IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-11 DOI: 10.1016/j.vacuum.2025.114245

Min Wei, Haibin Liu, Lezhi Ye, Yanfeng Wei

{"title":"Thermodynamic modelling and working characteristic analysis of claw vacuum pumps with a particular mixing process","authors":"Min Wei, Haibin Liu, Lezhi Ye, Yanfeng Wei","doi":"10.1016/j.vacuum.2025.114245","DOIUrl":"10.1016/j.vacuum.2025.114245","url":null,"abstract":"<div><div>The claw vacuum pump only relies on a pair of intermeshing claw rotors to produce an internal compression process, so it exhibits many distinct advantages and plays an important role in vacuum application field. Different from other positive displacement vacuum pumps or compressors, the claw vacuum pump contains a unique and inevitable mixing process in its working process due to the existence of the carryover formed by two claw rotors. To reveal the mechanism of the mixing process, this paper established a thermodynamic model of the claw vacuum pump to describe gas mixing process among multiple working chambers. An indicated power diagram, called <em>p</em>-<em>V</em> diagram, of the claw vacuum pump including the suction, mixing, compression and discharge processes was obtained and analyzed. Effects of the mixing process on the working characteristics in terms of the compression ratio, indicated power and discharge temperature of the claw vacuum pump were discussed. It is found that the mixing process includes an over-compression process of the carryover and an expansion process before the suction process, and the mixing process leads to the reduction of the adiabatic efficiency and the increase of the indicated power. Meanwhile, it increases the gas pressure by gas-mixing before the compression process, which increases the compression ratio. This study is of great significance for the design of claw vacuum pumps.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114245"},"PeriodicalIF":3.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628778","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}

引用次数: 0

The updated gas sensing performance of In2O3 porous nanospheres for ppb level formaldehyde by doping with Mo Mo掺杂改善了In2O3多孔纳米球对ppb级甲醛的气敏性能

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-10 DOI: 10.1016/j.vacuum.2025.114248

Xiaohua Wang , Yanwei Li , Xinhui Jin , Guang Sun , Jianliang Cao , Yan Wang

{"title":"The updated gas sensing performance of In2O3 porous nanospheres for ppb level formaldehyde by doping with Mo","authors":"Xiaohua Wang , Yanwei Li , Xinhui Jin , Guang Sun , Jianliang Cao , Yan Wang","doi":"10.1016/j.vacuum.2025.114248","DOIUrl":"10.1016/j.vacuum.2025.114248","url":null,"abstract":"<div><div>Rapidly and highly sensitive detection of formaldehyde (HCHO) at ppb level by using metal oxide semiconductor (MOS) based gas sensor has attracted growing attention due to the urgent need for environmental and health protection. Herein, molybdenum (Mo) doping strategy was proposed to improve the formaldehyde (HCHO) sensitivity of In<sub>2</sub>O<sub>3</sub> porous nanospheres (PNSs), which enables them to monitor ppb level HCHO at a relatively lower temperature. The Mo-doped In<sub>2</sub>O<sub>3</sub> (Mo–In<sub>2</sub>O<sub>3</sub>) PNSs were prepared through a freeze-drying and calcination route by using hydrothermally synthesized In(OH)<sub>3</sub> as a precursor. As applied as an active material for detecting HCHO, Mo–In<sub>2</sub>O<sub>3</sub> PNSs showed some impressive improvements as compared with bare In<sub>2</sub>O<sub>3</sub> counterparts, such as lower operating temperature (300 °C vs 120 °C), higher response (17 vs 1.92 for 1.03 ppm HCHO), the shorter response time (324 s vs 423 s), and better selectivity. Even to 10.3 ppb HCHO, the Mo–In<sub>2</sub>O<sub>3</sub> sensor can give a response of 2.44, revealing its limit of detection (LOD) for HCHO can be as low as 10.3 ppb. The multiple sensitization effects in Mo–In<sub>2</sub>O<sub>3</sub> PNSs as well as their behind mechanism were discussed.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114248"},"PeriodicalIF":3.8,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143632005","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}

引用次数: 0

Evolution of microstructure, anti-oxidation and tribological properties of CrAlN and VN based coatings in a wide temperature range CrAlN和VN基涂层在宽温度范围内的组织演变、抗氧化和摩擦学性能

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-10 DOI: 10.1016/j.vacuum.2025.114244

Liang Li , Liwei Zheng , Hao Lin , Kai Le , Yuzhen Liu , Hongyu Li , Zhenlin Yang , Shusheng Xu

{"title":"Evolution of microstructure, anti-oxidation and tribological properties of CrAlN and VN based coatings in a wide temperature range","authors":"Liang Li , Liwei Zheng , Hao Lin , Kai Le , Yuzhen Liu , Hongyu Li , Zhenlin Yang , Shusheng Xu","doi":"10.1016/j.vacuum.2025.114244","DOIUrl":"10.1016/j.vacuum.2025.114244","url":null,"abstract":"<div><div>To improve the wear resistance of Ni-based alloys at elevated temperatures, the CrAlN/VN multilayer coating was deposited by multi-arc ion plating. The wear tests at room temperature, 300, 500, and 700 °C were adopted to evaluate the tribology performance. The CrAlN/VN coating showed a dense cross-sectional structure, and the surface roughness of the multilayer coating was measured to be 85.3 nm, which is lower than that of the CrAlN coatings (101.7 nm). It indicates that the multilayer structure contributes to a smoother surface, which is beneficial for reducing friction and wear. The nanoindentation test showed that the hardness of the multilayer coating was 26.1 GPa, respectively, which was higher than those of the VN (18.8 GPa) and CrAlN (24.5 GPa) coatings. The CrAlN/VN multilayer coating displayed the lowest wear rate at 500 °C, which was about 3.2 × 10<sup>−6</sup> mm<sup>3</sup>/N⋅m. The superior wear resistance of the multilayer coating was attributed to the formation of oxides at high temperatures. The wear rate of the coating will be significantly accelerated when the operating temperature exceeds the melting point of V<sub>2</sub>O<sub>5</sub>. This study provides a new strategy for the anti-wear protection of nickel-based alloys in a wide temperature range.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114244"},"PeriodicalIF":3.8,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610163","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}

引用次数: 0

The influence of total reactor pressure on PECVD growth of carbon nanotubes 反应器总压力对碳纳米管PECVD生长的影响

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-10 DOI: 10.1016/j.vacuum.2025.114242

Sergey V. Bulyarskiy, Mikhail S. Molodenskiy, Pavel E. L'vov, Alexander A. Pavlov, Yuri V. Anufriev, Yuri P. Shaman, Georgy G. Gusarov, Kirill A. Modestov, Artem V. Sysa, Alexander R. Shevchenko

引用次数: 0

A high performance gas sensor for n-butanol based on DyFeO3 was prepared by one step hydrothermal method 采用一步水热法制备了基于DyFeO3的高性能正丁醇气体传感器

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-10 DOI: 10.1016/j.vacuum.2025.114243

Heng Wang, Shuyi Ma, Ping Ni, Gege Fan, Jiayun Guo, Nina Ma, Jiming Liu, Chengyu Xu, Jinsha Wei, Wei Wei, Yinyue Wang, Jiamin Zhu

引用次数: 0

The peculiar neutralization behavior in grazing scattering of Na+ ions at high-work-function metal surfaces 高功函数金属表面Na+离子掠掠散射的特殊中和行为

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-08 DOI: 10.1016/j.vacuum.2025.114238

Bo Jin, Chenxi Han, Xiaogang Wang, Yibin Mao, Yin Li, Yanling Guo, Lin Chen, Ximeng Chen

{"title":"The peculiar neutralization behavior in grazing scattering of Na+ ions at high-work-function metal surfaces","authors":"Bo Jin, Chenxi Han, Xiaogang Wang, Yibin Mao, Yin Li, Yanling Guo, Lin Chen, Ximeng Chen","doi":"10.1016/j.vacuum.2025.114238","DOIUrl":"10.1016/j.vacuum.2025.114238","url":null,"abstract":"<div><div>The efficient neutralization of alkali-metal ions on high-work-function metal surfaces at low incident energies has not been understood well at present. To study this mechanism, we measured the neutral fraction of Na<sup>+</sup> ions scattering on the high-work-function Pd(111) and Au(111) surfaces at the 7<sup>o</sup> scattering angle in the energy range of 0.2–5 keV. The non-monotonic exit-angle dependent neutral fraction for 0.3 keV Na<sup>+</sup> ions has been obtained. The neutral fractions sharply decrease to about zero with the increase of incident energy, which is different from our previous work at large scattering angle. It indicates that the scattering angle has a great influence to the neutralization. The calculations show that the neutral atoms which efficiently formed at short ion-surface distances spend more time at large distances when departing from the surface at the grazing scattering angle and lose the electron to finally become positive ions, which qualitatively explains the less neutral fraction observed experimentally.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114238"},"PeriodicalIF":3.8,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610161","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}

引用次数: 0

Microstructural evolution and mechanical properties in rapid sintered Ti5Si3/Ti matrix composites with varying Si additions 不同Si添加量快速烧结Ti5Si3/Ti基复合材料的组织演变和力学性能

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-08 DOI: 10.1016/j.vacuum.2025.114240

Xinjiang Zhang , Chengcheng Peng , Cailiu Yin , Yujing Liu , Jianlie Liang , Guosheng Chen , Ruirun Chen , Shu Wang

{"title":"Microstructural evolution and mechanical properties in rapid sintered Ti5Si3/Ti matrix composites with varying Si additions","authors":"Xinjiang Zhang , Chengcheng Peng , Cailiu Yin , Yujing Liu , Jianlie Liang , Guosheng Chen , Ruirun Chen , Shu Wang","doi":"10.1016/j.vacuum.2025.114240","DOIUrl":"10.1016/j.vacuum.2025.114240","url":null,"abstract":"<div><div>Titanium matrix composites with varying Si additions were rapidly fabricated via spark plasma sintering, in-situ Ti<sub>5</sub>Si<sub>3</sub> particles were synthesized through a rapid sintering reaction between Ti and Si powders. The Ti<sub>5</sub>Si<sub>3</sub> particles were uniformly distributed within the Ti matrix of each sintered composite. As the Si content in the initial mixture increased, the size and quantity of the Ti<sub>5</sub>Si<sub>3</sub> particles grew significantly. In composites with lower Si content, in-situ Ti<sub>5</sub>Si<sub>3</sub> particles predominantly formed elongated rods, along with some coarse polygonal particles. With a further increase in Si content, Ti<sub>5</sub>Si<sub>3</sub> particles primarily took on polygonal shapes. When the Si content reached 5.0 wt%, Ti<sub>5</sub>Si<sub>3</sub> particles tended to transition into near-equiaxed structures. The semicoherent interface is formed between Ti and Ti<sub>5</sub>Si<sub>3</sub> phases, which greatly preserves the plastic deformation ability, even with a significant increase in yield strength as the silicon content increases to 5 %. The evolution of in-situ Ti<sub>5</sub>Si<sub>3</sub> and its corresponding mechanical effect were discussed.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114240"},"PeriodicalIF":3.8,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601254","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}

引用次数: 0

Electric field characterization in atmospheric-pressure pulsed bipolar plasma catalysis of organic waste gas 常压脉冲双极等离子体催化有机废气的电场表征

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-07 DOI: 10.1016/j.vacuum.2025.114126

Chen-Wei Liang , Yan-Xiang Huang , Chen-Jui Liang

{"title":"Electric field characterization in atmospheric-pressure pulsed bipolar plasma catalysis of organic waste gas","authors":"Chen-Wei Liang , Yan-Xiang Huang , Chen-Jui Liang","doi":"10.1016/j.vacuum.2025.114126","DOIUrl":"10.1016/j.vacuum.2025.114126","url":null,"abstract":"<div><div>The electric field in pulsed bipolar plasma catalysis was characterized using the temperature functions and electric parameters of reactants (toluene and heptane), products, catalysts (La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub>/mullite), and dielectric barriers. An equivalent electrical circuit was established to demonstrate the behavior of plasma current phases. The optical emission spectra of discharge and Lissajous figures at various temperatures were used to identify dielectric barrier and surface discharges. The applied voltage composition was divided into three discharge phases, namely rapid pulse, reduced pulse and stretched release phases. Their coefficients were estimated to determine the phases’ roles in plasma catalysis. The formulas for applied voltage and discharge current in plasma catalysis were established in accordance with the concepts of the three phases. The electric field in the plasma catalysis was characterized using an established theoretical formula, various measurement techniques, and feasible approaches for estimating various electric field parameter values at different plasma catalytic temperatures were proposed.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114126"},"PeriodicalIF":3.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610160","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}

引用次数: 0

Tracing the early oxidation of Ni-based superalloys during hot-compression bonding 镍基高温合金在热压键合过程中的早期氧化

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-07 DOI: 10.1016/j.vacuum.2025.114237

Shaofei Ren , Xiaolong Bai , Sheng Liu , Bin Xu , Mingyue Sun

引用次数: 0

Enhancing the strength and ductility of rapidly-solidified 2196 Al-Li alloy through multi-stage ageing treatments 通过多级时效处理提高快速凝固2196铝锂合金的强度和塑性

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-03-07 DOI: 10.1016/j.vacuum.2025.114235

Shuaijiang Yan , Richu Wang , Chaoqun Peng , Zhiyong Cai , Xiang Peng , Ziming Li , Zixin Wu

{"title":"Enhancing the strength and ductility of rapidly-solidified 2196 Al-Li alloy through multi-stage ageing treatments","authors":"Shuaijiang Yan , Richu Wang , Chaoqun Peng , Zhiyong Cai , Xiang Peng , Ziming Li , Zixin Wu","doi":"10.1016/j.vacuum.2025.114235","DOIUrl":"10.1016/j.vacuum.2025.114235","url":null,"abstract":"<div><div>The precipitation behaviors and mechanical properties of rapidly-solidified 2196 Al-Li alloy were systematically investigated under multi-stage ageing treatments. The results reveal that T8 double ageing regime (DAT8, 3 % pre-stretching + 120 °C/12h + 170 °C/28h) enhances both ultimate tensile strength and ductility to 536.2 MPa and 5.3 %, respectively, by comparison with the T8 single-stage ageing treated sample (SAT8, 3 % pre-stretching + 170 °C/28h) of 514.8 MPa and 5 %. The enhancement in mechanical properties of the DAT8 treated alloy is ascribed to that the pretreatment (120 °C/12h) reduces the T<sub>1</sub> nucleation energy and δ′ phases promote the T<sub>1</sub> precipitation. The interrupted ageing treatment (IAT8, 170 °C/4h + 3 % pre-stretching + 65 °C/15 day + 170 °C/20h) facilitates θ′ phase precipitation and suppresses T<sub>1</sub> phase precipitation along variant 2 direction, but the elongation of the IAT8 alloy improves to 7.5 %. However, the re-solution and re-ageing treated (RST8, SAT8 + re-solution treatment + SAT8) alloy exhibits reduced tensile strength (479.5 MPa) but improved ductility (7.6 %). The modified precipitate strengthening model predicts yield strength of multi-stage aged alloys, with dislocation by-passing mechanism being more suitable for the present alloys. The present alloy has superior mechanical properties compared to other Al-Li alloys with comparable Li concentrations.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114235"},"PeriodicalIF":3.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610159","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}

引用次数: 0

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