Vacuum最新文献

{"title":"MoS2 stabilize Ti3C2 MXene for excellent catalytic effect of thermal decomposition of ammonium perchlorate","authors":"Zhehong Lu ,&nbsp;Jingyi Li ,&nbsp;Binxin Li ,&nbsp;Ruixuan Yuan ,&nbsp;Guolin Cao ,&nbsp;Shaoliang Guan ,&nbsp;Wei Jiang ,&nbsp;Jie Zhu","doi":"10.1016/j.vacuum.2024.113812","DOIUrl":"10.1016/j.vacuum.2024.113812","url":null,"abstract":"<div><div>Ammonium perchlorate (AP), the most widely used oxidizer in energetic materials, is crucial for studying catalytic thermal decomposition. Newly discovered Ti₃C₂ MXene and MoS₂ demonstrating promising prospects in the field of the pyrolysis catalyst in AP. In this study, we employed a hydrothermal method to anchor nano-sized MoS₂ in situ on the surface of Ti₃C₂ MXene, leading to the fabrication of MoS₂-Ti₃C₂ nanocomposites. Various characterizations indicated that MoS₂ was attached to the surface and edges of Ti₃C₂, thereby enhancing the stability and conductivity. Results revealed that upon the addition of 4 wt% MoS₂-Ti₃C₂, the low-temperature decomposition peak of AP reduced from 331.2 °C to 296.6 °C, while the high-temperature decomposition peak advanced from 427.5 °C to 387.1 °C, showing a superior catalytic effect compared to the individual MoS₂ or Ti₃C₂. Additionally, the catalytic mechanism of MoS₂-Ti₃C₂ on the thermal decomposition of AP may involve enhanced electrical conductivity, facilitating rapid proton transfer (H⁺), accelerated redox reactions, prompt release of gas products, and thereby expediting the progression of the decomposition reaction. Consequently, it can be anticipated that anchoring MoS₂ on the surface of Ti₃C₂ represents an effective strategy for enhancing the catalytic activity of Ti₃C₂ MXene towards the thermal decomposition of AP.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113812"},"PeriodicalIF":3.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659415","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":"Atomic layer deposition of tin monosulfide thin film using Sn(acac)2 and H2S","authors":"Dowwook Lee ,&nbsp;Hyeongtag Jeon","doi":"10.1016/j.vacuum.2024.113808","DOIUrl":"10.1016/j.vacuum.2024.113808","url":null,"abstract":"<div><div>In this study, we deposited tin monosulfide (SnS) thin film using Tin(II) 2,4-pentanedionate [Sn(acac)2] precursor and hydrogen sulfide (H2S) reactant. And we performed post annealing to improve the crystallinity of SnS thin films. The process window was 130 °C–150 °C, and the growth rate was 0.34 Å/cycle. To investigate crystallinity and the phase of SnS thin films, grazing incidence x-ray diffraction (GI-XRD) and Raman spectroscopy were performed. SnS thin films showed a single orthorhombic phase after annealing. In addition, transmission electron microscopy (TEM) was utilized to confirm the two-dimensional (2D) layered structure of SnS thin films. Post-annealed SnS thin film clearly showed a 2D layered structure. X-ray photoelectron spectroscopy (XPS) was performed to confirm the bonding state of the thin film. The results indicated that the SnS thin film only shows binding energies corresponding to the oxidation states of Sn²⁺ in the Sn 3d spectra and S^2- in the S 2p spectra. Ultraviolet–visible (UV–vis) spectroscopy and ultraviolet photoelectron spectroscopy (UPS) were performed to confirm the optical properties and to calculate the band structure of the thin film. All of SnS thin film showed a p-type characteristic. The post-annealed SnS thin films exhibited better electric properties, confirmed by Hall measurement.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113808"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659417","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":"Experimental and zero-dimensional simulation study of an embedded bismuth LaB6 hollow cathode","authors":"Dongsheng Cai ,&nbsp;Pingyang Wang ,&nbsp;Zhiwei Hua","doi":"10.1016/j.vacuum.2024.113807","DOIUrl":"10.1016/j.vacuum.2024.113807","url":null,"abstract":"<div><div>Experiments and zero-dimensional simulation were conducted to evaluate the discharge performance of an embedded bismuth LaB₆ hollow cathode. The experimental results demonstrate that the embedded bismuth hollow cathode can operate in diode mode without any external heating, with a mass flow rate of approximately 0.21 mg/s. In Keeper-cathode mode, the discharge voltage for bismuth was slightly lower than that of xenon and exhibited strong stability, with a maximum discharge variation of less than 0.5 V at a discharge current of 2 A. The simulation results showed that at the same mass flow rate, the electron and ion densities in the insert region of the bismuth hollow cathode were higher than those of xenon, whereas the opposite was true for the orifice region. Notably, at discharge currents below 4 A, the power deposition of bismuth in both the insert and orifice regions was lower than that of xenon, indicating reduced erosion.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113807"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659329","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":"Effect of substrate type on structural and electrochemical performance of vertical graphene nanosheets deposited by HWP-CVD","authors":"Jiali Chen ,&nbsp;Yanyan Wang ,&nbsp;Peiyu Ji ,&nbsp;Lanjian Zhuge ,&nbsp;Xuemei Wu","doi":"10.1016/j.vacuum.2024.113800","DOIUrl":"10.1016/j.vacuum.2024.113800","url":null,"abstract":"<div><div>Vertical graphene nanosheets (VGs) were synthesized on Cu, Ti, Si, and C substrates by helicon wave plasma chemical vapor deposition (HWP-CVD) method using CH₄/Ar as precursors. The obtained samples formed vertical orientation structures of nanosheets-graphene as the scanning electron microscopy and TEM images indicated. Specifically, the VGs grown on Cu substrate exhibit a parallel arrangement with a wall spacing of approximately 450 nm. This structural characteristic facilitates efficient ion exchange channels and promotes low resistance for electron transport. The effect of substrate type on the growth mechanism of VGs was discussed. The relationship between the microstructure and electrochemical performance of the VGs grown on different substrates was investigated. The charge transfer resistance of the VGs/Cu is 20.75 Ω, and the value of VGs/Ti, VGs/C and VGs/Si are 23.51 Ω, 33.76 Ω and 66.40 Ω, respectively. The robust vertical orientation structure of VGs holds promise for various applications, including catalyst support in fuel cells, conductive electrodes in photovoltaic cells, and energy storage devices like lithium-ion batteries and supercapacitors. This structural characteristic plays a pivotal role in advancing the development of next-generation energy storage technologies.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113800"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659509","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":"Thermophysical properties of AlxCoCrCuFeNi high entropy alloys","authors":"W.H. Li ,&nbsp;X. Weng ,&nbsp;L.J. Meng ,&nbsp;J. Chen ,&nbsp;L. Hu ,&nbsp;D.L. Geng ,&nbsp;W.L. Wang","doi":"10.1016/j.vacuum.2024.113770","DOIUrl":"10.1016/j.vacuum.2024.113770","url":null,"abstract":"<div><div>The Al_<em>x</em>CoCrCuFeNi (<em>x</em> = 0.25, 0.5, 1, 2) high entropy alloys (HEAs) were prepared by arc melting and spray casting techniques. Their microstructures, hardness, and thermophysical properties such as fusion enthalpy, entropy, thermal diffusion coefficients, thermal expansion coefficients, were investigated. XRD results indicated that Al_<em>x</em>CoCrCuFeNi (<em>x</em> = 0.25 and 0.5) alloys were composed of a high-entropy FCC phase and Cu-rich nanophase. As the Al content increased to 1 and 2, the phase structures included the AlNi-rich B2 phase, FeCr-rich A2 phase and Cu-rich nanophase. With the increased Al content, the microstructures of Al_<em>x</em>CoCrCuFeNi HEAs transitioned from coarse dendrites to petal-like dendrites, and the grains were continuously refined. Moreover, the Al additions reduced the density whereas increased the Vickers hardness of the alloys. The maximum hardness observed in Al₂CoCrCuFeNi HEA was approximately 2.4 times greater than that of the Al_0.25CoCrCuFeNi HEA. The thermal diffusion coefficients of alloys initially increased and subsequently decreased as the temperature elevated. The phase transformation induced by Al content was an effective method for rapidly homogenizing the internal temperature of alloys. Furthermore, the crystal structure, elemental segregation, lattice distortion, enthalpy and entropy of fusion, and lattice vibration frequency all mutually affected the thermal diffusion and expansion coefficients of Al_<em>x</em>CoCrCuFeNi HEAs.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113770"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659507","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":"Characterization of optical depth for laser produced plasma extreme ultraviolet source","authors":"Tianze Wang ,&nbsp;Zhenlin Hu ,&nbsp;Liang He ,&nbsp;Nan Lin ,&nbsp;Yuxin Leng ,&nbsp;Weibiao Chen","doi":"10.1016/j.vacuum.2024.113805","DOIUrl":"10.1016/j.vacuum.2024.113805","url":null,"abstract":"<div><div>This study investigates the emission mechanism of laser-produced plasma extreme ultraviolet source (LPP-EUV). In the experiment, the EUV radiation is generated by a 1064 nm laser interacting with slab Sn target. The EUV emission is characterized by EUV energy monitors and an EUV spectrometer. The dependency of CE on laser intensity and plasma relative optical depth is explored by a plasma emission-absorption layer model. The dependency is confirmed by an optical interferometry measurement of plasma electron density for the first time. Our work provides a method for characterizing and optimizing the optical depth of laser driven EUV source.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113805"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659454","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":"Quasi-in-situ observations of microstructural evolution during cyclic deformation of a Mg-Zn-Ca alloy","authors":"G.H. Cao ,&nbsp;H. Wang ,&nbsp;C. Qiu ,&nbsp;F.S. Meng ,&nbsp;Z.J. Deng ,&nbsp;D.T. Zhang ,&nbsp;D.L. Chen","doi":"10.1016/j.vacuum.2024.113804","DOIUrl":"10.1016/j.vacuum.2024.113804","url":null,"abstract":"<div><div>Quasi-in-situ electron backscatter diffraction (EBSD) was employed to investigate the microstructural evolution of a homogenized coarse-grained Mg-1.2Zn-0.1Ca alloy during cyclic deformation at a strain amplitude of 0.8 %. The random orientations of grains along with the soft state of the alloy resulted in symmetrical hysteresis loops and cyclic hardening. Besides the occurrence of twinning-detwinning, basal &lt;a&gt;/pyramidal II &lt;c+a&gt; and pyramidal I &lt;a&gt; slip systems were primarily activated. Grain boundaries with a higher misorientation angle of &gt;35° served as preferential sites for strain localization.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113804"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593415","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":"Editorial Board and Vacuum units","authors":"","doi":"10.1016/S0042-207X(24)00832-7","DOIUrl":"10.1016/S0042-207X(24)00832-7","url":null,"abstract":"","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"230 ","pages":"Article 113786"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587365","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":"Effects of translation misalignment on ion optics with slit apertures","authors":"Zhi Yang ,&nbsp;Honghui Guo ,&nbsp;Hongtao Liu ,&nbsp;Jinwei Bai ,&nbsp;Yong Cao","doi":"10.1016/j.vacuum.2024.113793","DOIUrl":"10.1016/j.vacuum.2024.113793","url":null,"abstract":"<div><div>For ion thrusters, the deflection of the ion beam caused by the relative translation of the grids is one of the primary factors limiting the erosion lifetime of the ion optical system. A two-dimensional (2D) simulation package of the ion optic system is developed to investigate the ion sputtering corrosion due to grid translation misalignment. For benchmark cases, the 2D simulation package shows a reasonable consistency compared to the experimental method in ion beam deflection angle and drain-to-beam current ratio, indicating the effectiveness of the simulation package. The deviation between the simulated deflection angle and the experimental value is within 8.86%. Furthermore, this 2D package is employed to analyze the variation patterns of ion beam, ion collection, and the distribution of ion sputtering rates caused by grid translation. The simulation results indicate that the ion beam deflection occurs in the direction opposite to grid translation. The number of ions collected at different positions on the acceleration grid shows different tendencies. Only the upstream surface <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>y−</mi></mrow></msub></math></span> and the aperture surface <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>x+</mi></mrow></msub></math></span> will be subjected to energetic ion impingement. The sputtering of energetic ions on these two surfaces becomes the dominant factor limiting the grid’s ion corrosion lifetime when the grid translation is significant. The sputtering rate of energetic ions can exceed that of charge exchange (CEX) ions by more than 10 times. The proportion of the region where energetic ions contribute to sputtering expands with increasing grid misalignment, reaching up to 52.5% on surface <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>x+</mi></mrow></msub></math></span>. Additionally, the downstream surface <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>y+</mi></mrow></msub></math></span> and the aperture surface <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>x−</mi></mrow></msub></math></span> are only subjected to CEX ion sputtering regardless of grid translation. Moreover, the CEX ion sputtering regions on surfaces <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>x−</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>x+</mi></mrow></msub></math></span> expand as the grid misalignment distance increases. The peak in the ion sputtering rate distribution profile on surface <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>y+</mi></mrow></msub></math></span> becomes more prominent due to grid translation, with the sputtering rate at the peak position reaching approximately 1.65 times that of the surrounding lower-rate regions. The analysis of the electric field indicates that local electric field variations caused by grid misalignment are the underlying reason for the ion erosion characteristics.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113793"},"PeriodicalIF":3.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659408","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":"Microstructure evolution behavior and SERS properties of self-grown Ag/Ag-Nb nano-island films sputtered on flexible substrates","authors":"Haitao Zheng ,&nbsp;Mingshuai Shen ,&nbsp;Zunyan Xie ,&nbsp;Ziyi Li ,&nbsp;Mengran Zhang ,&nbsp;Haoliang Sun","doi":"10.1016/j.vacuum.2024.113802","DOIUrl":"10.1016/j.vacuum.2024.113802","url":null,"abstract":"<div><div>Ag-Nb alloy films with varying Nb content were deposited on flexible polyimide substrates by the magnetron sputtering metho. The results show that dense and monodisperse Ag nano-islands were self-grown on the surfaces of as-deposited Ag-31.1 at% Nb alloy films. FDTD simulations revealed that the local electric field strength is closely related to the covering Ag layer, size and spacing of self-grown nano-islands. A 166-nm Ag-31.1 % Nb alloy film covered with 15-nm Ag layer served as the SERS substrate presented excellent and stable SERS performance and can detect 5 × 10⁻¹⁴ mol/L R6G solution. The preparation method of Ag nano-island/alloy films offers a novel approach for producing reproducible and highly sensitive SERS substrates.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"231 ","pages":"Article 113802"},"PeriodicalIF":3.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586935","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}