The dielectric strength of high-voltage vacuum gaps is a critical issue in the development and operation of high-power electrophysical devices. It is well known that the onset of a significant field-emission current from the vacuum gap cathode precedes vacuum breakdown. In this study, we investigate the correlation between the static vacuum breakdown voltage and the cathode's field emission properties. We examined a pure copper cathode with dimensions on the order of tens of micrometers. A series of sequential field-emission current-voltage measurements and vacuum breakdown tests were conducted. Additionally, the field-emission orthodoxy factor was calculated. For different cathode surface states, we obtained sets of local electric field enhancement factors, β, emission orthodoxy factors, and breakdown voltages. Assuming a specific breakdown electric field strength and using the determined β values, we estimated breakdown voltage values and compared these with experimentally measured ones. Our analysis revealed that within a particular range of the field-emission orthodoxy factor, the corresponding β values allowed the estimation of the breakdown voltage with approximately 10 % error. These results suggest that it is possible to develop an approach for predicting static vacuum breakdown voltage based solely on the field emission properties of the cathode.
{"title":"The dependence of vacuum gap breakdown voltage on field emission properties","authors":"S.A. Barengolts , Yu.I. Mamontov , I.V. Uimanov , Yu.A. Zemskov","doi":"10.1016/j.vacuum.2026.115107","DOIUrl":"10.1016/j.vacuum.2026.115107","url":null,"abstract":"<div><div>The dielectric strength of high-voltage vacuum gaps is a critical issue in the development and operation of high-power electrophysical devices. It is well known that the onset of a significant field-emission current from the vacuum gap cathode precedes vacuum breakdown. In this study, we investigate the correlation between the static vacuum breakdown voltage and the cathode's field emission properties. We examined a pure copper cathode with dimensions on the order of tens of micrometers. A series of sequential field-emission current-voltage measurements and vacuum breakdown tests were conducted. Additionally, the field-emission orthodoxy factor was calculated. For different cathode surface states, we obtained sets of local electric field enhancement factors, <em>β</em>, emission orthodoxy factors, and breakdown voltages. Assuming a specific breakdown electric field strength and using the determined <em>β</em> values, we estimated breakdown voltage values and compared these with experimentally measured ones. Our analysis revealed that within a particular range of the field-emission orthodoxy factor, the corresponding <em>β</em> values allowed the estimation of the breakdown voltage with approximately 10 % error. These results suggest that it is possible to develop an approach for predicting static vacuum breakdown voltage based solely on the field emission properties of the cathode.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115107"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080121","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: 2026-01-20DOI: 10.1016/j.vacuum.2026.115116
Yuhang Chen , Jie Li , Chao Pan , Ruili Ma , Jidong Long , Xiaozhong He , Jinshui Shi , Kefu Liu
High-power, compact, built-in Penning negative hydrogen ion source has been widely used in particle accelerator applications. But the problem of its short operating life has been an issue, with cathode mass loss being the main factor affecting its life. The material lost from the cathode will condense on the anode wall and will flake off under alternating heat and cold. The flaking material is directed from the cathode to the anode under the action of an electric field, and when the debris is too large it will short-circuit the cathode and anode directly. To solve this key problem, it is necessary to study the specific causes of cathode mass loss, and optimize the operation methods and design ideas of the ion source through these causes. In this paper, the cathode mass loss mechanism was investigated. It is considered that the cathode mass of this ion source is mainly lost through the evaporation process during the large arc current operation under the high purity gas environment. And several optimization measures are proposed in the operation and design of the equipment.
{"title":"Study on the principle of mass loss of Penning Negative ion source cathode","authors":"Yuhang Chen , Jie Li , Chao Pan , Ruili Ma , Jidong Long , Xiaozhong He , Jinshui Shi , Kefu Liu","doi":"10.1016/j.vacuum.2026.115116","DOIUrl":"10.1016/j.vacuum.2026.115116","url":null,"abstract":"<div><div>High-power, compact, built-in Penning negative hydrogen ion source has been widely used in particle accelerator applications. But the problem of its short operating life has been an issue, with cathode mass loss being the main factor affecting its life. The material lost from the cathode will condense on the anode wall and will flake off under alternating heat and cold. The flaking material is directed from the cathode to the anode under the action of an electric field, and when the debris is too large it will short-circuit the cathode and anode directly. To solve this key problem, it is necessary to study the specific causes of cathode mass loss, and optimize the operation methods and design ideas of the ion source through these causes. In this paper, the cathode mass loss mechanism was investigated. It is considered that the cathode mass of this ion source is mainly lost through the evaporation process during the large arc current operation under the high purity gas environment. And several optimization measures are proposed in the operation and design of the equipment.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115116"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080216","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: 2026-01-13DOI: 10.1016/j.vacuum.2026.115093
Qingyun Li , Haibo Sun , Guoyong Zhao , Yanjie Li , Shuo Yu , Jingyao Bian
The internal flow characteristics and hydraulic performance of water ring vacuum pumps are significantly affected by the impeller and casing profiles. To reduce energy losses and improve suction performance and efficiency, a multi-objective co-optimization of the impeller and casing profiles of a water ring vacuum pump is conducted by integrating experimental measurements with numerical simulations. First, a theoretical model of hydraulic losses in water ring vacuum pumps is established based on entropy production theory, revealing the underlying mechanisms of these losses. Subsequently, the flow fields and overall performance before and after optimization are compared through integrated suction-performance analysis. The effects of profile parameters on suction capacity and hydraulic losses are thereby revealed, providing a theoretical basis for the structural optimization of water ring vacuum pumps. Results indicate that, in the optimization model targeting minimal wall effect entropy production, the wall effect entropy production decreases by 15.14 %, accompanied by a 0.47 % improvement in isothermal compression efficiency. In the optimization model targeting maximum suction capacity, the suction capacity increases by 17.83 %, and the isothermal compression efficiency improves by 4.16 %.
{"title":"Co-optimization and performance investigation of water ring vacuum pump impeller and casing profiles based on entropy production theory","authors":"Qingyun Li , Haibo Sun , Guoyong Zhao , Yanjie Li , Shuo Yu , Jingyao Bian","doi":"10.1016/j.vacuum.2026.115093","DOIUrl":"10.1016/j.vacuum.2026.115093","url":null,"abstract":"<div><div>The internal flow characteristics and hydraulic performance of water ring vacuum pumps are significantly affected by the impeller and casing profiles. To reduce energy losses and improve suction performance and efficiency, a multi-objective co-optimization of the impeller and casing profiles of a water ring vacuum pump is conducted by integrating experimental measurements with numerical simulations. First, a theoretical model of hydraulic losses in water ring vacuum pumps is established based on entropy production theory, revealing the underlying mechanisms of these losses. Subsequently, the flow fields and overall performance before and after optimization are compared through integrated suction-performance analysis. The effects of profile parameters on suction capacity and hydraulic losses are thereby revealed, providing a theoretical basis for the structural optimization of water ring vacuum pumps. Results indicate that, in the optimization model targeting minimal wall effect entropy production, the wall effect entropy production decreases by 15.14 %, accompanied by a 0.47 % improvement in isothermal compression efficiency. In the optimization model targeting maximum suction capacity, the suction capacity increases by 17.83 %, and the isothermal compression efficiency improves by 4.16 %.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115093"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145993596","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: 2026-01-15DOI: 10.1016/j.vacuum.2026.115095
Zijian Liu , Zijie Li , Zhihao Liu , Yong Wang , Rui Ding , Dezhi Sun , Chao Song , Yongjie Ding
The rapid deployment of commercial mega-constellations has created an urgent demand for electric propulsion systems that combine lightweight design with high power density. Although permanent magnet Hall thrusters have become one of the main practical solutions, they face a critical thermal-magnetic conflict: increasing power density exacerbates heat accumulation, leading to irreversible demagnetization due to the intrinsic thermal sensitivity of the permanent magnets. To address this fundamental challenge, this paper proposes a novel thermal management architecture based on the HEP-1350PM V2 thruster as the platform. The design replaces traditional structures with a lightweight 7075 aluminum alloy frame and integrates a black anodized radiator to form a low-thermal-resistance conduction path, significantly enhancing heat conduction and radiation capabilities. This approach effectively overcomes thermal bottlenecks, enabling stable operation under high thermal loads. Experimental results demonstrate that the thruster can reach thermal equilibrium across a wide power range from 200 W to 2 kW. Its peak total efficiency reaches 63.3 % with xenon propellant and 50.2 % with krypton propellant, while its power-to-weight ratio reaches 1.11 kW/kg, three times that of the SPT-100 thruster.
This study validates the effectiveness of the proposed architecture, providing a thermal management strategy for future high-power, lightweight space propulsion systems.
{"title":"Design and performance of a lightweight, high power density permanent magnet Hall thruster","authors":"Zijian Liu , Zijie Li , Zhihao Liu , Yong Wang , Rui Ding , Dezhi Sun , Chao Song , Yongjie Ding","doi":"10.1016/j.vacuum.2026.115095","DOIUrl":"10.1016/j.vacuum.2026.115095","url":null,"abstract":"<div><div>The rapid deployment of commercial mega-constellations has created an urgent demand for electric propulsion systems that combine lightweight design with high power density. Although permanent magnet Hall thrusters have become one of the main practical solutions, they face a critical thermal-magnetic conflict: increasing power density exacerbates heat accumulation, leading to irreversible demagnetization due to the intrinsic thermal sensitivity of the permanent magnets. To address this fundamental challenge, this paper proposes a novel thermal management architecture based on the HEP-1350PM V2 thruster as the platform. The design replaces traditional structures with a lightweight 7075 aluminum alloy frame and integrates a black anodized radiator to form a low-thermal-resistance conduction path, significantly enhancing heat conduction and radiation capabilities. This approach effectively overcomes thermal bottlenecks, enabling stable operation under high thermal loads. Experimental results demonstrate that the thruster can reach thermal equilibrium across a wide power range from 200 W to 2 kW. Its peak total efficiency reaches 63.3 % with xenon propellant and 50.2 % with krypton propellant, while its power-to-weight ratio reaches 1.11 kW/kg, three times that of the SPT-100 thruster.</div><div>This study validates the effectiveness of the proposed architecture, providing a thermal management strategy for future high-power, lightweight space propulsion systems.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115095"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026011","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}
This study presents a water vapor-assisted solid-state sintering strategy to fabricate CsPbI3@SiO2 perovskite composites. Through high humidity and temperature, CsPbI3 nanocrystals are efficiently encapsulated within a SiO2 matrix, resulting in dramatically enhanced stability. The composite retains over 85 % of its initial luminescence after 360 days in ambient conditions and demonstrates excellent resistance to polar solvents and acids. Due to its high stability, the composite exhibits promising performance in white light-emitting diodes (WLEDs) and information encryption applications, providing a viable pathway toward practical perovskite-based devices.
{"title":"Vapor-assisted solid-state sintering of CsPbI3@SiO2 core-shell nanocrystals for enhanced environmental stability","authors":"Longxun Teng, Xin Li, Yuanxin Chunyu, Jiaxiang Liang, Xinyue Shao, Haiqing Sun, Xiaoyuan Zhan, Weiwei Zhang, Rui Liu, Jianxu Ding, Huiling Zhu","doi":"10.1016/j.vacuum.2026.115139","DOIUrl":"10.1016/j.vacuum.2026.115139","url":null,"abstract":"<div><div>This study presents a water vapor-assisted solid-state sintering strategy to fabricate CsPbI<sub>3</sub>@SiO<sub>2</sub> perovskite composites. Through high humidity and temperature, CsPbI<sub>3</sub> nanocrystals are efficiently encapsulated within a SiO<sub>2</sub> matrix, resulting in dramatically enhanced stability. The composite retains over 85 % of its initial luminescence after 360 days in ambient conditions and demonstrates excellent resistance to polar solvents and acids. Due to its high stability, the composite exhibits promising performance in white light-emitting diodes (WLEDs) and information encryption applications, providing a viable pathway toward practical perovskite-based devices.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115139"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080119","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.2026.115135
Jinyin Fu , Libo Zhou , Zhou Li , Cong Li , Minbo Wang , Jian Chen
In this study, Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloy was fabricated using laser powder bed fusion. By analyzing the printing quality and mechanical properties of TC11 alloy printed under different process parameters, an optimum processing window (laser power of 200 W, laser scanning speed of 1100 mm/s) was identified. Under the optimal process parameters, the sample achieved a relative density of 99.6 % and excellent mechanical properties (Ultimate Tensile Strength of 1331 ± 11 MPa, Yield Strength of 1004 ± 13 MPa and Elongation of 12.1 ± 1.2 %). After heat-treated at 900 °C, the sample exhibited an equiaxed α phase and thin film β phase with the elongation increasing by approximately 39.3 % (from 12.1 ± 1.2 % to 16.8 ± 0.6 %), while the yield strength (996 ± 1 MPa) remained at the as-built level. The enhanced ductility of the heat-treated sample is attributed to three key factors: the decreased low-angle grain boundaries which minimizes stress concentration during deformation, the reduced α′ martensite with thin-film β-phase formation (coordinating plastic flow via a ductile phase), and the improved α-β crystallographic coincidence with reduced lattice distortion, lowering interfacial stress and promoting slip transmission.
{"title":"Microstructure and mechanical properties of titanium alloy via laser powder bed fusion and heat treatment","authors":"Jinyin Fu , Libo Zhou , Zhou Li , Cong Li , Minbo Wang , Jian Chen","doi":"10.1016/j.vacuum.2026.115135","DOIUrl":"10.1016/j.vacuum.2026.115135","url":null,"abstract":"<div><div>In this study, Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloy was fabricated using laser powder bed fusion. By analyzing the printing quality and mechanical properties of TC11 alloy printed under different process parameters, an optimum processing window (laser power of 200 W, laser scanning speed of 1100 mm/s) was identified. Under the optimal process parameters, the sample achieved a relative density of 99.6 % and excellent mechanical properties (Ultimate Tensile Strength of 1331 ± 11 MPa, Yield Strength of 1004 ± 13 MPa and Elongation of 12.1 ± 1.2 %). After heat-treated at 900 °C, the sample exhibited an equiaxed α phase and thin film β phase with the elongation increasing by approximately 39.3 % (from 12.1 ± 1.2 % to 16.8 ± 0.6 %), while the yield strength (996 ± 1 MPa) remained at the as-built level. The enhanced ductility of the heat-treated sample is attributed to three key factors: the decreased low-angle grain boundaries which minimizes stress concentration during deformation, the reduced α′ martensite with thin-film β-phase formation (coordinating plastic flow via a ductile phase), and the improved α-β crystallographic coincidence with reduced lattice distortion, lowering interfacial stress and promoting slip transmission.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115135"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080122","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}
High Entropy alloys (HEAs) have recently emerged as promising candidates for thermoelectric applications due to their tunable transport properties enabled by entropy engineering. In this work, we investigate the effect of entropy engineering on the thermal and electrical transport properties of CoCrFeNi system through Ag alloying. The CoCrFeNiAg0.2 alloy exhibited a low lattice thermal conductivity of ∼1.34 Wm−1K−1 at 700 K, which is ∼8.6 times lower than that of the parent alloy, attributed to severe lattice distortions induced by mass and size disorder. All the HEA compositions displayed rare p-type conduction. Notably, the CoCrFeNiAg0.1 showed the highest Seebeck coefficient of ∼17.5 μVK−1, representing a 44.6 % enhancement over the reference alloy, along with the highest power factor of 213 μWm−1K−2 at 700 K. These results demonstrate that entropy-driven atomic disorder is an effective strategy to suppress phonon transport and enhance the thermoelectric performance in metallic HEAs.
{"title":"Entropy engineered p-type Ag-alloyed CoCrFeNi metallic high entropy alloys with low lattice thermal conductivity","authors":"K. Arun , Kowsalya Senthil Kumar , Navaneethan Mani , Senthil Kumar Eswaran","doi":"10.1016/j.vacuum.2026.115130","DOIUrl":"10.1016/j.vacuum.2026.115130","url":null,"abstract":"<div><div>High Entropy alloys (HEAs) have recently emerged as promising candidates for thermoelectric applications due to their tunable transport properties enabled by entropy engineering. In this work, we investigate the effect of entropy engineering on the thermal and electrical transport properties of CoCrFeNi system through Ag alloying. The CoCrFeNiAg<sub>0.2</sub> alloy exhibited a low lattice thermal conductivity of ∼1.34 Wm<sup>−1</sup>K<sup>−1</sup> at 700 K, which is ∼8.6 times lower than that of the parent alloy, attributed to severe lattice distortions induced by mass and size disorder. All the HEA compositions displayed rare <em>p</em>-type conduction. Notably, the CoCrFeNiAg<sub>0.1</sub> showed the highest Seebeck coefficient of ∼17.5 μVK<sup>−1</sup>, representing a 44.6 % enhancement over the reference alloy, along with the highest power factor of 213 μWm<sup>−1</sup>K<sup>−2</sup> at 700 K. These results demonstrate that entropy-driven atomic disorder is an effective strategy to suppress phonon transport and enhance the thermoelectric performance in metallic HEAs.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115130"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080123","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: 2026-02-10DOI: 10.1016/j.vacuum.2026.115172
Qi Cao , Na Zhao , Tianyi Yang , Zhengjin Zhang , Long Cheng , Dejing Zhou , Hui Liu
To meet the multi-functional requirements of aluminum alloys for liquid cooling plates in new energy vehicles, including high strength, excellent corrosion resistance, and good brazability, a novel 4045/1050MOD/6xxx/1050MOD four-layer cladding aluminum alloy was designed and fabricated. The microstructural evolution, mechanical properties, and corrosion behavior in SWAAT salt spray environment were systematically investigated after brazing (600 °C × 10 min) followed by various artificial and natural aging treatments. Results demonstrate that specimens subjected to post-brazing artificial aging at 200 °C for 2 h achieved ultimate tensile strength and yield strength of 252 MPa and 214 MPa, respectively, representing increases of 150% and 330% compared to the O-temper condition, and significantly superior performance to natural aging and traditional 3xxx series cladding aluminum alloys. Microstructural analysis revealed that the 1050MOD interlayer effectively suppressed the diffusion of Mg towards the surface, and its coarse and elongated grain structure helped mitigate the tendency for melting erosion induced by the inward diffusion of Si. After 56 days of SWAAT salt spray testing, the corrosion depth ratio was only 41.7%. The interlayer, acting as a sacrificial anode, exhibited typical laminar corrosion characteristics, effectively retarding the inward propagation of pitting corrosion towards the core material. This study provides a theoretical basis and structural design reference for the application of high-strength, high-corrosion-resistant multi-layer cladding aluminum alloys in the thermal management systems of new energy vehicles.
{"title":"Synergistic strengthening by brazing-aging and corrosion behavior of a high-strength corrosion-resistant four-layer cladding aluminum alloy","authors":"Qi Cao , Na Zhao , Tianyi Yang , Zhengjin Zhang , Long Cheng , Dejing Zhou , Hui Liu","doi":"10.1016/j.vacuum.2026.115172","DOIUrl":"10.1016/j.vacuum.2026.115172","url":null,"abstract":"<div><div>To meet the multi-functional requirements of aluminum alloys for liquid cooling plates in new energy vehicles, including high strength, excellent corrosion resistance, and good brazability, a novel 4045/1050MOD/6xxx/1050MOD four-layer cladding aluminum alloy was designed and fabricated. The microstructural evolution, mechanical properties, and corrosion behavior in SWAAT salt spray environment were systematically investigated after brazing (600 °C × 10 min) followed by various artificial and natural aging treatments. Results demonstrate that specimens subjected to post-brazing artificial aging at 200 °C for 2 h achieved ultimate tensile strength and yield strength of 252 MPa and 214 MPa, respectively, representing increases of 150% and 330% compared to the O-temper condition, and significantly superior performance to natural aging and traditional 3xxx series cladding aluminum alloys. Microstructural analysis revealed that the 1050MOD interlayer effectively suppressed the diffusion of Mg towards the surface, and its coarse and elongated grain structure helped mitigate the tendency for melting erosion induced by the inward diffusion of Si. After 56 days of SWAAT salt spray testing, the corrosion depth ratio was only 41.7%. The interlayer, acting as a sacrificial anode, exhibited typical laminar corrosion characteristics, effectively retarding the inward propagation of pitting corrosion towards the core material. This study provides a theoretical basis and structural design reference for the application of high-strength, high-corrosion-resistant multi-layer cladding aluminum alloys in the thermal management systems of new energy vehicles.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115172"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174068","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}
A novel intersecting-axis meshing Quimby-tooth dry screw vacuum pump was proposed in this paper. The mathematical model for generating the geometric structure of intersecting-axis meshing Quimby-tooth screw rotors is established, alongside a geometric characteristic calculation model for this novel screw structure. Two basic design methods for the intersecting-axis meshing Quimby-tooth screw structure are proposed, and their geometric characteristics are analyzed by comparing them with conventional parallel-axis meshing screw rotors, thus revealing the technical potential of this new technology. The proposed geometry generation model is verified by fabricating a prototype of the intersecting-axis meshing screw vacuum pump via 3D printing, while the geometric characteristic analysis model is validated using commercial software. Research results show that intersecting-axis meshing technology can reduce rotor volume by 24 %, leakage channel length by 32 %, and gear meshing velocity by 44.5 %. This study provides fundamental references and insights for the development of next-generation dry screw vacuum pumps, further advancing progress in vacuum acquisition fields.
{"title":"Design of a novel intersecting-axis meshing Quimby-tooth dry screw vacuum pump","authors":"Dantong Li, Xiaoqian Chen, Kai Ma, Chongzhou Sun, Zhilong He, Chuang Wang, Ziwen Xing","doi":"10.1016/j.vacuum.2026.115121","DOIUrl":"10.1016/j.vacuum.2026.115121","url":null,"abstract":"<div><div>A novel intersecting-axis meshing Quimby-tooth dry screw vacuum pump was proposed in this paper. The mathematical model for generating the geometric structure of intersecting-axis meshing Quimby-tooth screw rotors is established, alongside a geometric characteristic calculation model for this novel screw structure. Two basic design methods for the intersecting-axis meshing Quimby-tooth screw structure are proposed, and their geometric characteristics are analyzed by comparing them with conventional parallel-axis meshing screw rotors, thus revealing the technical potential of this new technology. The proposed geometry generation model is verified by fabricating a prototype of the intersecting-axis meshing screw vacuum pump via 3D printing, while the geometric characteristic analysis model is validated using commercial software. Research results show that intersecting-axis meshing technology can reduce rotor volume by 24 %, leakage channel length by 32 %, and gear meshing velocity by 44.5 %. This study provides fundamental references and insights for the development of next-generation dry screw vacuum pumps, further advancing progress in vacuum acquisition fields.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115121"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174104","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: 2026-01-31DOI: 10.1016/j.vacuum.2026.115152
Dianguo Ma , Xiaojun Zhang , Meng Wang , Wei Zhang , Yingmin Wang , Zhenya Song , Xiaogang You , Zhiqiang Song , Zhongkai Guo , Mingji Zong , Yanli Zhu , Lincai Zhang
A hard magnetic high-entropy alloy (HEA) Fe35Co20Ni5Pt15B25 was designed and prepared by a two-step process of melt-spinning and subsequent annealing in high vacuum conditions. A nanocomposite structure consisting of amorphous and fcc-(Fe, Co, Ni)Pt phases was obtained in as-quenched alloy, while a composite structure composing of nanoscaled L10-(Fe, Co, Ni)Pt and (Fe, Co, Ni)2B phases was created after an appropriate vacuum annealing. The annealed HEA exhibited hard magnetic properties. The coercivity (iHc), saturation magnetizations (Bs), remanence ratio (Mr/Ms), and the maximum energy product ((BH)max) of the annealed Fe35Co20Ni5Pt15B25 high-entropy alloy were in the ranges of 207.7–996.6 kA/m, 0.50–0.77 T, 0.64–0.70, and 18.3–21.7 kJ/m3, respectively. When the annealing temperature was increased, iHc firstly increased to a maximum value of 996.6 kA/m, and then decrease. The good hard magnetic property is due to the formation of homogeneous nanocomposite structure in the annealed HEA, leading to exchange couplings among the nano-sized hard L10-(Fe, Co, Ni)Pt and soft (Fe, Co, Ni)2B magnetic phases.
{"title":"Composition design and hard magnetic properties of high-entropy alloys","authors":"Dianguo Ma , Xiaojun Zhang , Meng Wang , Wei Zhang , Yingmin Wang , Zhenya Song , Xiaogang You , Zhiqiang Song , Zhongkai Guo , Mingji Zong , Yanli Zhu , Lincai Zhang","doi":"10.1016/j.vacuum.2026.115152","DOIUrl":"10.1016/j.vacuum.2026.115152","url":null,"abstract":"<div><div>A hard magnetic high-entropy alloy (HEA) Fe<sub>35</sub>Co<sub>20</sub>Ni<sub>5</sub>Pt<sub>15</sub>B<sub>25</sub> was designed and prepared by a two-step process of melt-spinning and subsequent annealing in high vacuum conditions. A nanocomposite structure consisting of amorphous and fcc-(Fe, Co, Ni)Pt phases was obtained in as-quenched alloy, while a composite structure composing of nanoscaled <em>L</em>1<sub>0</sub>-(Fe, Co, Ni)Pt and (Fe, Co, Ni)<sub>2</sub>B phases was created after an appropriate vacuum annealing. The annealed HEA exhibited hard magnetic properties. The coercivity (<sub>i</sub><em>H</em><sub>c</sub>), saturation magnetizations (<em>B</em><sub>s</sub>), remanence ratio (<em>M</em><sub>r</sub><em>/M</em><sub>s</sub>), and the maximum energy product ((<em>BH</em>)<sub>max</sub>) of the annealed Fe<sub>35</sub>Co<sub>20</sub>Ni<sub>5</sub>Pt<sub>15</sub>B<sub>25</sub> high-entropy alloy were in the ranges of 207.7–996.6 kA/m, 0.50–0.77 T, 0.64–0.70, and 18.3–21.7 kJ/m<sup>3</sup>, respectively. When the annealing temperature was increased, <sub>i</sub><em>H</em><sub>c</sub> firstly increased to a maximum value of 996.6 kA/m, and then decrease. The good hard magnetic property is due to the formation of homogeneous nanocomposite structure in the annealed HEA, leading to exchange couplings among the nano-sized hard <em>L</em>1<sub>0</sub>-(Fe, Co, Ni)Pt and soft (Fe, Co, Ni)<sub>2</sub>B magnetic phases.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115152"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174101","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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