Pub Date : 2026-04-01Epub Date: 2026-02-11DOI: 10.1016/j.vacuum.2026.115179
Bangle Zhu , Pengcheng Wang , Jiaming Liu , Shunming Liu , Biao Tan , Xiaoyang Sun , Yigang Wang , Yongsheng Ma , Tao Huang , Haiyi Dong
The compact vacuum systems of Diffraction-limited Storage Rings (DLSRs) necessitate the deployment of Non-Evaporable Getter (NEG) films to achieve and maintain an ultra-high vacuum (UHV) environment. The NEG films, utilized for distributed pumping on the surfaces within UHV chambers, have demonstrated significant potential for particle accelerators. They provide several advantages, including increased pumping efficiency, lower achievable pressures, reduced outgassing rates, and a reduction in secondary electron emission. The batch application of NEG films in an accelerator storage ring necessitates dedicated specialized batch production equipment and processes. In order to meet the engineering specifications for NEG films at the HEPS ring, this study has developed a multi-channel magnetron sputtering system designed for film coating purposes. The system incorporates movable solenoids, enabling the segmented deposition of NEG films on the interior surfaces of beam pipes. It is capable of coating a cumulative length of over 30 m, distributed across six channels, each 5.2 m long, in a single operational cycle. With this configuration, TiZrV films were successfully deposited inside a prototype vacuum chamber. The activation temperature for the TiZrV film was determined via in-situ X-ray photoelectron spectroscopy (XPS), indicating that the NEG film could be activated at 180 °C. The pumping speed of the NEG film was evaluated using a self-designed and built pumping testing system. The experimental findings revealed that after activation at 200 °C, the TiZrV film exhibited a pumping speed of 0.68 cm2 for H and a pumping speed of 2.36 cm2 for CO.
{"title":"Study on batch coating and vacuum performance of TiZrV Non-Evaporable Getter films","authors":"Bangle Zhu , Pengcheng Wang , Jiaming Liu , Shunming Liu , Biao Tan , Xiaoyang Sun , Yigang Wang , Yongsheng Ma , Tao Huang , Haiyi Dong","doi":"10.1016/j.vacuum.2026.115179","DOIUrl":"10.1016/j.vacuum.2026.115179","url":null,"abstract":"<div><div>The compact vacuum systems of Diffraction-limited Storage Rings (DLSRs) necessitate the deployment of Non-Evaporable Getter (NEG) films to achieve and maintain an ultra-high vacuum (UHV) environment. The NEG films, utilized for distributed pumping on the surfaces within UHV chambers, have demonstrated significant potential for particle accelerators. They provide several advantages, including increased pumping efficiency, lower achievable pressures, reduced outgassing rates, and a reduction in secondary electron emission. The batch application of NEG films in an accelerator storage ring necessitates dedicated specialized batch production equipment and processes. In order to meet the engineering specifications for NEG films at the HEPS ring, this study has developed a multi-channel magnetron sputtering system designed for film coating purposes. The system incorporates movable solenoids, enabling the segmented deposition of NEG films on the interior surfaces of beam pipes. It is capable of coating a cumulative length of over 30 m, distributed across six channels, each 5.2 m long, in a single operational cycle. With this configuration, TiZrV films were successfully deposited inside a prototype vacuum chamber. The activation temperature for the TiZrV film was determined via in-situ X-ray photoelectron spectroscopy (XPS), indicating that the NEG film could be activated at 180 °C. The pumping speed of the NEG film was evaluated using a self-designed and built pumping testing system. The experimental findings revealed that after activation at 200 °C, the TiZrV film exhibited a pumping speed of 0.68 <span><math><mi>L/s</mi><mspace></mspace></math></span>cm<sup>2</sup> for H<span><math><msub><mrow></mrow><mrow><mtext>2</mtext></mrow></msub></math></span> and a pumping speed of 2.36 <span><math><mi>L/s</mi><mspace></mspace></math></span>cm<sup>2</sup> for CO.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115179"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-19DOI: 10.1016/j.vacuum.2026.115108
Lei Xie , Jian Wang , Qiang Li , Hao Wang , Chuntao Chang , Aina He , Yaqiang Dong
This study investigates the effects of Co addition on the glass-forming ability (GFA), thermal stability, soft magnetic properties (SMPs), and crystallization behavior of the Fe84-xCoxSi2B9P3C0.5Cu1.5 (x = 0–20) nanocrystalline alloys (NAs). Research has found that rapid cooling ribbons form uneven gradient structures along the thickness direction due to the cooling rate of the wheel-side (WS) being greater than that of the free-side (FS), while the addition of Co enhances the GFA and weakens this gradient structure. Crystallization kinetics analysis shows that the nucleation and growth activation energy of the FS α-Fe(Co) crystal is higher than that of the WS, resulting in slower crystallization rate α-Fe(Co) crystals in the FS. Furthermore, Co addition leads to a more significant difference in crystallization rates between the FS and WS, thus resulting in a more uniform and finer NA nanostructure. Meanwhile, the addition of Co expands the crystallization window and inhibits the precipitation of compound phases. Finally, the NAs obtained by annealing at 480 °C for 10 min achieved excellent combination of high Bs (1.83–1.94 T) and low Hc (5–10 A/m), breaking through the trade-off between Bs and Hc in traditional soft magnetic materials. This study contributes to the understanding of the crystallization process of gradient non-uniform materials and provides guidance for the development of Fe-based NAs with high Bs and low Hc.
{"title":"Effect of Co addition on the heterogenous gradient structure, magnetic properties, and nanocrystallization process of FeSiBPCCu nanocrystalline alloys with high Fe and Cu contents","authors":"Lei Xie , Jian Wang , Qiang Li , Hao Wang , Chuntao Chang , Aina He , Yaqiang Dong","doi":"10.1016/j.vacuum.2026.115108","DOIUrl":"10.1016/j.vacuum.2026.115108","url":null,"abstract":"<div><div>This study investigates the effects of Co addition on the glass-forming ability (GFA), thermal stability, soft magnetic properties (SMPs), and crystallization behavior of the Fe<sub>84-x</sub>Co<sub>x</sub>Si<sub>2</sub>B<sub>9</sub>P<sub>3</sub>C<sub>0.5</sub>Cu<sub>1.5</sub> (x = 0–20) nanocrystalline alloys (NAs). Research has found that rapid cooling ribbons form uneven gradient structures along the thickness direction due to the cooling rate of the wheel-side (WS) being greater than that of the free-side (FS), while the addition of Co enhances the GFA and weakens this gradient structure. Crystallization kinetics analysis shows that the nucleation and growth activation energy of the FS α-Fe(Co) crystal is higher than that of the WS, resulting in slower crystallization rate α-Fe(Co) crystals in the FS. Furthermore, Co addition leads to a more significant difference in crystallization rates between the FS and WS, thus resulting in a more uniform and finer NA nanostructure. Meanwhile, the addition of Co expands the crystallization window and inhibits the precipitation of compound phases. Finally, the NAs obtained by annealing at 480 °C for 10 min achieved excellent combination of high <em>B</em><sub>s</sub> (1.83–1.94 T) and low <em>H</em><sub>c</sub> (5–10 A/m), breaking through the trade-off between <em>B</em><sub>s</sub> and <em>H</em><sub>c</sub> in traditional soft magnetic materials. This study contributes to the understanding of the crystallization process of gradient non-uniform materials and provides guidance for the development of Fe-based NAs with high <em>B</em><sub>s</sub> and low <em>H</em><sub>c</sub>.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115108"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-17DOI: 10.1016/j.vacuum.2026.115104
Jiarong Li , Jinbo Zhai , Guozheng Zha , Wenlong Jiang , Baoqiang Xu , Dachun Liu , Bin Yang
Arsenic (As), commonly present in sulfides, oxides, and metal compounds like copper, cobalt, nickel, and lead, poses significant environmental and health hazards. Effective arsenic waste management is essential for pollution control and resource recovery. While vacuum distillation and graded condensation have been studied individually, this study introduces an integrated approach that combines single-step vacuum distillation with a multistage fractional condensation system based on molecular mean free path (MFP) principles. This method enables simultaneous recovery of elemental arsenic and enrichment of lead (Pb), bismuth (Bi), and silver (Ag) from highly toxic waste. By aligning condenser spacing with arsenic's MFP, the system enhances selective volatilization, differing from earlier empirical or single-stage designs. The approach was validated through theoretical analysis, CFD simulations, and experiments. At 500 °C and 10 Pa for 60 min, it achieved 99.1 % pure crude arsenic recovery, increased lead content from 37.55 % to 72.2 %, and reached 97.82 % arsenic removal efficiency. CFD results revealed detailed temperature and vapor flow patterns, closely matching experimental outcomes and confirming effectiveness. This clean, one-step process provides an economically feasible solution for arsenic removal and valuable metal concentration, with potential applicability to other complex waste streams.
{"title":"One-step to extract elemental arsenic from highly toxic hazardous arsenic waste","authors":"Jiarong Li , Jinbo Zhai , Guozheng Zha , Wenlong Jiang , Baoqiang Xu , Dachun Liu , Bin Yang","doi":"10.1016/j.vacuum.2026.115104","DOIUrl":"10.1016/j.vacuum.2026.115104","url":null,"abstract":"<div><div>Arsenic (As), commonly present in sulfides, oxides, and metal compounds like copper, cobalt, nickel, and lead, poses significant environmental and health hazards. Effective arsenic waste management is essential for pollution control and resource recovery. While vacuum distillation and graded condensation have been studied individually, this study introduces an integrated approach that combines single-step vacuum distillation with a multistage fractional condensation system based on molecular mean free path (MFP) principles. This method enables simultaneous recovery of elemental arsenic and enrichment of lead (Pb), bismuth (Bi), and silver (Ag) from highly toxic waste. By aligning condenser spacing with arsenic's MFP, the system enhances selective volatilization, differing from earlier empirical or single-stage designs. The approach was validated through theoretical analysis, CFD simulations, and experiments. At 500 °C and 10 Pa for 60 min, it achieved 99.1 % pure crude arsenic recovery, increased lead content from 37.55 % to 72.2 %, and reached 97.82 % arsenic removal efficiency. CFD results revealed detailed temperature and vapor flow patterns, closely matching experimental outcomes and confirming effectiveness. This clean, one-step process provides an economically feasible solution for arsenic removal and valuable metal concentration, with potential applicability to other complex waste streams.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115104"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electroadhesion exhibits exceptional environmental adaptability and precise controllability, making it highly promising for space applications such as robotic manipulators, orbital debris capture, and on-orbit satellite servicing. Nevertheless, the fundamental adhesion mechanisms under high-vacuum electron irradiation remain inadequately characterized, and the electron charging effect may adversely impact the electroadhesive force, which severely limits its implementation in extraterrestrial environment. This study employs dielectric polarization theory coupled with three-dimensional particle-in-cell (PIC) simulations to demonstrate that incident electrons deposit only in the superficial layer (≤2 μm depth) of dielectric coatings and target substrates, with negligible penetration to actuation electrodes. Such localized deposition induces minimal variations in interfacial potential (ΔV < 45 V) and electrostatic field distribution (variation <5.2 %), thereby preserving electroadhesive functionality. Experimental validation under simulated space conditions (electron energy: 10 keV) in a high-vacuum chamber (base pressure: 10−4 Pa) reveals: a) Consistent operational integrity of the electroadhesion pad (EA pad); b) Sustained adhesive force stability (>0.3 N/cm2) with minimal fluctuation (<11 %). These findings establish critical criteria for electroadhesion in space applications.
{"title":"Intact electroadhesive performance under 10 keV electron irradiation in high vacuum","authors":"Wenhe Liao , Bingrui Li , Wei Tian , Jinjun Duan , Jiaming Zhang , Yunfei Miao , Zhengwei Wang , Zichao Chen","doi":"10.1016/j.vacuum.2026.115098","DOIUrl":"10.1016/j.vacuum.2026.115098","url":null,"abstract":"<div><div>Electroadhesion exhibits exceptional environmental adaptability and precise controllability, making it highly promising for space applications such as robotic manipulators, orbital debris capture, and on-orbit satellite servicing. Nevertheless, the fundamental adhesion mechanisms under high-vacuum electron irradiation remain inadequately characterized, and the electron charging effect may adversely impact the electroadhesive force, which severely limits its implementation in extraterrestrial environment. This study employs dielectric polarization theory coupled with three-dimensional particle-in-cell (PIC) simulations to demonstrate that incident electrons deposit only in the superficial layer (≤2 μm depth) of dielectric coatings and target substrates, with negligible penetration to actuation electrodes. Such localized deposition induces minimal variations in interfacial potential (ΔV < 45 V) and electrostatic field distribution (variation <5.2 %), thereby preserving electroadhesive functionality. Experimental validation under simulated space conditions (electron energy: 10 keV) in a high-vacuum chamber (base pressure: 10<sup>−4</sup> Pa) reveals: a) Consistent operational integrity of the electroadhesion pad (EA pad); b) Sustained adhesive force stability (>0.3 N/cm<sup>2</sup>) with minimal fluctuation (<11 %). These findings establish critical criteria for electroadhesion in space applications.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115098"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-14DOI: 10.1016/j.vacuum.2026.115096
Rui Liu , Yang Li , Dongbin Jiang , Yuliang Bai , Xu Luo , Yanhui Sun
Surface peeling defects caused by inclusions are commonly observed in pickling coils of commercially pure titanium (CP-Ti) ingots, which deteriorate the surface quality of the rolled products. In this work, inclusions in the CP-Ti ingots melted by Electron Beam Cold Hearth Melting (EBCHM) and Vacuum Arc Remelting (VAR) are extracted by the electrolytic extraction, and their three-dimensional morphology, type, and size distribution are analyzed by using SEM. Moreover, the origins of the various inclusion types were also investigated. Besides, a dissolution model for titanium oxides is developed to simulate the dissolution of TiO2. The results show that most of inclusions are titanium oxides, accounting for 89 % of the total. The rest is a small amount of Al2O3, composite inclusions, and high-density inclusions containing W. Their sizes predominantly range from 80 to 300 μm. The total inclusion content measured in the VAR ingot is 51 % higher than that in the EBCHM ingot. During the dissolution of titanium oxides, the phase transformation occurs on the surface, leading to the formation of a thin layer of Ti3O5. In the EBCHM process, it takes 466s for the 500 μm TiO2 particle to be completely dissolved at 1720oC. The dissolution rate of inclusions is enhanced with the high temperature, but it remains almost constant with the size and time. Therefore, a low melting speed and high temperature process can promote the inclusion dissolution.
{"title":"Investigation of inclusions in CP-Ti ingots melted by electron beam cold hearth melting and Vacuum Arc remelting with electrolytic extraction method","authors":"Rui Liu , Yang Li , Dongbin Jiang , Yuliang Bai , Xu Luo , Yanhui Sun","doi":"10.1016/j.vacuum.2026.115096","DOIUrl":"10.1016/j.vacuum.2026.115096","url":null,"abstract":"<div><div>Surface peeling defects caused by inclusions are commonly observed in pickling coils of commercially pure titanium (CP-Ti) ingots, which deteriorate the surface quality of the rolled products. In this work, inclusions in the CP-Ti ingots melted by Electron Beam Cold Hearth Melting (EBCHM) and Vacuum Arc Remelting (VAR) are extracted by the electrolytic extraction, and their three-dimensional morphology, type, and size distribution are analyzed by using SEM. Moreover, the origins of the various inclusion types were also investigated. Besides, a dissolution model for titanium oxides is developed to simulate the dissolution of TiO<sub>2</sub>. The results show that most of inclusions are titanium oxides, accounting for 89 % of the total. The rest is a small amount of Al<sub>2</sub>O<sub>3</sub>, composite inclusions, and high-density inclusions containing W. Their sizes predominantly range from 80 to 300 μm. The total inclusion content measured in the VAR ingot is 51 % higher than that in the EBCHM ingot. During the dissolution of titanium oxides, the phase transformation occurs on the surface, leading to the formation of a thin layer of Ti<sub>3</sub>O<sub>5</sub>. In the EBCHM process, it takes 466s for the 500 μm TiO<sub>2</sub> particle to be completely dissolved at 1720<sup>o</sup>C. The dissolution rate of inclusions is enhanced with the high temperature, but it remains almost constant with the size and time. Therefore, a low melting speed and high temperature process can promote the inclusion dissolution.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115096"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nanocrystalline powders with an average particle size from 25 to 50 nm were obtained by milling of microcrystalline NbCy powder. The crystal structure, phase and chemical composition, morphology and particle size of the NbCy powders, their specific surface area and density were studied using XRD, SEM, BET, gas pycnometry, and chemical analysis for carbon and oxygen content. It was established that the NbCy powders contain a large amount of impurity oxygen, the amount of which is proportional to their specific surface area, and part of it is present in the form of amorphous Nb2O5. The effect of the average particle size of the NbCy powder, the impurities present in it, especially oxygen, and the temperature of vacuum annealing up to 1400 °C on its chemical and phase composition, average particle size and morphology, as well as density was studied. It was found that most of the oxygen contained in the powders reacts with NbCy upon heating in vacuum, forming niobium oxides. At higher temperatures, these oxides are reduced by carbon from NbCy. This process alters both the stoichiometry y and the phase composition of the powder. Heating of the nanocrystalline powders in vacuum to 1200 °C and above turns them into microcrystalline powders.
{"title":"Effect of vacuum annealing temperature and oxygen impurity content on microstructure and composition of NbCy nanocrystalline powders","authors":"Alexey Kurlov , Anna Postovalova , Larisa Buldakova , Danil Danilov","doi":"10.1016/j.vacuum.2026.115147","DOIUrl":"10.1016/j.vacuum.2026.115147","url":null,"abstract":"<div><div>Nanocrystalline powders with an average particle size from 25 to 50 nm were obtained by milling of microcrystalline NbC<sub><em>y</em></sub> powder. The crystal structure, phase and chemical composition, morphology and particle size of the NbC<sub><em>y</em></sub> powders, their specific surface area and density were studied using XRD, SEM, BET, gas pycnometry, and chemical analysis for carbon and oxygen content. It was established that the NbC<sub><em>y</em></sub> powders contain a large amount of impurity oxygen, the amount of which is proportional to their specific surface area, and part of it is present in the form of amorphous Nb<sub>2</sub>O<sub>5</sub>. The effect of the average particle size of the NbC<sub><em>y</em></sub> powder, the impurities present in it, especially oxygen, and the temperature of vacuum annealing up to 1400 °C on its chemical and phase composition, average particle size and morphology, as well as density was studied. It was found that most of the oxygen contained in the powders reacts with NbC<sub><em>y</em></sub> upon heating in vacuum, forming niobium oxides. At higher temperatures, these oxides are reduced by carbon from NbC<sub><em>y</em></sub>. This process alters both the stoichiometry <em>y</em> and the phase composition of the powder. Heating of the nanocrystalline powders in vacuum to 1200 °C and above turns them into microcrystalline powders.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115147"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-02-02DOI: 10.1016/j.vacuum.2026.115155
Lihu Wang , Siyi Yang , Shouren Wang , Baoping Wang , Qin Sun
This study investigates the SiC/Al interfacial bonding and matrix grain orientation, and elucidates the mechanism of electric field-induced friction enhancement through temperature and electrorheological effects. Extruded SiC/6092Al composites were fabricated by powder metallurgy and hot extrusion. Grain features, microstructure, physical properties, and electro-controlled friction and wear behavior were characterized. Recovered grains in the Al matrix promote the <111>∥TD texture. SiC particles are uniformly dispersed throughout the matrix without agglomeration. At the SiC/Al interface, SiC atoms conform to the XYX and X-0.5X-X distribution patterns. Precipitation of β and Q phases is observed in the Al matrix. Application of an external voltage significantly enhances the friction coefficient of the specimens. Specifically, the increments in friction coefficient for specimens J1, J2, and J3 are 0.075, 0.143, and 0.109, respectively. The friction-increasing effect of the electric field exhibits characteristics of immediacy, abruptness, and reversibility. The synergistic mechanism of temperature and electrorheological effects in electrically controlled friction enhancement is systematically explained. Furthermore, the wear mechanism of composites is analyzed. SiC reinforcement enhances wear resistance. In the absence of an electric field, the dominant wear modes are plowing and fatigue spalling; under an applied electric field, plowing and adhesive wear become the primary mechanisms.
{"title":"Microstructure analysis and electro-controlled tribological properties of extruded SiC/6092Al composites","authors":"Lihu Wang , Siyi Yang , Shouren Wang , Baoping Wang , Qin Sun","doi":"10.1016/j.vacuum.2026.115155","DOIUrl":"10.1016/j.vacuum.2026.115155","url":null,"abstract":"<div><div>This study investigates the SiC/Al interfacial bonding and matrix grain orientation, and elucidates the mechanism of electric field-induced friction enhancement through temperature and electrorheological effects. Extruded SiC/6092Al composites were fabricated by powder metallurgy and hot extrusion. Grain features, microstructure, physical properties, and electro-controlled friction and wear behavior were characterized. Recovered grains in the Al matrix promote the <111>∥TD texture. SiC particles are uniformly dispersed throughout the matrix without agglomeration. At the SiC/Al interface, SiC atoms conform to the XYX and X-0.5X-X distribution patterns. Precipitation of β and Q phases is observed in the Al matrix. Application of an external voltage significantly enhances the friction coefficient of the specimens. Specifically, the increments in friction coefficient for specimens J1, J2, and J3 are 0.075, 0.143, and 0.109, respectively. The friction-increasing effect of the electric field exhibits characteristics of immediacy, abruptness, and reversibility. The synergistic mechanism of temperature and electrorheological effects in electrically controlled friction enhancement is systematically explained. Furthermore, the wear mechanism of composites is analyzed. SiC reinforcement enhances wear resistance. In the absence of an electric field, the dominant wear modes are plowing and fatigue spalling; under an applied electric field, plowing and adhesive wear become the primary mechanisms.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115155"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-22DOI: 10.1016/j.vacuum.2026.115127
Wei-Chih Chang
Room-temperature exchange bias (EB) in Mn-based noncollinear antiferromagnets has drawn increasing attention for spintronic applications. However, in D019-Mn3Ga/CoFeB system, the EB effect is usually restricted to low temperatures. Here, we demonstrate that introducing a Ru seed layer enables a tunable and anisotropic EB at room temperature. Interfacial strain induced by the Ru layer modulates the lattice symmetry and reconfigures the Dzyaloshinskii-Moriya interaction (DMI). These strain-mediated modifications promote the formation of nanoscale ferromagnetic (FM) clusters driven by the reconfiguration of magnetic octupole symmetry and the displacement of Weyl nodes in momentum space, which act as topological interfacial pinning centers. This selectively enhances the in-plane (IP) EB field to 35.68 Oe while reducing the out-of-plane (OOP) component. The anisotropic EB can be independently controlled by adjusting the Mn3Ga thickness: the IP EB decreases with increasing thickness due to lattice relaxation, whereas the OOP EB increases, revealing distinct interfacial and bulk topological contributions related to the stabilization of the relaxed magnetic octupole state. The observed waist-shaped hysteresis loops indicate an asynchronous reversal mechanism governed by a graded pinning landscape originating from the interplay between lattice-induced DMI and Weyl node dynamics. These results establish that both the Ru seed layer and Mn3Ga thickness are effective tuning parameters for engineering room-temperature anisotropic EB effect, providing a promising route toward noncollinear antiferromagnetic MRAM and orientation-dependent spintronic devices.
{"title":"Engineering anisotropic room-temperature exchange bias in D019-Mn3Ga/CoFeB bilayer grown on Al2O3 substrates via Ru seed layer-induced interface modulation","authors":"Wei-Chih Chang","doi":"10.1016/j.vacuum.2026.115127","DOIUrl":"10.1016/j.vacuum.2026.115127","url":null,"abstract":"<div><div>Room-temperature exchange bias (EB) in Mn-based noncollinear antiferromagnets has drawn increasing attention for spintronic applications. However, in D0<sub>19</sub>-Mn<sub>3</sub>Ga/CoFeB system, the EB effect is usually restricted to low temperatures. Here, we demonstrate that introducing a Ru seed layer enables a tunable and anisotropic EB at room temperature. Interfacial strain induced by the Ru layer modulates the lattice symmetry and reconfigures the Dzyaloshinskii-Moriya interaction (DMI). These strain-mediated modifications promote the formation of nanoscale ferromagnetic (FM) clusters driven by the reconfiguration of magnetic octupole symmetry and the displacement of Weyl nodes in momentum space, which act as topological interfacial pinning centers. This selectively enhances the in-plane (IP) EB field to 35.68 Oe while reducing the out-of-plane (OOP) component. The anisotropic EB can be independently controlled by adjusting the Mn<sub>3</sub>Ga thickness: the IP EB decreases with increasing thickness due to lattice relaxation, whereas the OOP EB increases, revealing distinct interfacial and bulk topological contributions related to the stabilization of the relaxed magnetic octupole state. The observed waist-shaped hysteresis loops indicate an asynchronous reversal mechanism governed by a graded pinning landscape originating from the interplay between lattice-induced DMI and Weyl node dynamics. These results establish that both the Ru seed layer and Mn<sub>3</sub>Ga thickness are effective tuning parameters for engineering room-temperature anisotropic EB effect, providing a promising route toward noncollinear antiferromagnetic MRAM and orientation-dependent spintronic devices.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115127"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-28DOI: 10.1016/j.vacuum.2026.115141
Yue Wang , Chaofeng Sang , Jintao Wu , Nami Li , Yu Bian , Changjiang Sun , Mingzhou Zhang , Chen Zhang , Yao Peng , Chongyang Jin , Yue Tian , Dezhen Wang
Linear plasma devices (LPDs) are important experimental platforms for investigating plasma–material interactions (PMI). In PMI experiments, it has been found that applying a target bias not only effectively modifies the incident ion energy, but also induces significant changes in the electron density and electron temperature, whereby the evolution of these plasma parameters is primarily governed by plasma transport processes. However, at present, the physical process and mechanism underlying such bias-induced variations remain unclear. In this work, biasing experiments under argon plasma discharge conditions were first carried out on the MPS-LD device. For the corresponding experiments, an electric potential model was newly developed based on the BOUT++ LPD module, enabling self-consistent simulations of plasma transport under biased conditions. Numerical simulations were then performed to reproduce the experimental results and to validate the accuracy of the proposed model. Finally, by combining experimental measurements with numerical simulations, a bias-voltage scan was performed to investigate how the electron density and electron temperature vary with the bias voltage (Ubias). The results show that applying negative bias decreases the target electron density (ne,T) while increasing the target electron temperature (Te,T). In contrast, positive bias increases both ne,T and Te,T; however, at high positive bias, ne,T first reaches a maximum and subsequently decreases with further increases in Ubias. The underlying physical mechanisms are analyzed using particle flux, momentum, and energy conservation. It indicates that the applied bias regulates the parallel electric field, thereby changing ion and electron velocities, and consequently affecting the electron density. At high positive bias, the ion velocity is further influenced by ion viscosity, leading to the reversal in ne,T. Meanwhile, the enhanced parallel electric field drives stronger currents, significantly increasing ion–electron frictional work and converting the input bias power into electron energy, which raises the electron temperature. These results contribute to a deeper understanding of the effects and mechanisms of biasing on plasma transport in the MPS-LD device.
{"title":"Experimental and simulation study of target biasing effects on plasma transport in linear plasma device MPS-LD","authors":"Yue Wang , Chaofeng Sang , Jintao Wu , Nami Li , Yu Bian , Changjiang Sun , Mingzhou Zhang , Chen Zhang , Yao Peng , Chongyang Jin , Yue Tian , Dezhen Wang","doi":"10.1016/j.vacuum.2026.115141","DOIUrl":"10.1016/j.vacuum.2026.115141","url":null,"abstract":"<div><div>Linear plasma devices (LPDs) are important experimental platforms for investigating plasma–material interactions (PMI). In PMI experiments, it has been found that applying a target bias not only effectively modifies the incident ion energy, but also induces significant changes in the electron density and electron temperature, whereby the evolution of these plasma parameters is primarily governed by plasma transport processes. However, at present, the physical process and mechanism underlying such bias-induced variations remain unclear. In this work, biasing experiments under argon plasma discharge conditions were first carried out on the MPS-LD device. For the corresponding experiments, an electric potential model was newly developed based on the BOUT++ LPD module, enabling self-consistent simulations of plasma transport under biased conditions. Numerical simulations were then performed to reproduce the experimental results and to validate the accuracy of the proposed model. Finally, by combining experimental measurements with numerical simulations, a bias-voltage scan was performed to investigate how the electron density and electron temperature vary with the bias voltage (<em>U</em><sub><em>bias</em></sub>). The results show that applying negative bias decreases the target electron density (<em>n</em><sub><em>e,T</em></sub>) while increasing the target electron temperature (<em>T</em><sub><em>e,T</em></sub>). In contrast, positive bias increases both <em>n</em><sub><em>e,T</em></sub> and <em>T</em><sub><em>e,T</em></sub>; however, at high positive bias, <em>n</em><sub><em>e,T</em></sub> first reaches a maximum and subsequently decreases with further increases in <em>U</em><sub><em>bias</em></sub>. The underlying physical mechanisms are analyzed using particle flux, momentum, and energy conservation. It indicates that the applied bias regulates the parallel electric field, thereby changing ion and electron velocities, and consequently affecting the electron density. At high positive bias, the ion velocity is further influenced by ion viscosity, leading to the reversal in <em>n</em><sub><em>e,T</em></sub>. Meanwhile, the enhanced parallel electric field drives stronger currents, significantly increasing ion–electron frictional work and converting the input bias power into electron energy, which raises the electron temperature. These results contribute to a deeper understanding of the effects and mechanisms of biasing on plasma transport in the MPS-LD device.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115141"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-02-09DOI: 10.1016/j.vacuum.2026.115168
Wen-Rui Li , Hao-Yan Liu , Guang-Yu Sun , Yu-Cheng Zhang , Chang-Chun Qi , Xiao-Gang Qin , Bai-Peng Song , Guan-Jun Zhang
In vacuum-dielectric insulation systems, the interface where dielectric is in contact with vacuum is a weak point of insulation, and the frequent occurrence of surface flashover poses a threat to the safe operation of the system. This study proposes a novel approach to mitigate flashover by constructing micron-scale pores on polyimide (PI) surfaces, fabricating films with surface pore diameters of 3.8 ± 0.9 μm, 6.0 ± 1.3 μm, 9.8 ± 2.8 μm, and 11.0 ± 3.6 μm. Experimental results demonstrate PI films with surface micron pores exhibit significantly improved flashover thresholds and a notable reduction in secondary electron yield (SEY). When the pore diameter is 11.0 ± 3.6 μm, the DC and impulse flashover thresholds increase by up to ∼79% and ∼187%, respectively, while the maximum SEY (δmax) decreases to 1.32. Particle-in-cell (PIC) simulations further validate the inhibitory effect on multipactor. It is observed that electrons are guided into pores during movement and ultimately trapped, significantly slowing down the electron avalanche development, reducing the rate of increase in average surface charge density. The electric field configuration within the pores and pore geometry facilitates the capture of electrons. This study provides an in-depth understanding of the mechanism by which surface micron-scale pores suppress multipactor and alleviate flashover, offering valuable guidance for addressing flashover problems.
{"title":"Polyimide films featuring surface micron-scale pores for superior multipactor inhibition","authors":"Wen-Rui Li , Hao-Yan Liu , Guang-Yu Sun , Yu-Cheng Zhang , Chang-Chun Qi , Xiao-Gang Qin , Bai-Peng Song , Guan-Jun Zhang","doi":"10.1016/j.vacuum.2026.115168","DOIUrl":"10.1016/j.vacuum.2026.115168","url":null,"abstract":"<div><div>In vacuum-dielectric insulation systems, the interface where dielectric is in contact with vacuum is a weak point of insulation, and the frequent occurrence of surface flashover poses a threat to the safe operation of the system. This study proposes a novel approach to mitigate flashover by constructing micron-scale pores on polyimide (PI) surfaces, fabricating films with surface pore diameters of 3.8 ± 0.9 μm, 6.0 ± 1.3 μm, 9.8 ± 2.8 μm, and 11.0 ± 3.6 μm. Experimental results demonstrate PI films with surface micron pores exhibit significantly improved flashover thresholds and a notable reduction in secondary electron yield (SEY). When the pore diameter is 11.0 ± 3.6 μm, the DC and impulse flashover thresholds increase by up to ∼79% and ∼187%, respectively, while the maximum SEY (<em>δ</em><sub><em>max</em></sub>) decreases to 1.32. Particle-in-cell (PIC) simulations further validate the inhibitory effect on multipactor. It is observed that electrons are guided into pores during movement and ultimately trapped, significantly slowing down the electron avalanche development, reducing the rate of increase in average surface charge density. The electric field configuration within the pores and pore geometry facilitates the capture of electrons. This study provides an in-depth understanding of the mechanism by which surface micron-scale pores suppress multipactor and alleviate flashover, offering valuable guidance for addressing flashover problems.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115168"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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