IF 6.8 1区工程技术

Friction Pub Date : 2025-04-09 DOI: 10.26599/frict.2025.9441108

Xiaoyan Ma, Qing Gao, Zhenrong Gao, Xin Fan, Min Yang, Shunhua Wang, Siming Ren, Jibin Pu

{"title":"Oxygen-induced contact evolution enables friction reduction in MoS2/Ag composite films","authors":"Xiaoyan Ma, Qing Gao, Zhenrong Gao, Xin Fan, Min Yang, Shunhua Wang, Siming Ren, Jibin Pu","doi":"10.26599/frict.2025.9441108","DOIUrl":"https://doi.org/10.26599/frict.2025.9441108","url":null,"abstract":"Molybdenum disulfide (MoS2) is widely utilized as a lubricant in aerospace, machinery, and electronics due to its unique layered structure and interlayer slip characteristics. Understanding the tribological behaviors of MoS2-based films under varying atmospheric conditions, including oxidizing and specialized atmospheres, is crucial for developing environmentally adaptive lubricants. Here, we fabricated pure MoS2 and Ag-doped MoS2/Ag composite films via magnetron sputtering, focusing on their tribological performance in argon, CO2 and O2 atmospheres. Our results demonstrate that the friction coefficients of both films in argon and CO2 are comparable to those in vacuum, with these environments promoting the formation of a continuous tribofilm on the counterpart ball surface, thereby reducing wear rates. Remarkably, in an oxygen environment, the MoS2/Ag composite film exhibits a ~50% reduction in the friction coefficient (0.027) and a threefold decrease in wear rate compared to vacuum conditions. This exceptional performance is attributed to the friction-induced metal oxide nanoparticles coated with Ag, forming a “brick-mud” structure that slides with MoS2 (002) nanosheets to achieve low friction and wear. Furthermore, the addition of Ag enhances the film’s ability to repair sliding interfaces, mitigating abrasive wear. Our study elucidates the mechanisms driving the low-friction behavior of MoS2-based films in atmospheric environments, offering valuable insights for the development of high-performance lubricants for extreme conditions.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"18 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806502","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}

引用次数: 0

Effects of contact path on lubricant distribution and EHL film formation

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-09 DOI: 10.26599/frict.2025.9441026

Xuyang Jin, Xinming Li, Linqing Bai, He Chong, Feng Guo, Gerhard Poll, Yongqiang Fu

{"title":"Effects of contact path on lubricant distribution and EHL film formation","authors":"Xuyang Jin, Xinming Li, Linqing Bai, He Chong, Feng Guo, Gerhard Poll, Yongqiang Fu","doi":"10.26599/frict.2025.9441026","DOIUrl":"https://doi.org/10.26599/frict.2025.9441026","url":null,"abstract":"The dynamic motion of the rolling elements in rolling bearings leads to variations in the contact paths. The displacement of the rolling tracks and the contact width between adjacent rolling elements redistribute the lubricant, consequently influencing film formation. To reproduce this process, an auxiliary ball is introduced into the conventional ball-on-disc test device. By adjusting the positions and loading conditions of the auxiliary balls, the influences of the offset distance (L) and contact width on lubricant redistribution and film formation can be experimentally observed. The results demonstrate that as L increases, both the inlet lubricant supply and the lubrication state improve. At high loads, the auxiliary ball generates a wider rolling track, resulting in a decrease in film thickness due to inadequate inlet lubricant supply. Furthermore, numerical simulations were conducted to validate these observations. The results confirm that dynamic ball motion significantly influences lubricant redistribution and plays a vital role in determining film thickness. The underlying mechanisms were analyzed and elucidated. The findings provide valuable insights into the lubrication behavior of rolling bearings induced by the dynamic motion of rolling elements.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"108 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806503","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}

引用次数: 0

Calcium ions combining epigallocatechin 3-gallate to enhance saliva lubrication

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-09 DOI: 10.26599/frict.2025.9441109

Yue Tang, Lei Lei, You Zhou, Yulong Zhou, Jing Zheng, Zhongrong Zhou

{"title":"Calcium ions combining epigallocatechin 3-gallate to enhance saliva lubrication","authors":"Yue Tang, Lei Lei, You Zhou, Yulong Zhou, Jing Zheng, Zhongrong Zhou","doi":"10.26599/frict.2025.9441109","DOIUrl":"https://doi.org/10.26599/frict.2025.9441109","url":null,"abstract":"This in vitro study investigated the effect of combination of calcium ions (Ca2+) with epigallocatechin 3-gallate (EGCG) on the adsorption and lubrication of salivary proteins as well as the bacterial growth in saliva, aiming to explore a feasible approach to enhance saliva lubrication for xerostomia treatment. The adsorption and lubrication behavior of salivary proteins were examined using atomic force microscope, quartz-crystal microbalance with dissipation and nano-indentation/scratch techniques, and the Streptococcus mutans activity in saliva was evaluated by using flat colony counting method. Results showed that although improving the adsorption and lubrication of salivary proteins, extra addition of Ca2+ in saliva causes flagrant bacterial proliferation. The lubrication benefits of adding 6 mM Ca2+ outweigh the risks of bacterial growth, while a concomitant addition of EGCG in saliva at concentrations of ≥ 0.046 mM inhibits the resulting bacterial proliferation. Nevertheless, introduction of EGCG into saliva has the potential to coarsen salivary pellicles and affect oral perception, and an applicable concentration range for the EGCG in combination with 6 mM Ca2+ was found to be 0.046 mM to 0.08 mM. Moreover, Ca2+ combining EGCG contributes to an increase in the lubricity of the two-layered salivary pellicles obtained from selective physisorption of salivary proteins through a mechanism that induces salivary protein aggregation and then increases the thickness, viscoelasticity, and energy dissipation of the outer pellicle layer. Consequently, the combination of Ca2+ with sub-perceptual EGCG has an encouraging tribological role in saliva lubrication, demonstrating great promise for xerostomia treatment.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"2 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806500","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}

引用次数: 0

Bio-inspired ceramic scaffold reinforced PTFE composites achieving near-zero wear and self-lubrication under extreme conditions

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-09 DOI: 10.26599/frict.2025.9441110

Lei Lei, Qian Cao, Yuchi Wu, Mintang Liu, Jing Zheng, Yuanyuan Mei, Zhongrong Zhou

{"title":"Bio-inspired ceramic scaffold reinforced PTFE composites achieving near-zero wear and self-lubrication under extreme conditions","authors":"Lei Lei, Qian Cao, Yuchi Wu, Mintang Liu, Jing Zheng, Yuanyuan Mei, Zhongrong Zhou","doi":"10.26599/frict.2025.9441110","DOIUrl":"https://doi.org/10.26599/frict.2025.9441110","url":null,"abstract":"The development of high-performance polytetrafluoroethylene (PTFE) composites with excellent wear resistance and self-lubrication under heavy-load and high-speed conditions is urgently required for advanced tribological applications in many fields including aviation and aerospace, but remains a challenge. Human enamel, a natural composite capable of enduring millions of chewing cycles under pressures up to ~2.5 GPa, serves as an ideal model for advanced wear-resistant composites. Herein, a biomimetic design strategy is proposed to create PTFE composites with a cellular-structured ceramic scaffold reinforcement microstructure, inspired by the anti-wear effect of enamel rod/inter-rod structure. By utilizing the preferential load support effect and debris size control mechanism of ceramic scaffold, the bio-inspired composites achieve excellent wear resistance with effective self-lubrication. Furthermore, a polydopamine modification technology for PTFE component is employed to enhance the adhesion and stability of PTFE transfer films, thereby improving the self-lubrication performance of the composites. Consequently, the resulting composites exhibit outstanding tribological properties, especially characterized by near-zero wear and good self-lubricity under heavy loads and high speeds. This work will advance the development of high-performance self-lubricating composites suitable for extreme conditions. Furthermore, the proposed design strategy is expected to be applicable to other biological prototypes, enabling the creation of diverse high-performance functional composites.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"14 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806501","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}

引用次数: 0

A generalized friction law depicting the thermal effects at chemical bonding interface

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-09 DOI: 10.26599/frict.2025.9441031

Yang Wang, Yexin Li, Xiao Huang, Jingxiang Xu, Yusuke Ootani, Nobuki Ozawa, Koshi Adachi, Linmao Qian, Wen Wang, Momoji Kubo

引用次数: 0

Evolution of nanocrystalline “glaze” layers and subsurfaces ultrafine grain layer in high-temperature sliding wear 高温滑动磨损中纳米晶 "釉 "层和亚表面超细晶粒层的演变

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-09 DOI: 10.26599/frict.2025.9441107

Shuai Yang, Siyang Gao, Weihai Xue, Bi Wu, Deli Duan

{"title":"Evolution of nanocrystalline “glaze” layers and subsurfaces ultrafine grain layer in high-temperature sliding wear","authors":"Shuai Yang, Siyang Gao, Weihai Xue, Bi Wu, Deli Duan","doi":"10.26599/frict.2025.9441107","DOIUrl":"https://doi.org/10.26599/frict.2025.9441107","url":null,"abstract":"The transition from severe to mild wear is an interesting phenomenon, which is usually attributed to the nanocrystalline “glaze” layer and subsurface ultrafine grain layer. However, the formation of “glaze” layers and subsurfaces and their effect on wear mechanism are still unclear. The high-temperature tribological behaviors of the DD5 single-crystal superalloy and the electro spark-deposited NiAlTa coating were investigated at 25~1000 ℃ by a high-temperature tribometer. The microstructures, chemical compositions, and grain orientations of the “glaze” layers and subsurfaces were studied. NiAlTa coatings show excellent wear resistance compared with DD5 superalloys, which is attributed to the excellent high-temperature softening resistance, high microhardness of the “glaze” layer, and good strain-hardening capacity of the subsurface ultrafine grain layer. Quantitative analysis reveals that whether the oxides on the wear surface play an antiwear lubrication role or not depends on the content and properties of the oxides. The 100-fold difference in wear rate indicates that the high-temperature wear resistance of material is related to the chemical composition and microstructure of the “glaze” layers and subsurfaces. A mechanistic model is proposed to describe the evolution of nanocrystalline “glaze” layers and subsurfaces ultrafine grain layer “glaze” layers.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"30 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806498","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}

引用次数: 0

A glance into the boundary lubrication mechanism of PVA hydrogel after the reduction of interstitial fluid pressurization

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-03 DOI: 10.26599/frict.2025.9441106

Daniel Němeček, David Nečas, Hironori Shinmori, Seido Yarimitsu, Max Marian, Martin Vrbka, Yoshinori Sawae, Ivan Křupka, Martin Hartl

引用次数: 0

Analytical model for revealing tool wear law during edge trimming of carbon fiber reinforced plastics composites

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-03 DOI: 10.26599/frict.2025.9440992

Yue Li, Hongyan Zhou, Boyu Zhang, Kai Sun, Xigao Jian

{"title":"Analytical model for revealing tool wear law during edge trimming of carbon fiber reinforced plastics composites","authors":"Yue Li, Hongyan Zhou, Boyu Zhang, Kai Sun, Xigao Jian","doi":"10.26599/frict.2025.9440992","DOIUrl":"https://doi.org/10.26599/frict.2025.9440992","url":null,"abstract":"This study proposes a novel tool wear model for the edge trimming process of carbon fiber-reinforced plasticities (CFRPs). The main innovation is that the model considers the actual wear state of both the planar flank face and the semicylindrical cutting edge. In addition, for the whole wear process, the model illustrates the dynamic wear condition by introducing a varying wear coefficient determined by the instantaneous force‒temperature condition and relative movement distance. The analytical results of the tool wear law suggest that cutting edge wear depends on tool nose rigidity and the practical contact distance with the CFRP workpiece mainly. To suppress cutting edge wear, reducing the rake angle and flank angle to improve rigidity and selecting a low spindle speed and high feed rate to decrease the practical cutting distance are recommended. The wear of the flank face is mainly determined by the flank angle and bouncing back height of the machined surface. To reduce its wear, a large flank angle, high spindle speed, and low feed rate are recommended. Since the strategies for reducing the wear of the cutting edge and flank faces are contradictory, to reduce tool wear more effectively, reducing cutting-edge wear is prioritized.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"33 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766918","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}

引用次数: 0

A distinctive material removal mode in chemical mechanical polishing besides chemical bonding and mechanical plowing: Shear slipping

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-02 DOI: 10.26599/frict.2025.9441104

Yushan Chen, Liuyue Xu, Yuan Wu, Liao Zhou, Yuting Wei, Zihan Zheng, Hui Li, Liang Jiang, Linmao Qian

{"title":"A distinctive material removal mode in chemical mechanical polishing besides chemical bonding and mechanical plowing: Shear slipping","authors":"Yushan Chen, Liuyue Xu, Yuan Wu, Liao Zhou, Yuting Wei, Zihan Zheng, Hui Li, Liang Jiang, Linmao Qian","doi":"10.26599/frict.2025.9441104","DOIUrl":"https://doi.org/10.26599/frict.2025.9441104","url":null,"abstract":"Layered materials, such as bismuth, offer exceptional properties for future integrated circuits (IC). Research is underway to adapt these materials to conventional IC manufacturing processes, like chemical mechanical polishing (CMP). However, CMP of layered materials remains underexplored. This study chose bismuth as a representative to investigate its CMP properties. The results reveal that the material removal rate (MRR) increases rapidly and stabilizes as the H2O2 concentration increases. An ultra-high MRR exceeding 10 μm/min is achieved, which is significantly higher than the typical <1 μm/min. A distinctive material removal mode is proposed: shear slipping. This mode differs from the previously reported chemical bonding and mechanical plowing. Specifically, bismuth is oxidized by H2O2 to form a Bi2O3 surface film, which has a weak interaction with the bismuth substrate, creating a low-shear interface. Under the shearing action of the polishing pad asperities, the surface film slips relative to the substrate, distinct from forming and tearing chemical bonds via chemical bonding and breaking the weakened surface in-plane via mechanical plowing. Consequently, material removal is achieved as micron-sized debris. Furthermore, the shear slipping mode may apply to other layered materials. Adding lubricants and optimizing the polishing pad may help control layered materials removal in CMP.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"22 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143758238","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}

引用次数: 0

IPN-PUA: An ultra-low density self-lubricating composite with IPN structure–liquid lubricant coupling mechanism

IF 6.8 1区工程技术

Friction Pub Date : 2025-04-01 DOI: 10.26599/frict.2025.9440997

Weihua Cao, Xiao Yang, Haiwang Wang, Yu Dong, Changxin Liu, Bingli Fan, Xiaowen Qi

{"title":"IPN-PUA: An ultra-low density self-lubricating composite with IPN structure–liquid lubricant coupling mechanism","authors":"Weihua Cao, Xiao Yang, Haiwang Wang, Yu Dong, Changxin Liu, Bingli Fan, Xiaowen Qi","doi":"10.26599/frict.2025.9440997","DOIUrl":"https://doi.org/10.26599/frict.2025.9440997","url":null,"abstract":"The goal of net zero carbon emissions is of a great concern to energy conservation and emission reduction. In aerospace and other industrial fields, one of main energy consumption forms is friction between motion pairs, although the energy consumption caused by equipment mass cannot be ignored. Therefore, ultra-low density self-lubricating composites with an interpenetrating polymer network (IPN) structure–liquid lubricant coupling mechanism are designed and prepared in this work to meet the pressing requirements of energy saving and emission reduction. The liquid lubricant is locked in situ into polyurethane acrylate (PUA) with IPN structures (IPN-PUA structures). The thermodynamic, mechanical, and tribological properties, as well as the comprehensive density‒friction properties of the material with IPN-PUA structures were studied. After the liquid lubricant is locked into the IPN-PUA structure, the material possesses not only excellent self-lubricating properties but also good micro-mechanical properties, with a coefficient of friction (COF) of 0.0938, wear rate of 6.58×10−15 m3/(N·m) and nanoindentation modulus of 4.5 GPa. Compared with other polymeric materials, such composite materials also possess an ultra-low density of 1.107 g/cm3, which contributes to their excellent versatile self-lubrication and low-density characteristics.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"143 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143745234","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}

引用次数: 0

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