IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-14 DOI: 10.1016/j.vacuum.2025.114411

You Li , Xiaolong Yang , Xuankai Dou , Shiying Zhou

{"title":"Research on the pressure capability of large sealing clearance symmetrical ferrofluid seal in gas sealing conditions","authors":"You Li , Xiaolong Yang , Xuankai Dou , Shiying Zhou","doi":"10.1016/j.vacuum.2025.114411","DOIUrl":"10.1016/j.vacuum.2025.114411","url":null,"abstract":"<div><div>Common ferrofluid seals utilize solely radial pole teeth (PT), which exhibit inadequate vacuum sealing performance and are susceptible to failure under large sealing clearance (SC) operating conditions. To improve the ability of the ferrofluid seal to seal gas under a large SC, this study designed a symmetrical ferrofluid seal and established an experimental platform. By combining theoretical analysis with experimental validation, the effects of key parameters including the ferrofluid volume, the SC size, the quantity of PT, the step height, and the PT position were investigated to determine their impact on the magnetic focusing capacity and pressure capability of the seal under large SC conditions. The results show that when the SC size and the quantity of PT are changed, the difference in the magnetic flux density (MFD) between the radial PT and axial PT has a significant impact on the pressure capability. Notably, the symmetrical ferrofluid seal pressure capability fluctuates around 0.5 atm stably, consistently surpassing the performance of common ferrofluid seals. This performance superiority becomes particularly significant under conditions of enlarged radial sealing clearance (RSC). These findings will provide a reference for improving the sealing performance of the ferrofluid seal under large SC.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114411"},"PeriodicalIF":3.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070424","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

Densification mechanism transition, microstructure evolution and mechanical behavior of EP741NP superalloy via hot-pressed sintering 热压烧结EP741NP高温合金致密化机制转变、显微组织演变及力学行为

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-14 DOI: 10.1016/j.vacuum.2025.114412

Xiaoyun Feng , Xinbing Yun , Haiping Bao , Fei Liang

{"title":"Densification mechanism transition, microstructure evolution and mechanical behavior of EP741NP superalloy via hot-pressed sintering","authors":"Xiaoyun Feng , Xinbing Yun , Haiping Bao , Fei Liang","doi":"10.1016/j.vacuum.2025.114412","DOIUrl":"10.1016/j.vacuum.2025.114412","url":null,"abstract":"<div><div>EP741NP Ni-based superalloy with remarkable mechanical properties is widely applied in the aerospace industry. Here, the effects of sintering temperature on the densification mechanism transition, microstructure and tensile properties of hot-pressed EP741NP Ni-based superalloy are revealed. The critical relative density, corresponding to densification mechanism transition, shifts from 0.71 to 0.80 as the sintering temperature increases from 1130 °C to 1230 °C, which is calculated by a proposed model considering the equality of localized contact pressure between particles and overall yield stress. The contribution of macroscopic plastic deformation to the overall densification increases as the sintering temperature rises due to the exacerbated material softening. The densification activation energy of the EP741NP superalloy is obtained as 377.07 kJ/mol. The initial dendritic structure, primary particle boundaries and voids are gradually eliminated as the sintering temperature rises, while the volume fraction of γ′ phase decreases due to the phase dissolution. Due to the balance between densification level and grain size, the sample hot pressed at 1180 °C exhibits the best synergy of strength and ductility at room temperature and 650 °C, accompanied by more characteristics of ductile fracture. Our work provides insights into the development of advanced Ni-based superalloys at elevated temperatures.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114412"},"PeriodicalIF":3.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070425","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

Ultrasonic vibration induced crystal to amorphous transformation of laser-cladded Fe-based amorphous composite coatings 超声振动诱导激光熔覆铁基非晶态复合涂层的晶向非晶态转变

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-14 DOI: 10.1016/j.vacuum.2025.114414

Haolun Song , Chunhuan Guo , Fengchun Jiang , Mingying Xiao , Mingxia Diao , Liyu Li

{"title":"Ultrasonic vibration induced crystal to amorphous transformation of laser-cladded Fe-based amorphous composite coatings","authors":"Haolun Song , Chunhuan Guo , Fengchun Jiang , Mingying Xiao , Mingxia Diao , Liyu Li","doi":"10.1016/j.vacuum.2025.114414","DOIUrl":"10.1016/j.vacuum.2025.114414","url":null,"abstract":"<div><div>Crystallization is often considered an unavoidable phenomenon during laser-cladded amorphous coatings, posing challenges for the development of fully amorphous materials with superior mechanical properties. To address this issue, a feasible approach was explored using ultrasonic vibration (UV)-assisted laser cladding to inhibit crystallization in Fe<sub>41.5</sub>Co<sub>12.2</sub>Cr<sub>7.4</sub>Mo<sub>37.3</sub>C<sub>0.3</sub>B<sub>0.5</sub>Y<sub>0.4</sub>Al<sub>0.4</sub> (at. %) amorphous composite coatings. By varying the ultrasonic amplitude, the microstructural evolution and property enhancement mechanisms were systematically investigated in these coatings. Our findings reveal that the amorphous content increases with the ultrasonic amplitude, highlighting the effectiveness of UV in promoting amorphous formation. The underlying mechanism involves two main factors: First, UV-induced changes in mixing entropy, enthalpy, and atomic radius differences disrupt the crystallization process. Second, the energy generated by UV induces a sound pressure gradient within the molten pool, promoting a more uniform elemental distribution and mitigating the formation of compositional inhomogeneities. Additionally, UV enhances the properties of the coatings though a synergistic effect of amorphous phase reinforcement. This study not only provides a comprehensive understanding of UV-induced microstructural transformations but also offers a promising strategy for fabricating high-performance amorphous coatings with tailored properties.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114414"},"PeriodicalIF":3.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083774","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

First-principles study on physical and hydrogen storage properties of XYH3 (X = K, Rb, Cs) perovskite hydrides XYH3 （X = K, Rb, Cs）钙钛矿氢化物物理和储氢性能的第一性原理研究

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-14 DOI: 10.1016/j.vacuum.2025.114415

Shijie Zhang , Ruijie Song , Yan Chen , Shanjun Chen , Nanlin Xu , Yifei Du , Weibin Zhang

{"title":"First-principles study on physical and hydrogen storage properties of XYH3 (X = K, Rb, Cs) perovskite hydrides","authors":"Shijie Zhang , Ruijie Song , Yan Chen , Shanjun Chen , Nanlin Xu , Yifei Du , Weibin Zhang","doi":"10.1016/j.vacuum.2025.114415","DOIUrl":"10.1016/j.vacuum.2025.114415","url":null,"abstract":"<div><div>In this study, we have employed the density functional theory to analyze the hydrogen storage capacities, structural, mechanical, photoelectric, dynamical and thermodynamic properties of XYH<sub>3</sub> (X = K, Rb, Cs) compounds for the first time. The calculated formation energies, elastic constants, and phonon dispersion curves of XYH<sub>3</sub> show that they have thermodynamical, mechanical, and dynamical stabilities. Both the Cauchy pressure and the B/G ratio indicate brittle behaviors, and their stress-strain curves are also analyzed. Furthermore, it is found that they are all anisotropic compounds with ionic bonds. The band structures indicate that the XYH<sub>3</sub> compounds are metallic. Their optical properties reveal strong transmission in the blue-green wavelength band and a high refractive index in the visible range. Thermodynamic properties, including entropy, enthalpy, heat capacity and free energy as a function of temperature are studied. The desorption temperatures of different dehydrogenation paths are calculated, and the optimal desorption temperatures of KYH<sub>3</sub>, RbYH<sub>3</sub>, and CsYH<sub>3</sub> are 332, 317, and 295 K, respectively. The adsorption/desorption energies of hydrogen on the surface (100) of these materials are also studied. We expect this study will provide a valuable reference for further research on XYH<sub>3</sub> compounds.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114415"},"PeriodicalIF":3.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083858","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

High-vacuum carbosilicothermic reduction of manganese in thin films 薄膜中锰的高真空碳硅热还原

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-13 DOI: 10.1016/j.vacuum.2025.114398

Tatyana A. Andryushchenko , Sergey A. Lyaschenko , Ivan V. Nemtsev , Anna V. Lukyanenko , Yevgeny V. Tomashevich , Sergey N. Varnakov , Sergei G. Ovchinnikov

{"title":"High-vacuum carbosilicothermic reduction of manganese in thin films","authors":"Tatyana A. Andryushchenko , Sergey A. Lyaschenko , Ivan V. Nemtsev , Anna V. Lukyanenko , Yevgeny V. Tomashevich , Sergey N. Varnakov , Sergei G. Ovchinnikov","doi":"10.1016/j.vacuum.2025.114398","DOIUrl":"10.1016/j.vacuum.2025.114398","url":null,"abstract":"<div><div>High-vacuum carbosilicothermic reduction of MnO<sub>x</sub> thin films on Si(100) substrates was investigated in the temperature range of 200–700 °C using in-situ Auger electron spectroscopy along with mass spectroscopy and ex-situ X-ray photoelectron spectroscopy. Carbothermic reduction of manganese, accompanied by the CO evolution, occurs over the entire temperature range. When heated above 500 °C, silicothermic reduction and formation of manganese silicides are observed. The efficiency of carbothermic reduction of Mn in thin films turned out to be higher at C:Mn = 1:10 than at C:Mn = 1:5. Carbon in the samples is assumed to be present in two forms: as amorphous carbon in a mixture with oxygen and manganese, and as individual, larger particles with a graphite structure. The particle size depends on the power of the magnetron source and influences the carbon coalescence activity, which competes with the carbothermic reduction process. The efficiency of silicothermic reduction on the film surface depends on the initial carbon concentration.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114398"},"PeriodicalIF":3.8,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089651","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

Microstructure and mechanical properties of a novel AlSiFeNiMn alloy fabricated by laser powder bed fusion 激光粉末床熔合制备新型AlSiFeNiMn合金的显微组织和力学性能

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-12 DOI: 10.1016/j.vacuum.2025.114399

Tiankuang Ding , Xiaohui Liu , Chenghao Liu , Changyang Fang , Hao Qiu , Yunzhong Liu

{"title":"Microstructure and mechanical properties of a novel AlSiFeNiMn alloy fabricated by laser powder bed fusion","authors":"Tiankuang Ding , Xiaohui Liu , Chenghao Liu , Changyang Fang , Hao Qiu , Yunzhong Liu","doi":"10.1016/j.vacuum.2025.114399","DOIUrl":"10.1016/j.vacuum.2025.114399","url":null,"abstract":"<div><div>Al-Si alloys fabricated by laser powder bed fusion (LPBF) exhibit excellent comprehensive mechanical properties. However, the application of LPBF-ed Al-Si alloys was limited by their poor high temperature properties. To meet the requirement of automotive and aerospace industries, a novel Al-Si alloy needs to be developed. In this study, a new type of LPBF-ed AlSiFeNiMn alloy was prepared, demonstrating excellent mechanical properties at both room and elevated temperatures. AlSiFeNiMn alloy samples were fabricated by LPBF. The melting channel and cellular structures were characterized. Evenly distributed intermetallic compounds α-Al(FeMn)Si and Al<sub>3</sub>Ni were present in the as-built samples, and the accumulation of α-Al(FeMn)Si in secondary cells was analyzed. The superior tensile properties of LPBF-ed AlSiFeNiMn alloy were confirmed (UTS 513 MPa, EI 8 % at 25 °C; UTS 248 MPa, EI 14 % at 300 °C; UTS 153 MPa, EI 15 % at 400 °C). The increase in tensile strength is primarily attributed by the introduction of finely dispersed phases α-Al(FeMn)Si and Al<sub>3</sub>Ni, while the grain size of as-built sample shows no obvious refinement compared to those of existing LPBF-ed Al-Si alloys. Intermetallic compounds with excellent thermal stability and hardness effectively prohibit the slide of dislocations at 400 °C, which significantly improve the mechanical properties of the AlSiFeNiMn alloy.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114399"},"PeriodicalIF":3.8,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068381","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

Preparation of high hardness and high fracture toughness Si3N4 ceramics by combining in-situ nitriding and hot-press sintering 原位氮化与热压烧结相结合制备高硬度、高断裂韧性Si3N4陶瓷

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-11 DOI: 10.1016/j.vacuum.2025.114402

Shiao Wu , Yang Li , Yueming Li , Fuyuan Zheng , Zhongyi Zhao , Xiangqing Kong , Guorui Zhao

{"title":"Preparation of high hardness and high fracture toughness Si3N4 ceramics by combining in-situ nitriding and hot-press sintering","authors":"Shiao Wu , Yang Li , Yueming Li , Fuyuan Zheng , Zhongyi Zhao , Xiangqing Kong , Guorui Zhao","doi":"10.1016/j.vacuum.2025.114402","DOIUrl":"10.1016/j.vacuum.2025.114402","url":null,"abstract":"<div><div>Preparation Si<sub>3</sub>N<sub>4</sub> ceramics with high hardness and high fracture toughness is a challenge. In this work, Si<sub>3</sub>N<sub>4</sub> ceramics with high hardness (18.35 ± 0.40 GPa) and high fracture toughness (8.54 ± 0.26 MPa m<sup>1/2</sup>) were obtained by in-situ nitriding of Si and Y powders and hot-press sintering. By controlling Y content, Si<sub>3</sub>N<sub>4</sub> powders with different α-Si<sub>3</sub>N<sub>4</sub> ratios were obtained, which in turn regulated grain size and morphology of Si<sub>3</sub>N<sub>4</sub> ceramics after sintering. Addition of Y introduces Y-Si-O-N crystalline phase into nitrided powder, which transitions to Y<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> during subsequent sintering. Y<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> phase reduces bulk hardness but introduces residual stresses at interface, promotes grain elongation, and improves fracture toughness through crack bridging, stretching, and crack deflection mechanisms. In addition, atomic-scale microstructural analysis reveals coherent interfaces were formed between both Si<sub>3</sub>N<sub>4</sub>/SiO<sub>2</sub>/Y<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> as well as Si<sub>3</sub>N<sub>4</sub>/Si<sub>2</sub>N<sub>2</sub>O, with crystallographic orientation relationships of (100) Si<sub>3</sub>N<sub>4</sub>//(100) SiO<sub>2</sub>//(−111) Y<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> and [010] Si<sub>3</sub>N<sub>4</sub>//[001] SiO<sub>2</sub>//[12–1] Y<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> as well as (100) Si<sub>3</sub>N<sub>4</sub>//(020) Si<sub>2</sub>N<sub>2</sub>O and [010] Si<sub>3</sub>N<sub>4</sub>//[−102] Si<sub>2</sub>N<sub>2</sub>O. These in-situ generated coherent interfaces significantly enhance mechanical properties and reliability of samples, ensuring both high hardness and high fracture toughness.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114402"},"PeriodicalIF":3.8,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068378","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

Preparation of noble metal nanoparticles modified hollow SnO2 dodecahedrons for highly selective hydrogen detection

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-11 DOI: 10.1016/j.vacuum.2025.114407

Chen Chen , Junhai Wang , Yu Sun , Areeje Fatima , Jiarui Huang

{"title":"Preparation of noble metal nanoparticles modified hollow SnO2 dodecahedrons for highly selective hydrogen detection","authors":"Chen Chen , Junhai Wang , Yu Sun , Areeje Fatima , Jiarui Huang","doi":"10.1016/j.vacuum.2025.114407","DOIUrl":"10.1016/j.vacuum.2025.114407","url":null,"abstract":"<div><div>To develop high-responsive and selective sensors for H<sub>2</sub> detection at low concentration is on demand. Here, ammonium phosphotungstate hydrate dodecahedrons were used as hard templates to prepare hollow SnO<sub>2</sub> dodecahedron with a large specific surface area. Then, Pd/SnO<sub>2</sub>, Ag/SnO<sub>2</sub> and Pt/SnO<sub>2</sub> hollow dodecahedrons were prepared via a liquid-phase reduction method by uniformly decorating the SnO<sub>2</sub> hollow dodecahedrons with finely dispersed Pd, Ag and Pt nanoparticles, respectively. The morphology, microstructure, and gas-sensing characteristics of the prepared sensing materials were analyzed. Compared with the SnO<sub>2</sub>, Ag/SnO<sub>2</sub> and Pt/SnO<sub>2</sub> hollow dodecahedron sensors, the Pd/SnO<sub>2</sub> hollow dodecahedron sensor exhibited a better response value and linearity to 0.1 % H<sub>2</sub> at the optimal operating temperature (160 °C), and a significant response (2.6) and shorter response/recovery time (15 s/9 s) to 0.1 % H<sub>2</sub> even at low operating temperature (80 °C). Moreover, this sensor exhibits high selectivity and long-term stability for H<sub>2</sub> at low operating temperatures (80 °C). The outstanding performance of this sensor is due to its exceptional microstructure, namely the hollow dodecahedron structure with a high specific surface area, and the catalytic properties of Pd nanoparticles, as well as the synergistic interplay between crystal structure and morphology.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114407"},"PeriodicalIF":3.8,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943028","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

Vacuum separation behavior of polymorphic metal in waste Li-ion battery Al slag

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-11 DOI: 10.1016/j.vacuum.2025.114406

Biao Liang , Zhe Gao , Shaoxiong Li , Weichen Yang , Linxing Deng , Yuan Tao , Xiangfeng Kong , Bin Yang , Dachun Liu

{"title":"Vacuum separation behavior of polymorphic metal in waste Li-ion battery Al slag","authors":"Biao Liang , Zhe Gao , Shaoxiong Li , Weichen Yang , Linxing Deng , Yuan Tao , Xiangfeng Kong , Bin Yang , Dachun Liu","doi":"10.1016/j.vacuum.2025.114406","DOIUrl":"10.1016/j.vacuum.2025.114406","url":null,"abstract":"<div><div>Waste Li-ion battery Al slag (WLAS) is a substance that combines the characteristics of valuable secondary resources and hazardous solid waste. Traditionally chemical conversion treatments pose potential hazards to ecosystems, resulting in lower resource utilization rates and higher energy consumption. In this investigation, vacuum metallurgical techniques were strategically employed, leveraging the distinct volatilization and melting behaviors of constituent elements, to systematically examine the gas-phase separation theory of volatile metallic components and the vacuum melting behavior of refractory metals in WLAS. Thermodynamic analysis encompassing phase transition Gibbs free energy (ΔG), saturated vapor pressure, and maximum volatilization rates substantiated the technical feasibility of Al purification and impurity metal separation through vacuum processing. Experimental findings demonstrated that Al formed a stable metallic melt, with 98 % purity Al being directly recovered from WLAS at 1550 K. Conversely, Zn, Na, Ga, and Pb underwent complete solid-gas phase transitions, enabling their effective separation through volatilization. Fe, Cu, and Ni, exhibiting similar metallurgical behavior to Al, were concentrated in the residual phase through liquid-liquid phase separation. This promising approach not only enabled the environmentally safe disposal of WLAS but also ensured the effective recovery of sustainable Al resources.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114406"},"PeriodicalIF":3.8,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943026","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

Structure and formation mechanism of morphological defects with stacking faults in thick 4H-SiC epilayers 厚4H-SiC层中层错形态缺陷的结构及形成机制

IF 3.8 2区材料科学

Vacuum Pub Date : 2025-05-11 DOI: 10.1016/j.vacuum.2025.114405

Pin Wang , Yong Li , Lei Xu , Yifei Li , Pengxiang Hou , Jiulong Wang , Jing Wang , Le Yu , Zheyang Li , Rui Jin

{"title":"Structure and formation mechanism of morphological defects with stacking faults in thick 4H-SiC epilayers","authors":"Pin Wang , Yong Li , Lei Xu , Yifei Li , Pengxiang Hou , Jiulong Wang , Jing Wang , Le Yu , Zheyang Li , Rui Jin","doi":"10.1016/j.vacuum.2025.114405","DOIUrl":"10.1016/j.vacuum.2025.114405","url":null,"abstract":"<div><div>Morphological defects with stacking faults (SFs) not only affect the uniformity of the epilayer surface, but also create leakage paths for SiC power devices, severely limiting device performance. This study sheds light on the structure and formation mechanism of a triangular defect, characterized by two groove sides and one step bunching side, with a SF incorporated within defect. Peak-valley-peak morphological structures are observed on grooves and step bunching, in which the maximum depths are 2.6 μm and 5.5 nm, respectively. Photoluminescence from multiple triangular defects show Frank type SFs with emission peaks of 457 nm, 530 nm, and 553 nm. In comparison, line-shaped defects without groove features exhibit simpler SF configurations. Combined molten KOH etching, micro-Raman spectroscopy and scanning transmission electron microscopy reveal higher strain and enhanced localized lattice distortion at the 4H/SF boundary in triangular defects than in line-shaped defects. The origin of groove morphology could be attributed to the preferential etching of hydrogen in the high strain regions.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"239 ","pages":"Article 114405"},"PeriodicalIF":3.8,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068928","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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