Article
Materials Science, Multidisciplinary
Aleksandr Klimov, Ilya Bakeev, Efim Oks, Aleksey Zenin
Summary: This study investigates the electron beam sintering of multilayer ZrO2-Al2O3 composite ceramics at forevacuum pressure and determines the optimal layer thickness to minimize temperature drop. By considering the thermophysical parameters of the sintered materials and forming a layered structure, the temperature gradient can be reduced.
Article
Materials Science, Ceramics
Venkata Keerti Vardhan Pasagada, Ni Yang, Chengying Xu
Summary: This paper presents an effort to process ultra-high temperature ceramics (UHTCs) using Electron Beam Sintering (EBS) method. The differences between EBS and traditional processing methods are analyzed. Experimental results demonstrate the feasibility of EBS process for producing dense and defect-free UHTC components with unique grain arrangement.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Ceramics
A. S. Klimov, I. Yu Bakeev, E. M. Oks, A. A. Zenin
Summary: The results of pressureless electron beam sintering of Al2O3/Ti composite in the fore-vacuum range of pressure were investigated. A novel electron source was used to irradiate the surface of the compacted composite with a focused electron beam at a pressure of 30 Pa. The effects of different irradiation regimes and compact size on the properties of the sintered material were studied, including hardness, density, and porosity. The temperature variation across the sample thickness was also measured and calculated. It was found that the sintering process produced three regions with different porosity and hardness, with the middle region reaching a microhardness of 29 GPa. The formation of these regions was attributed to the low thermal conductivity of the alumina ceramic component of the composite. Sintering regimes that resulted in low porosity samples were identified.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
D. A. Permin, S. V. Egorov, A. V. Belyaev, S. S. Balabanov, V. A. Koshkin, M. S. Boldin, A. V. Novikova, O. V. Timofeev, I. V. Ladenkov
Summary: A method for preparing dense Y2O3-MgO composite ceramics by microwave sintering was developed. The initial powders were obtained using glycine-nitrate self-propagating high-temperature synthesis (SHS) with different oxidant-to-fuel ratios. The density and IR-transmission of the microwave sintered Y2O3-MgO ceramics increased with the dispersity of the SHS powders and reached maximum values for the powder prepared with a 20% fuel excess. The sintering behavior of Y2O3-MgO compacts was investigated using optical dilatometry and conductivity measurements. Significant microwave radiation power surges at temperatures of 900-1000 degrees C, caused by the decomposition of magnesium carbonate, were observed. By matching the conditions for powder synthesis and sintering modes, a transmission of 78% at a wavelength of 6 μm was achieved for the composite ceramics at a maximum processing temperature of 1500 degrees C.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Yuze Xue, Le Xin, Mingwei Zhang, Panpan Lyu, Luchao Ren, Jiwei Zhai
Summary: Double sintering effectively improves the performance of Ba0.5Sr0.5TiO3-ZnAl2O4 composite ceramics, resulting in higher density, more uniform grain size distribution, and reduced dielectric permittivity, oxygen vacancy content, and grain boundary resistance. The optimum dielectric tunability and Q value are 23.4% and 276, respectively. Double sintering is an effective strategy for adjusting the properties of composite ceramics.
CERAMICS INTERNATIONAL
(2023)
Article
Engineering, Environmental
Rupita Ghosh, Shazia Shaikh, Sneha Gupta, Shreya Mehrotra, Ashok Kumar
Summary: In this study, Mg-doped calcium silicate ceramic diopside was used as a ceramic matrix material, and rare earth lanthanum phosphate was introduced as a reinforcement to improve machinability. The composites were sintered at different temperatures and conditions, and the double sintered composites showed the highest densification and mechanical properties. The optimized ceramic composites exhibited machinability, bioactivity, biocompatibility, and osteoconductivity.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Ceramics
Xi Wang, Shicheng Zhou, Kaiyang Liu, Shan Deng, Yaqi Xiao, Xiuli Chen, Huanfu Zhou
Summary: Extensive research has been conducted on microwave dielectric materials for their application in 5G and 6G communication technologies. This study broadened the sintering temperature range of MT-C ceramics using a composite of CeO2 and Mg2TiO4 ceramics, and stabilized their microwave dielectric performance. The prepared MT-C ceramics exhibited low loss and uniform density, making them suitable for industrial applications in the field of communication.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Physical
S. A. Nikolaeva, E. N. Lysenko, E. V. Nikolaev, V. A. Vlasov, A. P. Surzhikov
Summary: This study investigated the structural and electromagnetic properties of lithium-titanium-zinc ferrite ceramics with different content of ZrO2 additive. The addition of ZrO2 reduced the average grain size and ferrite with 1% ZrO2 content exhibited high density and high electrical resistivity.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Ceramics
Xinming Ren, Beiyue Ma, Gaofeng Fu, Fan Qian, Guoqi Liu, Jingkun Yu, Yawei Li
Summary: Utilizing magnesite tailings and silicon kerf waste, MgO-Mg2SiO4 composite ceramics were prepared through solid-state reaction synthesis. The as-prepared ceramics showed improved density and strength, and reduced thermal conductivity, providing a potential reutilization strategy for waste materials.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Ceramics
Liya Li, Jinxing Gao, Guanglei Chang, Jinghua Mu, Enxia Xu, Xinhong Liu, Juan Yan, Huoxiang Zhou, Liguo Zhang
Summary: This study investigates the effect of 13-SiAlON content on the sintering, phase, microstructure, and bacteriostatic properties of 13-SiAlON-Si3N4 composite ceramics. The results show that with an increase in 13-SiAlON content, the sintering becomes denser, the porosity decreases, and the ceramic exhibits optimal properties at 30 wt% 13-SiAlON content.
CERAMICS INTERNATIONAL
(2022)
Article
Crystallography
Jiuyuan Han, Mengjiao Chi, Liu Yang, Bing Liu, Minmin Mao, Hadi Barzegar Bafrooei, Zhongyan Ma, Yingjie Ren, Feng Shi, Ehsan Taheri-Nassaj, Dawei Wang, Kaixin Song
Summary: Dense composites of NaCl-NZO and HB-NZO-NaCl were prepared using the cold sintering process. The resulting ceramic composites showed promising characteristics with comparable permeability and dielectric constants suitable for radio-frequency electronic device applications. These findings indicate potential applications in wireless communication.
Article
Materials Science, Ceramics
Jiangao Liu, Yang Li, Changgui Cheng, Wei Li, Xufeng Qin
Summary: The effect of temperature on the microstructure and mechanical properties of SiC-TiB2 composite ceramics was investigated using solid-phase spark plasma sintering (SPS). The experimental results showed that the addition of TiB2 can significantly improve the mechanical properties of SiC-TiB2 composite ceramics, while higher sintering temperature leads to a decrease in mechanical properties. The best mechanical properties were obtained at 1750 degrees C.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
Ievgen Solodkyi, Iurii Bogomol, Petro Loboda
Summary: A high-speed electron beam sintering technique was proposed for producing fully dense submicron-grained WC-8Co hardmetals in this study. By controlling thermal stresses during local electron beam heating at different rotation speeds, the sintering time of porous compacts to full density was shown to be less than 150 s, with well-sintered material obtained.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Yong Guo, Junlang Tan, Jingchang Zhao
Summary: In this study, CCTO/CTO/TiO2 composite ceramics were fabricated by an in situ route. It was found that excessive CTO and TiO2 significantly reduced the grain boundary resistance and width, resulting in a colossal dielectric constant.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Materials Science, Multidisciplinary
Sushree Sefali Mishra, Swapan Kumar Karak, Debasis Chaira
Summary: In this study, Si3N4-Mo and Si3N4-Mo-Si cermets were fabricated using powder metallurgy, and their phase evolution, microstructure, and mechanical properties were analyzed. The effects of additives and reinforcements on the performance of the cermets were significant, with S75M25 cermet exhibiting the highest hardness.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Aleksandr Klimov, Ilya Bakeev, Efim Oks, Aleksey Zenin
Summary: This study investigates the electron beam sintering of multilayer ZrO2-Al2O3 composite ceramics at forevacuum pressure and determines the optimal layer thickness to minimize temperature drop. By considering the thermophysical parameters of the sintered materials and forming a layered structure, the temperature gradient can be reduced.
Article
Physics, Fluids & Plasmas
I. Yu Bakeev, A. S. Klimov, E. M. Oks, A. A. Zenin
Summary: The effect of longitudinal magnetic field on the emission characteristics of a forevacuum plasma electron source based on a discharge with a hollow cathode has been studied. It is found that the magnetic field decreases the plasma concentration on the axis of the cathode cavity, while increasing the diameter of the emission channel, leading to a significant increase in the emission current of electrons from the plasma.
PLASMA PHYSICS REPORTS
(2022)
Article
Physics, Fluids & Plasmas
Ilya Bakeev, Kirill Karpov, Aleksandr Klimov, Efim Oks, Aleksey Zenin
Summary: This paper investigates the features of focused electron beam transport in free space at elevated pressures. The effects of beam accelerating voltage, operating gas pressure, and magnetic focusing on beam trajectory are explored, particularly on beam convergence and divergence angles. The results show that the divergence angle increases with pressure, and for pressures greater than 5 Pa, the divergence angle is greater than the convergence angle. The findings are applied to electron beam transport experiments through a long narrow metal tube.
PLASMA SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Ceramics
A. S. Klimov, I. Yu Bakeev, E. M. Oks, A. A. Zenin
Summary: The results of pressureless electron beam sintering of Al2O3/Ti composite in the fore-vacuum range of pressure were investigated. A novel electron source was used to irradiate the surface of the compacted composite with a focused electron beam at a pressure of 30 Pa. The effects of different irradiation regimes and compact size on the properties of the sintered material were studied, including hardness, density, and porosity. The temperature variation across the sample thickness was also measured and calculated. It was found that the sintering process produced three regions with different porosity and hardness, with the middle region reaching a microhardness of 29 GPa. The formation of these regions was attributed to the low thermal conductivity of the alumina ceramic component of the composite. Sintering regimes that resulted in low porosity samples were identified.
CERAMICS INTERNATIONAL
(2023)
Article
Physics, Fluids & Plasmas
Ilya Yu. Bakeev, Aleksandr S. S. Klimov, Efim M. M. Oks, Aleksey A. A. Zenin
Summary: This study shows that the back-streaming ion flux of the high-voltage glow discharge facilitates the development of the hollow cathode effect. The effects of operating gas type and cathode hollow geometry on the initiating accelerating voltage have been studied, and it is proposed to use an auxiliary pulsed surface flashover discharge to trigger the hollow cathode discharge.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
A. A. Zenin, I. Yu Bakeev, A. S. Klimov, E. M. Oks, N. G. Rempe
Summary: We study the current flow in the circuit of a metal collector under electron beam irradiation at forevacuum pressures of 5-30 Pa. It is observed that when the collector surface is heated by the beam to a critical temperature, there is a sharp decrease in the measured current. This decrease is primarily attributed to thermionic emission from the collector surface, which can account for up to 50% or more of the electron beam current depending on the collector material.
Article
Materials Science, Multidisciplinary
I. Yu Bakeev, A. S. Klimov, E. M. Oks, A. A. Zenin
Summary: We investigated the transport of a focused electron beam through a long and narrow metal tube held at negative potential. The effect of electron beam parameters and tube potential on transport was explored. It was found that this effect is related to the initiation of a non-self-sustained glow discharge within the tube and the beam magnetic focusing parameters. Increasing the fraction of electrons transported through the tube promotes uniformity in the distributions of the non-self-sustained discharge current and discharge plasma density along the tube length.
Article
Physics, Fluids & Plasmas
Ilya Yu. Bakeev, Aleksandr S. Klimov, Efim M. Oks, Aleksey A. Zenin
Summary: We investigate the current distribution of a nonself-sustained glow discharge in a long, narrow metal tube when a focused electron beam generated by a forevacuum plasma-cathode gun is injected into the tube. The injection of accelerated electrons affects the distribution of current along the tube, with the minimum beam current needed for a uniform discharge decreasing as the tube diameter increases, the operating gas pressure increases, and the accelerating voltage decreases.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2023)
Article
Instruments & Instrumentation
A. S. Klimov, I. Yu. Bakeev, Yu. A. Burachevsky, J. E. Dagri, E. M. Oks, A. A. Zenin
Summary: We present the results of investigating a ribbon electron beam (10 x 220 mm(2)) generated by a two-stage discharge system using a hollow-cathode glow discharge plasma. The design of the source allows operation in the pressure range of 2 x 10(-2) to 10 Pa. Under a beam accelerating voltage of 8 kV, the beam current is 450 mA at a pressure of 2 x 10(-2) Pa and 150 mA at a pressure of 10 Pa. To achieve a uniform current density distribution, a specially designed emission electrode was used, reducing non-uniformities to 10%.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Materials Science, Multidisciplinary
Aleksandr S. Klimov, Ilya Yu. Bakeev, Anna V. Dolgova, Andrey V. Kazakov, Nikita S. Korablev, Aleksey A. Zenin
Summary: The results of electron beam processing on Mn-Zn ferrite samples show that continuous electron beam leads to surface structuring, changes in elemental composition, and modification of electrical properties. Millisecond pulse electron beam processing results in the formation of low zinc content melt islands while the remaining surface area remains largely unchanged. The thickness of the modified layer can be controlled by processing mode.
Article
Physics, Applied
A. S. Klimov, I. Yu Bakeev, A. A. Zenin, E. M. Oks, V. T. Tran
Summary: The size of the cathode gap plays a significant role in the initiation of the hollow-cathode effect, with a decrease in width leading to a disproportionate increase in threshold current and an increase in longitudinal size causing a sharp decrease in current.
TECHNICAL PHYSICS LETTERS
(2022)
