Vacuum最新文献

{"title":"Growth mode evolution and quality improvement of CVD diamond growth: role of substrate orientation","authors":"Yingnan Wang,&nbsp;Chuanwen Song,&nbsp;Saibin Han,&nbsp;Ziang Wang,&nbsp;Xiaoyu Zhang,&nbsp;Xiufei Hu,&nbsp;Lei Ge,&nbsp;Mingsheng Xu,&nbsp;Yan Peng,&nbsp;XiWei Wang,&nbsp;Xiaobo Hu,&nbsp;Xiangang Xu","doi":"10.1016/j.vacuum.2025.114554","DOIUrl":"10.1016/j.vacuum.2025.114554","url":null,"abstract":"<div><div>The effect of misorientation angles of diamond substrate on the epitaxial diamond layer grown by microwave plasma chemical vapor deposition (MPCVD) has been investigated. The surface morphology, impurity incorporation and dislocation density of epilayer are significantly influenced by the misorientation angels of diamond substrate along to the &lt;110&gt;. Herein, the substrate with 3–4° miscut angles is considered to be most suitable for deposited diamond layer, which enables to grow the high-quality crystal exhibiting macroscopically flat surfaces while effectively suppressing unintentional impurity incorporation. The dominant growth mode of diamond surface undergoes from island-growth mode to two-dimensional (2D) lateral growth mode and finally to step-flow growth mode. It is also found that the morphological features of hillock defects transit from pyramidal to triangular, attributed to reduced C-species adsorption on hillock surfaces and sustained step-flow advancement. The introduction of misorientation angles changes the nucleation process and growth kinetic characteristics of hillocks. The growth rate of flat surface increases and the number of surface hillocks decreases significantly. The growth rate increases from ∼3 μm/h to ∼9 μm/h. The density of hillocks is decreased from ∼300 cm⁻² to 0. Meanwhile, the average density of etching pits decreases from ∼10⁵ cm⁻² to ∼10⁴ cm⁻² with increasing off-axis angles. Based on crystal growth theory and Burton-Cabrera-Frank (BCF) theory, the relationship between the diffusion dynamics of C atoms and the misorientation angle is discussed. The substrate orientation promotes the adsorption process of C atoms at edge sites and changes the surface diffusion distance to achieve a flat surface, elucidating the underlying mechanism for angle-dependent control of surface morphological evolution.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114554"},"PeriodicalIF":3.8,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611784","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}

{"title":"Changes in the mechanical properties and structural condition of stainless steel AISI 301 caused by the combined effect of impact-oscillatory loading and cryogenic cooling. Effects caused by holding specimens in liquid nitrogen for 1 h","authors":"Mykola Chausov ,&nbsp;Pavlo Maruschak ,&nbsp;Andrii Pylypenko ,&nbsp;Vladyslav Shmanenko ,&nbsp;Maksym Lisnichuk ,&nbsp;Daria Yudina ,&nbsp;Pavol Sovák","doi":"10.1016/j.vacuum.2025.114541","DOIUrl":"10.1016/j.vacuum.2025.114541","url":null,"abstract":"<div><div>The main patterns of the combined effect of impact-oscillatory loading (IOL) (dynamic non-equilibrium processes (DNP)) and cryogenic cooling on changes in the structural condition and mechanical properties of stainless steel AISI 301 are described. In our experiment, the steel was first immersed in liquid nitrogen for 1 h and then subjected to static tensioning at normal temperature. New structural and mechanical conditions of steel AISI 301 that occurred under DNP (ε_imp = 7.75 … 13.5 %) are scrutinised. In particular, it was found that for ε_imp = 10 … 11.5 %, the ultimate strength of the steel that was further subjected to static tensioning at normal temperature increased appreciably, and the ductility decreased. With ε_imp ∼10 %, the ultimate strength increased by 13.9 % compared to the baseline steel, but the relative strain remained at the level of 3.85 %. The structural conditions of steel AISI 301 and their link to new mechanical properties were studied by physical methods. A physical explanation is given for a rapid decline in steel ductility when ε_imp was in the range from 10.0 % to 11.5 %. With repeated static tensioning, when ε_imp was above 11.5 %, the ultimate strength increased significantly and ductility increased only slightly. When ε_imp was 13.5 %, the ultimate strength increased to 40 % compared to the baseline steel, and strain remained at the level of 7.22 %. Thus, the detected ranges of the intensity of the DNP during cryogenic cooling, at which the mechanical properties of steel, in particular plasticity, are significantly deteriorated, which is dangerous during the operation of aerospace structures.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114541"},"PeriodicalIF":3.8,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570250","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}

{"title":"Design and study on a dispersive ferrofluid seal with opposite pole teeth for gas sealing conditions","authors":"Xiaolong Yang ,&nbsp;You Li ,&nbsp;Xuankai Dou ,&nbsp;Liping Jiang","doi":"10.1016/j.vacuum.2025.114553","DOIUrl":"10.1016/j.vacuum.2025.114553","url":null,"abstract":"<div><div>When the rotating shaft operates under high-speed and heavy-load conditions, significant radial runout will occur. The sealing pressure capability of the common ferrofluid (FF) seal drops sharply under large sealing clearance (SC), so it is impossible to achieve gas sealing under vacuum or high-pressure conditions. To improve the pressure capability, a dispersive FF seal with opposite pole teeth (DFS-OPT) was designed, and thus the effects of SC sizes, the number of pole teeth (PT) and OPT, the OPT eccentricity distance, and the rotational speed on the sealing performance of DFS-OPT were analyzed through numerical simulation and experimental methods. The results show that the experimental values are in good agreement with the theoretical values, and both are significantly higher than the pressure capability of common FF seals, meeting the sealing requirements for high-air-pressure conditions under large SC. At linear speeds below 3.4 m/s, rotational speed has minimal effect, and even at a linear speed of 10.2 m/s, the sealing pressure capability can still exceed 1 atm. This broadens the application scope of FF seals.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114553"},"PeriodicalIF":3.8,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522088","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}

{"title":"Influence of water vapor on Nujol adsorption and desorption on quartz and calcite surfaces: A near-ambient pressure X-ray photoelectron spectroscopy and ambient atomic force microscopy study","authors":"E. Annese ,&nbsp;L.I.M. Sinimbu ,&nbsp;F. Stavale","doi":"10.1016/j.vacuum.2025.114512","DOIUrl":"10.1016/j.vacuum.2025.114512","url":null,"abstract":"<div><div>The stability of oil/substrate interaction upon external stimuli is a critical issue for enhanced oil recovery (EOR) processes and catalytic applications. In this study, we address how the Nujol films behaves on well-defined SiO₂(001) and CaCO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>(104) surfaces against water vapor pressure (2 mbar) and ultra-high vacuum (UHV) environment (10⁻¹⁰ mbar) by in-situ near-ambient pressure X-ray photoelectron spectroscopy measurement (NAP-XPS) and ex-situ by atomic force microscopy (AFM). The specimen conditioning with Nujol resulted in a film of <span><math><mo>∼</mo></math></span> 2 nm on SiO₂ and up 4 nm on CaCO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>. The chemical composition of Nujol/SiO₂ interface does not vary significantly against treatment, although its topography passes from continuous to cluster like in DW/Nujol/SiO₂ interface. In Nujol/CaCO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> interface oil component reduces by: (i) 20% in UHV and (ii) <span><math><mo>∼</mo></math></span> 60% after controlled exposure to DW vapor pressure (2 mbar). The modification of interface chemical composition is reflected into the alteration of Nujol film topography on CaCO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> that varies from continuous to fragmented film after 12 h in UHV and substantially reorganizes itself after exposure to p(H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O) = 2 mbar. Our results highlight the role of water in reshaping the oil-oxide interface under controlled environmental conditions and its relevance in oil removal process.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114512"},"PeriodicalIF":3.8,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144595683","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}

{"title":"Thermal diffusion-driven formation of CuSbS2 from Co-evaporated Cu and Sb2S3 for photovoltaics","authors":"S. Heera,&nbsp;A. Sujith,&nbsp;K.G. Deepa","doi":"10.1016/j.vacuum.2025.114549","DOIUrl":"10.1016/j.vacuum.2025.114549","url":null,"abstract":"<div><div>CuSbS₂ is an emerging, earth-abundant material with strong potential as a solar cell absorber. In this work, CuSbS₂ thin films are prepared by diffusing copper into antimony trisulphide (Sb₂S₃) through co-evaporation under low-pressure conditions, and their application in solar cells is demonstrated. The as-deposited samples are amorphous in nature, and their crystallinity improved with thermal treatment at various temperatures, reaching a maximum at 375 °C. The sample composition is varied to determine the optimal stoichiometry achievable with the current deposition method. All the samples exhibited sulfur-poor stoichiometry, and selenium doping is employed to compensate for the sulfur deficiency in the material. The conductivity of the CuSbS₂ film improved upon doping with a small amount of Se. Solar cell is fabricated in the configuration Au/p-CuSbS₂/n-Si/Al using both doped and undoped CuSbS₂. The conversion efficiency improved from 0.15 to 0.7 % with Se doping.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114549"},"PeriodicalIF":3.8,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514254","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}

{"title":"Microstructural charactristics of laser repaired Rene 142 turbine vane using Hastelloy W and C263 filler metals under high-temperature burner-rig test","authors":"Ali Khorram ,&nbsp;Hasan Meraji","doi":"10.1016/j.vacuum.2025.114552","DOIUrl":"10.1016/j.vacuum.2025.114552","url":null,"abstract":"<div><div>In this study, the repair of René-142 was performed using pulsed laser welding with two different filler metals: Hastelloy W (HW) and C263. HW was employed for the initial two weld passes, followed by five passes with C263. Following the repair process, the specimens were exposed to the burner-rig test at 900 °C for periods of 1 h and 200 h. The results revealed that, before the burner-rig test, the base metal exhibited a γ-phase matrix containing coarse, cuboidal γ′ precipitates, along with tantalum and tungsten carbide particles. A 1-h burner-rig test did not significantly alter the microstructure of the base metal. However, after 200 h, γ′′ precipitates replaced the γ′ precipitates, leading to a hardness reduction from 360 to 310 Vickers. Both HW and C263 initially exhibited a single γ phase. The 1-h burner-rig test led to the formation of grain boundary and intragranular Ni₂Mo and Ni₃Mo precipitates in the HW, increasing the hardness value from 360 to 420 Vickers. In contrast, C263 maintained microstructural stability after 1-h burner-rig test, decreasing the hardness value from 350 to 290 Vickers. Following 200-h burner-rig test, the microstructure of HW revealed a higher density of coarser NiMo precipitates, contributing to a hardness increase up to 511 Vickers. Additionally, coarse NiMo precipitates formed in the dilution zones of both C263 and HW. Nonetheless, C263 retained its single-phase structure, and its hardness decreased to 260 Vickers compared to the 1-h burner-rig test due to increased grain growth.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114552"},"PeriodicalIF":3.8,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518336","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}

{"title":"New dynamic FIB-SEM fusion model for controllable high-precision nanofabrication with high-energy synchronous FIB-SEM beams","authors":"Lirong Zhao,&nbsp;Yimin Cui,&nbsp;Hao Yin,&nbsp;Liyuheng Rui,&nbsp;Wenping Li","doi":"10.1016/j.vacuum.2025.114547","DOIUrl":"10.1016/j.vacuum.2025.114547","url":null,"abstract":"<div><div>With the advantages of high-resolution fabrication of FIB and real-time imaging of SEM, the FIB-SEM synchronous system has been widely used in in-situ nanofabrication of semiconductors, life science, new energy, etc. Its machining accuracy and quality can be improved by controlling ion neutralization and sample charge accumulation with the electron beam (EB). In this paper, a new dynamic FIB-SEM fusion beam was developed for a 30 kV gallium FIB-SEM system by considering the SEM regulation on interionic Coulomb force and the modulation of sample surface potential on FIB. Based on three-dimension (3D) FIB/SEM beam current density distributions, the fusion model was complemented by GPU-accelerated algorithm for solving the multi-particle dynamics in the coupled ion-electron system, and verified by sputtering experiments on Si and PMMA. Results show that the machining accuracy on Si can be improved up to 17 % for FIB of 30 pA wtih a 5 keV EB of 1.6 nA, and it will be ∼30 % on PMMA for FIB of 80 pA with a 3 keV EB of 170 pA. The model will provide guidance for controllable high-precision FIB-SEM nanofabrication in both conductive and insulating materials.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114547"},"PeriodicalIF":3.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522086","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}

{"title":"Investigating the role of shot peening pressure on microstructure, grain structure, and hydrogen embrittlement of age-hardened copper alloy","authors":"Juan Xu,&nbsp;Wenbo Ding","doi":"10.1016/j.vacuum.2025.114551","DOIUrl":"10.1016/j.vacuum.2025.114551","url":null,"abstract":"<div><div>This paper explores the effect of shot peening pressure (0.2, 0.5, and 0.8 MPa) on grain structure, hardness, and hydrogen embrittlement of age-hardened copper alloy. The micro-sized and nano-sized precipitates were observed in age-hardened alloy. The shot-peened surfaces showed higher hardness and refined grain structure than untreated surfaces. By increasing the peening pressure, the hardness increased while the grain size decreased. The maximum hardness values were 302, 311, and 325 HV after shot peening pressures of 0.2, 0.5, and 0.8 MPa, respectively. Also, the average grain sizes were 33, 25, and 18 μm, respectively. In addition, the elongation of shot-peened alloys increased versus peening pressure. The elongation values increased from 18.5 % after the shot peening pressure of 0.2 MPa–23.5 % after the shot peening pressure of 0.8 MPa, respectively. In the presence of hydrogen, the fraction of brittle fracture decreased at higher peening pressure.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114551"},"PeriodicalIF":3.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144536157","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}

{"title":"Influence of Mo content on the metal-insulator transition of Mo-doped VO2 single crystals fabricated by fast thermal oxidation","authors":"Fu Xie ,&nbsp;Haiying Qi ,&nbsp;Yiwang Zheng ,&nbsp;Mingxi Xie ,&nbsp;Haorong Li ,&nbsp;Minglong Xu ,&nbsp;Chunwang Zhao ,&nbsp;Shikuan Sun","doi":"10.1016/j.vacuum.2025.114548","DOIUrl":"10.1016/j.vacuum.2025.114548","url":null,"abstract":"<div><div>Vanadium dioxide (VO₂) has demonstrated potentials for applications in sensors, actuators, intelligent windows, and devices for storing energy, owing to its unique metal-insulator transition (MIT) property at around 67 °C accompanied by a structural transition between rutile and monoclinic phases. In order to enhance its practicality at ambient temperature, Mo-doped VO₂ single crystals with varying Mo contents were fabricated in the present work by a facile thermal-oxidation process in air. The Mo-doped VO₂ single crystal exhibits a rod-shaped and hollow morphology with a rectangular cross-section. The influence of Mo doping on the phase transition behavior of Mo-doped VO₂ single crystals was investigated. The analysis and energy dispersion spectrum maps revealed the homogenous distribution of Mo, V, and O elements across the single crystals, confirming successful doping. High-resolution transmission electron microscopy images and electron diffraction patterns verified the single-crystal characteristic of the Mo-doped VO₂. X-ray photoelectron spectroscopy indicated the presence of mixed valence states of V (V⁴⁺ and V⁵⁺) and Mo⁶⁺, while differential scanning calorimetry measurements demonstrated a substantial reduction in the MIT temperature by approximately 50 °C/at% Mo, which reaches the highest decrease efficiency for metal-insulator transition temperature of element-doped VO₂.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114548"},"PeriodicalIF":3.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514270","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}

{"title":"Improved design of magnetic trap system for cold atomic vacuum measurements","authors":"Cun Feng,&nbsp;Yongjun Cheng,&nbsp;Meng Dong,&nbsp;Yafei Zhang,&nbsp;Xiaojie Kang,&nbsp;Tianyou Feng,&nbsp;Wenjie Jia,&nbsp;Dong Fan,&nbsp;Wenjun Sun","doi":"10.1016/j.vacuum.2025.114544","DOIUrl":"10.1016/j.vacuum.2025.114544","url":null,"abstract":"<div><div>The technique of measuring vacuum based on the loss rate of cold atoms in magnetic trap is expected to establish a primary vacuum standard in the ultra-high vacuum/extreme-high vacuum. However, there are Majorana losses in quadrupole trap installed in current systems that can affect the accuracy of cold atom vacuum measurements. To solve this problem, we design the optimal parameters of cloverleaf trap which is suitable for vacuum measurements. The structure was designed to produce a magnetic field with the curvature of 20 G/cm², the gradient of 23.7 G/cm, and the maximum temperature rise was evaluated to be 14.90 °C. The Majorana loss rate in the cloverleaf trap was calculated based on the loss rate equation under high temperatures (<em>k</em>_<em>B</em><em>T</em>&gt;2<em>ћω</em>). Additionally, the number of atoms trapped in magnetic trap was estimated based on the trap depth. The results demonstrate that, under bias field of 19 G, the error in vacuum pressure inversion due to Majorana losses is as low as 2.5 × 10⁻¹² Pa. This indicates a significant suppression of Majorana losses. The magnetic trap is capable of trapping 2.73× 10⁶ atoms, a number sufficient to invert the vacuum pressure.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114544"},"PeriodicalIF":3.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522089","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}