This study proposes a novel rejuvenation heat treatment (RHT) strategy designed to preserve grain-boundary M23C6 carbides, aiming to regenerate the creep performance of long-term serviced directionally solidified turbine blades. Microstructural characterization reveals section-dependent degradation mechanisms: while the root section mainly exhibits dislocation networks, the airfoil suffers from severe secondary γ′ coarsening, stacking fault shearing, and MC carbide decomposition into brittle η phase. The applied RHT successfully eliminates the deleterious η phase, dissolves coarsened γ′, and refines the strengthening precipitates from 1 μm to 0.35 μm, thereby restoring the alloy's ability to form regular interfacial rafts under stress. Consequently, post-recovery heat treatment yields about 100 % increase in creep life at both blade airfoil and root sections. However, it is found that irreversible Cr-enrichment at airfoil grain boundaries induces spheroidal M23C6 carbides, which accelerates failure. These findings elucidate the microstructural limits of rejuvenation and offer a pathway for optimizing life-extension strategies for critical turbine components.
{"title":"The effect of an innovative rejuvenation heat treatment on the microstructure and creep performance of DS-GTD 111 superalloy","authors":"Lijie Qiao , Yunpeng Fan , Xinbao Zhao , Mingyang Yu , Yu Zhou , Yuan Cheng , Quanzhao Yue , Wanshun Xia , Yuefeng Gu , Ze Zhang","doi":"10.1016/j.vacuum.2025.115056","DOIUrl":"10.1016/j.vacuum.2025.115056","url":null,"abstract":"<div><div>This study proposes a novel rejuvenation heat treatment (RHT) strategy designed to preserve grain-boundary M<sub>23</sub>C<sub>6</sub> carbides, aiming to regenerate the creep performance of long-term serviced directionally solidified turbine blades. Microstructural characterization reveals section-dependent degradation mechanisms: while the root section mainly exhibits dislocation networks, the airfoil suffers from severe secondary γ′ coarsening, stacking fault shearing, and MC carbide decomposition into brittle η phase. The applied RHT successfully eliminates the deleterious η phase, dissolves coarsened γ′, and refines the strengthening precipitates from 1 μm to 0.35 μm, thereby restoring the alloy's ability to form regular interfacial rafts under stress. Consequently, post-recovery heat treatment yields about 100 % increase in creep life at both blade airfoil and root sections. However, it is found that irreversible Cr-enrichment at airfoil grain boundaries induces spheroidal M<sub>23</sub>C<sub>6</sub> carbides, which accelerates failure. These findings elucidate the microstructural limits of rejuvenation and offer a pathway for optimizing life-extension strategies for critical turbine components.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115056"},"PeriodicalIF":3.9,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977736","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 : 2026-01-10DOI: 10.1016/j.vacuum.2026.115081
Chang Liu, Shuangyuan Wang
A series of Mo/W composite thin films with surface-enhanced Raman scattering was obtained using laser modification technology at room temperature. The enhancement was due to the introduction of oxygen vacancy defects that effectively enhanced the charge transfer efficiency between the probe molecules and the composite thin film. Laser treatment induced the formation of nanoparticles on the sample surface, which significantly strengthened the nanogaps and resulted in more “hot spots,” ultimately leading to a remarkable enhancement of the localized electric field. The dual mechanisms of chemical enhancement and electromagnetic enhancement collectively determined the intensity of the Raman scattering signals. The processed Mo/W films exhibited excellent homogeneity and reproducibility in surface-enhanced Raman spectroscopy tests with a detection limit of 10−7 mol/L for methylene blue dye and an enhancement factor of 3.3 × 104. The simulation results that were obtained via the finite-difference time-domain method showed substantial agreement with the experimental results.
{"title":"Laser induced the surface enhanced Raman scattering in W-Mo composite thin film","authors":"Chang Liu, Shuangyuan Wang","doi":"10.1016/j.vacuum.2026.115081","DOIUrl":"10.1016/j.vacuum.2026.115081","url":null,"abstract":"<div><div>A series of Mo/W composite thin films with surface-enhanced Raman scattering was obtained using laser modification technology at room temperature. The enhancement was due to the introduction of oxygen vacancy defects that effectively enhanced the charge transfer efficiency between the probe molecules and the composite thin film. Laser treatment induced the formation of nanoparticles on the sample surface, which significantly strengthened the nanogaps and resulted in more “hot spots,” ultimately leading to a remarkable enhancement of the localized electric field. The dual mechanisms of chemical enhancement and electromagnetic enhancement collectively determined the intensity of the Raman scattering signals. The processed Mo/W films exhibited excellent homogeneity and reproducibility in surface-enhanced Raman spectroscopy tests with a detection limit of 10<sup>−7</sup> mol/L for methylene blue dye and an enhancement factor of 3.3 × 10<sup>4</sup>. The simulation results that were obtained via the finite-difference time-domain method showed substantial agreement with the experimental results.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115081"},"PeriodicalIF":3.9,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977737","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 : 2026-01-10DOI: 10.1016/j.vacuum.2026.115085
Jitendar Kumar Tiwari , Bala Malladi , Tatiana Mishurova , Tobias Fritsch , Lars Nyborg , Yu Cao
Surface roughness strongly influences the performance of fine internal channels in additively manufactured components. This study investigates how contour process parameters affect the surface finish of 1 mm-diameter channels produced by powder bed fusion–laser beam (PBF-LB). Five contour parameter sets with progressively increasing laser energy density (LED) were applied, while keeping infill parameters constant. Surface roughness was evaluated using surface profilometry, X-ray computed tomography (XCT), and optical microscopy (OM). Profilometry and OM provided localized measurements, whereas XCT captured full-channel roughness along the build direction. Results show that increasing LED initially reduces surface roughness due to improved melting and removal of partially fused particles, reaching optimal smoothness at an intermediate LED. Further LED increase causes roughness to rise again, attributed to balling and dross formation. Optical cross-sections depicted these trends, and XCT measurements closely matched profilometry data. The findings in this study highlight a trade-off between surface quality and dimensional accuracy, as higher LEDs improve smoothness but reduce channel diameter. This work establishes an optimal contour LED range for minimizing as-built surface roughness in fine internal channels, which can enhance the functional performance of PBF-LB components in aerospace, medical, and energy applications.
{"title":"Influence of contour parameters on the surface roughness of fine channels produced by powder bed fusion-laser beam","authors":"Jitendar Kumar Tiwari , Bala Malladi , Tatiana Mishurova , Tobias Fritsch , Lars Nyborg , Yu Cao","doi":"10.1016/j.vacuum.2026.115085","DOIUrl":"10.1016/j.vacuum.2026.115085","url":null,"abstract":"<div><div>Surface roughness strongly influences the performance of fine internal channels in additively manufactured components. This study investigates how contour process parameters affect the surface finish of 1 mm-diameter channels produced by powder bed fusion–laser beam (PBF-LB). Five contour parameter sets with progressively increasing laser energy density (LED) were applied, while keeping infill parameters constant. Surface roughness was evaluated using surface profilometry, X-ray computed tomography (XCT), and optical microscopy (OM). Profilometry and OM provided localized measurements, whereas XCT captured full-channel roughness along the build direction. Results show that increasing LED initially reduces surface roughness due to improved melting and removal of partially fused particles, reaching optimal smoothness at an intermediate LED. Further LED increase causes roughness to rise again, attributed to balling and dross formation. Optical cross-sections depicted these trends, and XCT measurements closely matched profilometry data. The findings in this study highlight a trade-off between surface quality and dimensional accuracy, as higher LEDs improve smoothness but reduce channel diameter. This work establishes an optimal contour LED range for minimizing as-built surface roughness in fine internal channels, which can enhance the functional performance of PBF-LB components in aerospace, medical, and energy applications.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115085"},"PeriodicalIF":3.9,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977732","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}
In response to the critical material requirements in the field of long-wavelength infrared detection, this study systematically investigates the effect of growth temperature on the material quality and interfacial properties of long-wavelength superlattices. By growing InAs/GaSb type-II superlattice samples at different temperatures (360°C–460 °C), a variety of characterization techniques including atomic force microscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were employed to systematically analyze the influence of temperature on surface morphology, crystal quality, strain state, and interfacial chemical stability. The results indicate that the sample grown at 380 °C exhibits clear atomic step-flow morphology, low root-mean-square roughness (0.262 nm), sharp interfaces, and excellent period uniformity, demonstrating that this temperature represents the optimal condition for achieving high-quality layered growth of superlattices. This study provides a reliable process window and theoretical foundation for the high-quality superlattice materials required for high-performance long-wavelength infrared detectors.
{"title":"Growth temperature optimization for high-quality InAs/GaSb Type-II superlattices grown by MBE towards high-performance long-wavelength infrared detection","authors":"Rong Yan, Yuhao Chen, Zhenfei Xing, Jing Yu, Bingfeng Liu, Weiqiang Chen, Lidan Lu, Lianqing Zhu","doi":"10.1016/j.vacuum.2026.115083","DOIUrl":"10.1016/j.vacuum.2026.115083","url":null,"abstract":"<div><div>In response to the critical material requirements in the field of long-wavelength infrared detection, this study systematically investigates the effect of growth temperature on the material quality and interfacial properties of long-wavelength superlattices. By growing InAs/GaSb type-II superlattice samples at different temperatures (360°C–460 °C), a variety of characterization techniques including atomic force microscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were employed to systematically analyze the influence of temperature on surface morphology, crystal quality, strain state, and interfacial chemical stability. The results indicate that the sample grown at 380 °C exhibits clear atomic step-flow morphology, low root-mean-square roughness (0.262 nm), sharp interfaces, and excellent period uniformity, demonstrating that this temperature represents the optimal condition for achieving high-quality layered growth of superlattices. This study provides a reliable process window and theoretical foundation for the high-quality superlattice materials required for high-performance long-wavelength infrared detectors.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"247 ","pages":"Article 115083"},"PeriodicalIF":3.9,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025510","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 : 2026-01-09DOI: 10.1016/j.vacuum.2026.115082
Jin Tao , Mingyao Xiong , Dan Huang
Based on first-principles calculations and Boltzmann transport theory, this study systematically investigates the thermoelectric performance of the layered compound LiCuS. By analyzing atomic displacement parameters, crystal orbital Hamilton populations, and potential energy distributions, the underlying mechanisms governing its lattice thermal conductivity are elucidated. The calculation results indicate that the lattice thermal conductivity (κL) of LiCuS exhibits a significant reduction when four-phonon (4ph) scattering is included, compared to the case considering only three-phonon (3ph) scattering. At 300 K, the κL along the a(b) and c axis are determined to be 1.603 and 0.654 W m−1 K−1, respectively. At 900 K, the optimal ZT values for p-type and n-doped LiCuS reach 1.18 and 0.53. The results demonstrate that the layered LiCuS compound, benefiting from its unique crystal structure and phonon transport characteristics, is a highly promising thermoelectric material for medium to high temperature applications.
基于第一性原理计算和玻尔兹曼输运理论，系统地研究了层状复合LiCuS的热电性能。通过分析原子位移参数、晶体轨道汉密尔顿居群和势能分布，阐明了控制其晶格热导率的潜在机制。计算结果表明，与仅考虑三声子（3ph）散射相比，考虑四声子（4ph）散射时，LiCuS的晶格导热系数（κL）显著降低。在300 K时，沿a(b)和c轴的κL分别为1.603和0.654 W m−1 K−1。在900 K时，p型和n掺杂LiCuS的最佳ZT值分别为1.18和0.53。结果表明，层状LiCuS化合物由于其独特的晶体结构和声子输运特性，是一种非常有前途的中高温热电材料。
{"title":"Theoretical investigation on thermoelectric properties of layered LiCuS: Mechanism of antibonding-state-induced anharmonicity and the role of four-phonon scattering","authors":"Jin Tao , Mingyao Xiong , Dan Huang","doi":"10.1016/j.vacuum.2026.115082","DOIUrl":"10.1016/j.vacuum.2026.115082","url":null,"abstract":"<div><div>Based on first-principles calculations and Boltzmann transport theory, this study systematically investigates the thermoelectric performance of the layered compound LiCuS. By analyzing atomic displacement parameters, crystal orbital Hamilton populations, and potential energy distributions, the underlying mechanisms governing its lattice thermal conductivity are elucidated. The calculation results indicate that the lattice thermal conductivity (<em>κ</em><sub>L</sub>) of LiCuS exhibits a significant reduction when four-phonon (4ph) scattering is included, compared to the case considering only three-phonon (3ph) scattering. At 300 K, the <em>κ</em><sub>L</sub> along the <em>a</em>(<em>b</em>) and <em>c</em> axis are determined to be 1.603 and 0.654 W m<sup>−1</sup> K<sup>−1</sup>, respectively. At 900 K, the optimal <em>ZT</em> values for <em>p</em>-type and <em>n</em>-doped LiCuS reach 1.18 and 0.53. The results demonstrate that the layered LiCuS compound, benefiting from its unique crystal structure and phonon transport characteristics, is a highly promising thermoelectric material for medium to high temperature applications.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115082"},"PeriodicalIF":3.9,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977735","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 : 2026-01-09DOI: 10.1016/j.vacuum.2025.115009
Donghui Tian , Tao Song , Zhigang Wang , Jiahao Li , Xueshen Wang , Xu Li , Qian Lei , Yi Zhang , Fang Cheng , Shi Li , Jianping Sun
Three Mn-Co-Ni-Cu-O thermosensitive films and corresponding sensors were prepared using some new technical routes and manufacturing processes. The micro-morphology, chemical valence and crystal phase of the three thermosensitive films were analyzed using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), etc. The resistance-temperature characteristics of the three sensors in the regions of room temperature, general cooling temperature and low temperature were measured using a wheatstone bridge equipment and a self-developed low temperature resistance-temperature measurement system. The films had thickness of (7.73–7.82) μm and surface roughness of (15.9–22.7) nm. The films contained C, Mn, Co, Ni and O elements and their cations were Mn2+, Mn3+, Mn4+, Co2+, Ni2+ and Ni3+. The largest ratio of Mn3+/Mn4+ was 0.94 and the main phases were MnO2, CoMn2O4, MnNi2O4 and NiMn2O4. The resistances of the three sensors decreased with the increase of temperature in the room temperature of (288.15–308.15) K, which displayed a good negative temperature coefficient (NTC) linearity. The resistance-temperature relationships of the sensors in a range of continuous temperature change (10 K–294 K) revealed a NTC characteristic, a resistance jump phenomenon at low temperature of (10–40) K, a resistance-temperature linearity at the general cooling temperature of (33–50) K and the room temperature of (218–286) K. The sensor deposited at 450 min had the widest resistance-temperature linearity, i.e., the best temperature measurement performance. The best sensor was characteristic without shedding or cracking, resistance smaller than 0.4 kΩ without annealing.
{"title":"Development of a novel negative temperature coefficient thermistor sensor with wide resistance-temperature linearity","authors":"Donghui Tian , Tao Song , Zhigang Wang , Jiahao Li , Xueshen Wang , Xu Li , Qian Lei , Yi Zhang , Fang Cheng , Shi Li , Jianping Sun","doi":"10.1016/j.vacuum.2025.115009","DOIUrl":"10.1016/j.vacuum.2025.115009","url":null,"abstract":"<div><div>Three Mn-Co-Ni-Cu-O thermosensitive films and corresponding sensors were prepared using some new technical routes and manufacturing processes. The micro-morphology, chemical valence and crystal phase of the three thermosensitive films were analyzed using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), etc. The resistance-temperature characteristics of the three sensors in the regions of room temperature, general cooling temperature and low temperature were measured using a wheatstone bridge equipment and a self-developed low temperature resistance-temperature measurement system. The films had thickness of (7.73–7.82) μm and surface roughness of (15.9–22.7) nm. The films contained C, Mn, Co, Ni and O elements and their cations were Mn<sup>2+</sup>, Mn<sup>3+</sup>, Mn<sup>4+</sup>, Co<sup>2+</sup>, Ni<sup>2+</sup> and Ni<sup>3+</sup>. The largest ratio of Mn<sup>3+</sup>/Mn<sup>4+</sup> was 0.94 and the main phases were MnO<sub>2</sub>, CoMn<sub>2</sub>O<sub>4</sub>, MnNi<sub>2</sub>O<sub>4</sub> and NiMn<sub>2</sub>O<sub>4</sub>. The resistances of the three sensors decreased with the increase of temperature in the room temperature of (288.15–308.15) K, which displayed a good negative temperature coefficient (NTC) linearity. The resistance-temperature relationships of the sensors in a range of continuous temperature change (10 K–294 K) revealed a NTC characteristic, a resistance jump phenomenon at low temperature of (10–40) K, a resistance-temperature linearity at the general cooling temperature of (33–50) K and the room temperature of (218–286) K. The sensor deposited at 450 min had the widest resistance-temperature linearity, i.e., the best temperature measurement performance. The best sensor was characteristic without shedding or cracking, resistance smaller than 0.4 kΩ without annealing.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115009"},"PeriodicalIF":3.9,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977734","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 : 2026-01-08DOI: 10.1016/j.vacuum.2026.115080
Yang Liu , Huanlin Zhu , Tianyu Wang , Mingyue Hu , Kaiqi Li , Zhicheng Yuan
To address the insufficient pressure resistance of ferrofluid seals under the operating conditions involving large shaft diameter and wide gaps, which makes it difficult to meet vacuum sealing requirements, a ferrofluid seal with non-uniform opposing pole teeth (FFS-NOPT) structure was designed, along with a compatible kerosene-based ferrofluid. Based on the pressure resistance theory of ferrofluid seals, subsequently, simulations for static magnetic field were conducted to systematically analyze the effects of key structural parameters, including pole tooth height and width, sealing gap, and tooth groove width on the sealing performance. The results indicate that the oleic acid-modified Fe3O4 nanoparticles, exhibiting an average size of approximately 8.3 nm and a saturation magnetization of 57.4 emu/g, demonstrate superparamagnetic properties. Consequently, the ferrofluid prepared achieves a saturation magnetization of 35.67 kA/m. In addition, simulation results show that the pressure resistance of FFS-NOPT is significantly influenced by the height of pole tooth, and increases with the increasing tooth groove width. Compared to conventional structures with identical structural dimensions, the FFS-NOPT exhibits approximately 57 % improvement in pressure resistance. These results demonstrate that this structure effectively enhances the pressure resistance of ferrofluid seals.
{"title":"Effect of non-uniform opposing tooth structure on the pressure resistance of ferrofluid seals","authors":"Yang Liu , Huanlin Zhu , Tianyu Wang , Mingyue Hu , Kaiqi Li , Zhicheng Yuan","doi":"10.1016/j.vacuum.2026.115080","DOIUrl":"10.1016/j.vacuum.2026.115080","url":null,"abstract":"<div><div>To address the insufficient pressure resistance of ferrofluid seals under the operating conditions involving large shaft diameter and wide gaps, which makes it difficult to meet vacuum sealing requirements, a ferrofluid seal with non-uniform opposing pole teeth (FFS-NOPT) structure was designed, along with a compatible kerosene-based ferrofluid. Based on the pressure resistance theory of ferrofluid seals, subsequently, simulations for static magnetic field were conducted to systematically analyze the effects of key structural parameters, including pole tooth height and width, sealing gap, and tooth groove width on the sealing performance. The results indicate that the oleic acid-modified Fe<sub>3</sub>O<sub>4</sub> nanoparticles, exhibiting an average size of approximately 8.3 nm and a saturation magnetization of 57.4 emu/g, demonstrate superparamagnetic properties. Consequently, the ferrofluid prepared achieves a saturation magnetization of 35.67 kA/m. In addition, simulation results show that the pressure resistance of FFS-NOPT is significantly influenced by the height of pole tooth, and increases with the increasing tooth groove width. Compared to conventional structures with identical structural dimensions, the FFS-NOPT exhibits approximately 57 % improvement in pressure resistance. These results demonstrate that this structure effectively enhances the pressure resistance of ferrofluid seals.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115080"},"PeriodicalIF":3.9,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927251","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 : 2026-01-07DOI: 10.1016/j.vacuum.2026.115071
Brahim el Khalil Oulad Naoui , Said Nemmich , Kamel Nassour , Essama Ahmed Ghaitaoui , Noureddine Oulad Naoui , El Mabrouk Khelifi , Amar Tilmatine
This study experimentally investigated a double-gap dielectric barrier discharge (DBD) reactor for ozone generation, comparing it to a conventional single-gap design under identical operating conditions. Electric field simulations revealed that the double-gap configuration achieved a more uniform and intensified electric field, with peak values reaching 1.4 × 10 7 V/m, substantially surpassing the single-gap's peak value of about 1 × 10 7 V/m. Voltage-current characteristics, Lissajous figures, and waveform analysis confirmed improved discharge behavior and reduced energy consumption in the double-gap reactor (19.5 W vs. 29.5 W). The influence of frequency, voltage, and oxygen flow rate on performance was also evaluated. In terms of performance, the DBD-DG system produced approximately 4.5–5.0 g/h of ozone, compared to 3.5–4.0 g/h for the DBD-SG, and achieved an energy efficiency of 250 g/kWh, twice that of the DBD-SG (125 g/kWh). These results establish the double-gap configuration as a promising, energy-efficient alternative for scalable, high-yield ozone generation.
本研究对双间隙介质阻挡放电（DBD）反应器进行了实验研究，并在相同的操作条件下将其与传统的单间隙设计进行了比较。电场模拟结果表明，双间隙结构获得了更均匀、更强的电场，峰值达到1.4 × 10 7 V/m，大大超过了单间隙结构约1 × 10 7 V/m的峰值。电压电流特性、Lissajous图和波形分析证实，双间隙电抗器（19.5 W vs 29.5 W）改善了放电行为，降低了能耗。实验还评估了频率、电压和氧流量对性能的影响。在性能方面，DBD-DG系统产生约4.5-5.0 g/h的臭氧，而DBD-SG为3.5-4.0 g/h，实现了250 g/kWh的能源效率，是DBD-SG （125 g/kWh）的两倍。这些结果建立了双间隙配置作为一个有前途的，节能的替代方案，可扩展，高产臭氧产生。
{"title":"A novel double-gap dielectric barrier discharge (DG-DBD) for enhanced ozone generation","authors":"Brahim el Khalil Oulad Naoui , Said Nemmich , Kamel Nassour , Essama Ahmed Ghaitaoui , Noureddine Oulad Naoui , El Mabrouk Khelifi , Amar Tilmatine","doi":"10.1016/j.vacuum.2026.115071","DOIUrl":"10.1016/j.vacuum.2026.115071","url":null,"abstract":"<div><div>This study experimentally investigated a double-gap dielectric barrier discharge (DBD) reactor for ozone generation, comparing it to a conventional single-gap design under identical operating conditions. Electric field simulations revealed that the double-gap configuration achieved a more uniform and intensified electric field, with peak values reaching 1.4 × 10 7 V/m, substantially surpassing the single-gap's peak value of about 1 × 10 7 V/m. Voltage-current characteristics, Lissajous figures, and waveform analysis confirmed improved discharge behavior and reduced energy consumption in the double-gap reactor (19.5 W vs. 29.5 W). The influence of frequency, voltage, and oxygen flow rate on performance was also evaluated. In terms of performance, the DBD-DG system produced approximately 4.5–5.0 g/h of ozone, compared to 3.5–4.0 g/h for the DBD-SG, and achieved an energy efficiency of 250 g/kWh, twice that of the DBD-SG (125 g/kWh). These results establish the double-gap configuration as a promising, energy-efficient alternative for scalable, high-yield ozone generation.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115071"},"PeriodicalIF":3.9,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927252","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 : 2026-01-07DOI: 10.1016/j.vacuum.2026.115073
Xiaopeng Xu , Xinyu Jin , Tao Guo , Xuesong Zhou , Chuntai Gao , Wenjing Ma , Jinghua Wang , Le Fan , Sihui Wang
Non-evaporable getter (NEG) films are essential for achieving and maintaining ultra-high vacuum in fourth-generation light sources, such as the Hefei Advanced Light Facility (HALF), where their performance directly impacts beam quality and stability. With the ongoing construction of the HALF, depositing high-quality NEG films has become a decisive factor for the overall vacuum performance. In this study, Ti-Zr-V NEG films were deposited onto the inner walls of pipelines with various configurations employing direct current pulsed magnetron sputtering technology. The deposition system and challenges encountered during the process are described in detail. The vacuum performance and pumping capacity of the films were tested, while the microstructure and thickness were characterized by scanning electron microscopy. The results demonstrate that the deposition system operated stably and reliably, with no instances of incomplete film deposition or process interruptions. Repeated SEM analyses of the samples confirmed the consistency and uniformity of the film's morphology and composition. All coated pipelines achieved an ultimate vacuum below 2 × 10−8 Pa following sputter ion pump isolation, with the initial sticking probability for CO above 0.05 and adsorption capacities exceeding 1 × 10−5 mbar L/cm2. These results provide a solid technical foundation for the forthcoming large-scale deposition of NEG films in HALF vacuum systems.
{"title":"Coating technology and performance evaluation of batch-produced NEG films for the HALF storage ring vacuum chambers","authors":"Xiaopeng Xu , Xinyu Jin , Tao Guo , Xuesong Zhou , Chuntai Gao , Wenjing Ma , Jinghua Wang , Le Fan , Sihui Wang","doi":"10.1016/j.vacuum.2026.115073","DOIUrl":"10.1016/j.vacuum.2026.115073","url":null,"abstract":"<div><div>Non-evaporable getter (NEG) films are essential for achieving and maintaining ultra-high vacuum in fourth-generation light sources, such as the Hefei Advanced Light Facility (HALF), where their performance directly impacts beam quality and stability. With the ongoing construction of the HALF, depositing high-quality NEG films has become a decisive factor for the overall vacuum performance. In this study, Ti-Zr-V NEG films were deposited onto the inner walls of pipelines with various configurations employing direct current pulsed magnetron sputtering technology. The deposition system and challenges encountered during the process are described in detail. The vacuum performance and pumping capacity of the films were tested, while the microstructure and thickness were characterized by scanning electron microscopy. The results demonstrate that the deposition system operated stably and reliably, with no instances of incomplete film deposition or process interruptions. Repeated SEM analyses of the samples confirmed the consistency and uniformity of the film's morphology and composition. All coated pipelines achieved an ultimate vacuum below 2 × 10<sup>−8</sup> Pa following sputter ion pump isolation, with the initial sticking probability for CO above 0.05 and adsorption capacities exceeding 1 × 10<sup>−5</sup> mbar L/cm<sup>2</sup>. These results provide a solid technical foundation for the forthcoming large-scale deposition of NEG films in HALF vacuum systems.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115073"},"PeriodicalIF":3.9,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977731","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 : 2026-01-07DOI: 10.1016/j.vacuum.2026.115079
Yuqiu Ye, Yufeng Xia, Xue Bai, Lu Li
This work investigated the effect of post-extrusion annealing duration on the microstructural development and the resulting degradation behavior of Mg–2.5 Yb (wt%) extrusion alloys. Results indicated that the extruded sample presented a heterogeneous grain structure with high-density residual dislocations and coarse Mg2Yb second phases, leading to a strong localized corrosion tendency. After 1 h of annealing, incomplete recrystallization partially eliminated the residual dislocations, but failed to achieve complete microstructural homogenization. When the annealing duration was extended to 10 h, the residual strain was almost erased, but it triggered abnormal grain growth and Mg2Yb phase coarsening, thus reintroducing electrochemical inhomogeneity. In contrast, the sample after 3 h of annealing obtained a homogeneous grain structure with complete recrystallization and finely dispersed second phase. This homogenous microstructure effectively reduced the corrosion susceptibility of micro-galvanic and facilitated the development of a compact and thermodynamically stable Yb2O3-containing corrosion product film. Quantitative analysis of the corrosion behaviors confirmed that the sample annealed for 3 h obtained the smallest average corrosion depth, the best corrosion uniformity, the weakest anisotropy, and exhibited the most stable long-term degradation behavior. Furthermore, the mechanisms underlying the annealing-time-dependent microstructure and corrosion response were elucidated and correlated.
{"title":"Effect of annealing duration on the microstructure development and degradation behavior of Mg–2.5 Yb extrusion alloy","authors":"Yuqiu Ye, Yufeng Xia, Xue Bai, Lu Li","doi":"10.1016/j.vacuum.2026.115079","DOIUrl":"10.1016/j.vacuum.2026.115079","url":null,"abstract":"<div><div>This work investigated the effect of post-extrusion annealing duration on the microstructural development and the resulting degradation behavior of Mg–2.5 Yb (wt%) extrusion alloys. Results indicated that the extruded sample presented a heterogeneous grain structure with high-density residual dislocations and coarse Mg<sub>2</sub>Yb second phases, leading to a strong localized corrosion tendency. After 1 h of annealing, incomplete recrystallization partially eliminated the residual dislocations, but failed to achieve complete microstructural homogenization. When the annealing duration was extended to 10 h, the residual strain was almost erased, but it triggered abnormal grain growth and Mg<sub>2</sub>Yb phase coarsening, thus reintroducing electrochemical inhomogeneity. In contrast, the sample after 3 h of annealing obtained a homogeneous grain structure with complete recrystallization and finely dispersed second phase. This homogenous microstructure effectively reduced the corrosion susceptibility of micro-galvanic and facilitated the development of a compact and thermodynamically stable Yb<sub>2</sub>O<sub>3</sub>-containing corrosion product film. Quantitative analysis of the corrosion behaviors confirmed that the sample annealed for 3 h obtained the smallest average corrosion depth, the best corrosion uniformity, the weakest anisotropy, and exhibited the most stable long-term degradation behavior. Furthermore, the mechanisms underlying the annealing-time-dependent microstructure and corrosion response were elucidated and correlated.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115079"},"PeriodicalIF":3.9,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927250","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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