloy coatings were in situ laser cladded on pure Mo substrate using cost-effective blended Mo, Si, and B<sub>4</sub>C powders. Mo-Si-B coatings with minimized solidification defects exhibit a dendritic morphology that consists of coarse α-Mo dendrite cores and fine-grained interdendritic Mo<sub>3</sub>Si-Mo<sub>5</sub>SiB<sub>2</sub> eutectics, with a small amount of carbides. Compared to the pure Mo substrate, the Mo-Si-B coatings exhibit higher microhardness due to the nanohardness of interdendritic eutectics ~2.4 times greater than the α-Mo phase and showcase superior wear resistance, reducing the coefficient of friction by 72.4% and the wear rate by 39.8%. The enhanced wear resistance of Mo-Si-B coatings is attributed to the presence of hard intermetallic compounds and the formation of a self-lubricating oxidation film.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110700"},"PeriodicalIF":6.1,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783562","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 : 2025-04-02DOI: 10.1016/j.triboint.2025.110685
A. Zabihi , J. Juoksukangas , J. Hintikka , T. Salminen , A. Mäntylä , J. Vaara , T. Frondelius , M. Vippola
Fretting degradation of self-mated quenched and tempered steel was studied by varying loading conditions via imposed tangential displacement amplitude in oil-lubricated flat-on-flat contact. Detailed microscopic characterization showed the effects of tangential loading and the presence of oil at the interface on (sub)surface damage. A thin, cracked carbonaceous layer, arising from oil decomposition, was detected at adhesion spots in the mixed slip-stick regime. Furthermore, surface oxidation was noticed at the highest imposed displacement amplitude of 45 µm in gross slip, despite the presence of oil. Based on the crack analysis, a substantial increase in crack size was observed by transitioning from mixed slip-stick to gross slip.
{"title":"Fretting degradation in large flat-on-flat contact under oil lubrication: Effect of displacement amplitude","authors":"A. Zabihi , J. Juoksukangas , J. Hintikka , T. Salminen , A. Mäntylä , J. Vaara , T. Frondelius , M. Vippola","doi":"10.1016/j.triboint.2025.110685","DOIUrl":"10.1016/j.triboint.2025.110685","url":null,"abstract":"<div><div>Fretting degradation of self-mated quenched and tempered steel was studied by varying loading conditions via imposed tangential displacement amplitude in oil-lubricated flat-on-flat contact. Detailed microscopic characterization showed the effects of tangential loading and the presence of oil at the interface on (sub)surface damage. A thin, cracked carbonaceous layer, arising from oil decomposition, was detected at adhesion spots in the mixed slip-stick regime. Furthermore, surface oxidation was noticed at the highest imposed displacement amplitude of 45 µm in gross slip, despite the presence of oil. Based on the crack analysis, a substantial increase in crack size was observed by transitioning from mixed slip-stick to gross slip.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110685"},"PeriodicalIF":6.1,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783563","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}
This study directly monitored molecular structures of lubricant species during sliding using in-situ surface-enhanced Raman spectroscopy (SERS) with plasmonic sensors developed by our research group. This method, characterized by exceptional sensitivity to interfacial chemical structures and high temporal resolution (1 s), facilitated tracking changes in lubricant species. Results for pure dodecane, used as the base oil for the lubricant, revealed immediate degradation upon sliding, forming amorphous carbon with benzene rings. This methodology provides the first observation of carbon degradation with high temporal resolution. In contrast, for the lubricant containing lauric acid, a surface-active additive at the iron interface, lauric acid primarily coordinated to the iron substrate, in bidentate coordination as iron laurate before sliding, with this structure persisting during sliding. This indicates that the carboxylate ions (COO−) function as a lubricating film by maintaining coordination with the iron substrate. In addition, continuously measured SERS spectra exhibited dynamic changes in the region corresponding to COO−, indicating that the degree of molecular interaction between carboxylate ions changes over time, with the bidentate coordination of COO− remaining predominant. This finding contributes to optimizing the formulation of lubricant blends with multiple additives. In conclusion, this study provided direct observation of chemical structures during sliding, which were previously only inferred owing to observational challenges. This work is expected to significantly enhance the molecular-level understanding of various base oils and additives under frictional conditions, facilitating the molecular design and formulation of more effective lubricants.
{"title":"In-situ molecular-level observation of lubricant species at tribological interface using surface-enhanced Raman spectroscopy","authors":"Subaru Sawaki , Masahiro Yanagisawa , Masahiro Kunimoto , Takayuki Homma","doi":"10.1016/j.triboint.2025.110695","DOIUrl":"10.1016/j.triboint.2025.110695","url":null,"abstract":"<div><div>This study directly monitored molecular structures of lubricant species during sliding using in-situ surface-enhanced Raman spectroscopy (SERS) with plasmonic sensors developed by our research group. This method, characterized by exceptional sensitivity to interfacial chemical structures and high temporal resolution (1 s), facilitated tracking changes in lubricant species. Results for pure dodecane, used as the base oil for the lubricant, revealed immediate degradation upon sliding, forming amorphous carbon with benzene rings. This methodology provides the first observation of carbon degradation with high temporal resolution. In contrast, for the lubricant containing lauric acid, a surface-active additive at the iron interface, lauric acid primarily coordinated to the iron substrate, in bidentate coordination as iron laurate before sliding, with this structure persisting during sliding. This indicates that the carboxylate ions (COO<sup>−</sup>) function as a lubricating film by maintaining coordination with the iron substrate. In addition, continuously measured SERS spectra exhibited dynamic changes in the region corresponding to COO<sup>−</sup>, indicating that the degree of molecular interaction between carboxylate ions changes over time, with the bidentate coordination of COO<sup>−</sup> remaining predominant. This finding contributes to optimizing the formulation of lubricant blends with multiple additives. In conclusion, this study provided direct observation of chemical structures during sliding, which were previously only inferred owing to observational challenges. This work is expected to significantly enhance the molecular-level understanding of various base oils and additives under frictional conditions, facilitating the molecular design and formulation of more effective lubricants.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"209 ","pages":"Article 110695"},"PeriodicalIF":6.1,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792737","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}
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