Journal of Powder Materials

Volume 12(3); June 2005

[English]
Installation for Preparing of Nanopowders by Target Evaporation with Pulsed Electron Beam: S. Sokovnin, Yu. Kotov, C. Rhee; J Korean Powder Metall Inst. 2005;12(3):167-173.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.167

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Production of weakly agglomerated nanopowders with the characteristic size of about 10 nm and a narrow particle size distribution is still a topical problem especially if the matter is an acceptable output (>50 g/hour), a high purity of the final product, and a low (energy consumption. The available experience and literature data show that the most promising approach to production of such powders is the evaporation-condensation method, which has a set of means for heating of the target. From this viewpoint the use of pulsed electron accelerators for production of nanopowders is preferable since they allow a relatively simple adjustment of the energy, the pulse length, and the pulse repetition rate. The use of a pulsed electron accelerator provides the following opportunities: a high-purity product; only the target and the working gas will interact and their purity can be controlled; evaporation products will be removed from the irradiation zone between pulses; as a result, the electron energy will be used more efficiently; adjustment of the particle size distribution and the characteristic size of particles by changing the pulse energy and the irradiated area. Considering the obtained results, we developed a design and made an installation for production of nanopowders, which is based on a hollow-cathode pulsed gas-filled diode. The use of a hollow-cathode gas-filled diode allows producing and utilizing an electron beam in a single chamber. The emission modulation in the hollow cathode will allow forming an electron beam 5 to 100 ms long. This will ensure an exact selection of the beam energy. By now we have completed the design work, manufactured units, equipped the installation, and began putting the installation into operation. A small amount of nanopowders has been produced.

Citations

Citations to this article as recorded by

Effect of the Enhanced Breakdown Strength in Plasma-Filled Optical System of Electron Beam Formation
V. I. Gushenets, A. S. Bugaev, E. M. Oks
Russian Physics Journal.2018; 60(9): 1515. CrossRef
Production of Nanopowders Using Pulsed Electron Beam
S. Yu. Sokovnin, V. G. Il'Ves
Ferroelectrics.2012; 436(1): 101. CrossRef

[Korean]
Characteristics of Titanium Carbide Fabricated by Fine Titanium Hydride Powder: Tek Sung, In-Shup Ahn, Sung-Yeal Bae, Woo Jeong, Dong-Kyu Park, Kwang Jung, You-Young Kim; J Korean Powder Metall Inst. 2005;12(3):174-178.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.174

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This paper deals with the fabrication of titanium carbide using fine titanium hydride. The ratio of TiH_2 and C (Activated carbon) was 1:1 (mol) and milled in a planetary ball mill at a ball-to-powder weight ratio of 20:1. Thereafter, TGA was performed at 1400°C to observe change of weight with milling time. Titanium carbide was obtained by using tempering the milled powders at 1100-1500°C. The microstructures of titanium carbide as well as the change of the lattice parameters and particle size have been studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Citations

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The Ni3Al–Al2O3/TiC cermet formation behavior with TiH2 base ball-milled powders with Ni, Al, and C during spark plasma sintering
Dong-Woong Kim, Sung-Hyun Choi, Kyoung-Rok Do, Su-Gun Lim, In-Shup Ahn
Research on Chemical Intermediates.2010; 36(6-7): 785. CrossRef

[English]
A study on the Active Material FeS₂ in Battery Fabricated by Mechanical Alloying: Woo-Hyun Jung, In-Shup Ahn, Hyo-Jun Ahn, Sung-Yeal Bae, Tek-Kyoung Sung, Tae-Bum Kim, You-Young Kim; J Korean Powder Metall Inst. 2005;12(3):179-185.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.179

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As the electrodes of secondary battery are made with sulfur compounds, excellent electrode system of environmental non-toxicity, high specific energy density and low material cost can be obtained. In this study, the FeS_2 fine compound powders for active material in the battery were synthesized by mechanical alloying. Fine Fe-53.5 wt.%S powders of 450 nm of mean size were fabricated by mechanical alloying for 60 hours at the horizontal attritor. As the mechanical alloying time increases, particle size of Fe-53.5 wt.%S was decreased and steady state of Fe-53.5 wt.%S compound powders was obtained at 30 hours. Fe-53.5 wt.%S cathode shows the excellent discharge capacity (1011 mAh/g).

Citations

Citations to this article as recorded by

Synthesis of Cathode Materials Fe-Doped NiS₂ by Mechanical Alloying for Li/NiS₂ Cells
Xiao Jing Liu, Dong Wook Park, Zhe Zhu Xu, Sang Dae Kang, In Shup Ahn, Hyo Jun Ahn
Advanced Materials Research.2011; 287-290: 1428. CrossRef
Synthesis of Nickel-Coated FeS₂ Particles as Active Material for Li/FeS₂ Cell by Mechanical Alloying
Xiao Jing Liu, Sang Dae Kang, Zhe Zhu Xu, In Shup Ahn
Materials Science Forum.2010; 658: 77. CrossRef
Electrochemical characteristics of Na/FeS2 battery by mechanical alloying
T.B. Kim, W.H. Jung, H.S. Ryu, K.W. Kim, J.H. Ahn, K.K. Cho, G.B. Cho, T.H. Nam, I.S. Ahn, H.J. Ahn
Journal of Alloys and Compounds.2008; 449(1-2): 304. CrossRef
Characteristics of (Fe, M)S₂ (M=Co, Ni, Mo) Composite Powders Fabricated by MCP
Woo Hyun Jung, Dong Kyu Park, Kwang Chul Jung, Se Hoon Suck, In Sup Ahn, Ki Won Kim
Materials Science Forum.2007; 534-536: 17. CrossRef

[Korean]
Formation of Aluminum Hydroxides by Hydrolysis of Nano and Micro Al Powders: Young Oh, Geunhee Lee, Joong Park, Chang Rhee, Whung Kim, Do Kim; J Korean Powder Metall Inst. 2005;12(3):186-191.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.186

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A formation of aluminum hydroxide by hydrolysis of nano and micro aluminum powder has been studied. The nano aluminum powder of 80 to 100 nm in diameter was fabricated by a pulsed wire evaporation (PWE) method. The micro powder was commercial product with more than 10;µm in diameter. The hydroxide type and morphology depending on size of the aluminum powder were examined by several analyses such as XRD, TEM, and BET. The hydrolysis procedure of micro aluminum powder was different from that of nano aluminum powder. The nano aluminum powder after immersing in the water was transformed rapidly to a nano fibrous boehmite, accompanying with a remarkable temperature increase, and then further transformed slowly to a stable bayerite. However, the micro powder was changed to the stable bayerite slowly and directly. The formation of fibrous aluminum hydroxide from nano aluminum powder might be due to the fine cracks which were formed by hydrogen gas pressure on the surface hydroxide layer during hydrolysis. The nano powder with large specific surface area and small size reacted more actively and faster than the micro powder, and transformed to meta-stable hydroxide in relatively short reaction time. Therefore, the formation of fibrous boehmite is special characteristic of hydrolysis of nano aluminum powder.

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Synthesis and Characterization of Glold Nanofluid Prepared by the Solution Plasma Processing
Yong-Kang Heo, Sang-Yul Lee
Journal of Korean Powder Metallurgy Institute.2010; 17(4): 342. CrossRef
A Study on Thermal Properties of Ethylene Glycol Containing Copper Oxide Nanoparticles
Chang-Kyu Kim, Gyoung-Ja Lee, Chang-Kyu Rhee
Journal of Korean Powder Metallurgy Institute.2010; 17(4): 276. CrossRef

[Korean]
Synthesis of Fine Copper Powders from CuO-H₂O Slurry by Wet-reduction Method: Jong-Gwan Ahn, Dong-Jin Kim, Ik-Kyu Lee, Jaeryeung Lee, Liang Huanzhen; J Korean Powder Metall Inst. 2005;12(3):192-200.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.192

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Abstract PDF: Ultrafine copper powder was prepared from CuO-H_2O slurry with hydrazine, a reductant, under 70°C. The influence of various reaction parameters such as temperature, reaction time, molar ratio of N_2H_4, PvP and NaOH to Cu in aqueous solution had been studied on the morphology and powder phase of Cu powders obtained. The production ratio of Cu from CuO was increased with the ratio of N_2H_4/Cu and the temperature. When the ratio of N_2H_4/Cu was higher than 2.5 and the temperature was higher than 60°C, CuO was completely reduced into Cu within 40 min. The crystalline size of Cu obtained became fine as the temperature increase, whereas the aggregation degree of particles was increased with the reaction time. The morphology of Cu powder depended on that of the precursor of CuO and processing conditions. The average particle size was about 0.5µm.

[Korean]
Size Control of Nickel Powders from Nickel Chloride Solution Containing Ammonia in DEA Solutions: Eun Choi, Yoon Lee, Suk Yoon, Kwang Kim, Jin Kim, Young Rhyim, Hyong Kim, Yang Kim; J Korean Powder Metall Inst. 2005;12(3):201-207.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.201

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Abstract PDF: Nickel powders were synthesized by the hydrazine reduction of nickel chloride solution containing ammonia in DEA solutions. The size distribution of nickel powders were investigated as a function of ammonia concentration, hydrazine concentration and the mixed composition ratio of diethanolammine (DEA) and triethanolammine (TEA). Nickel powders with the size in submicron range were obtained at 185°C for 45 minutes by hydrazine reduction of nickel chloride solution in DEA solutions. The hydrazine concentrations showed significant effects on the particle size and shape distribution of nickel powders under NH_3/Ni2+ molar ratio of 2.0 condition. As the mixed volume ratio of TEA and DEA increased, nickel powders with relatively larger particle size and low agglomeration were obtained. Nickel powders with particle size in the ranged from 0.4 to 0.9;µm were obtained at the 50 vol.% of TEA.

[Korean]
Fabrication of Quasi-crystal Strengthened Aluminum Composites by Mechanical Milling Process: Woo Jang, Kwang Shin; J Korean Powder Metall Inst. 2005;12(3):208-213.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.208

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Aluminum matrix composites strengthened by the quasi-crystalline (QC) phase were developed in the present study. The icosahedral Al_65Cu_20Fe_15 phase was produced by gravity casting and subsequent heat treatment. The mechanical milling process was utilized in order to produce the Al/QC composite powders. The microstructures of the composite powders were examined by optical microscopy (OM) and scanning electron microscopy (SEM). The composite powders were subsequently canned, degassed and extruded in order to produce the bulk composite extrusions with various volume fractions of QC. The microstructure and mechanical properties of the extrusions were examined by OM, SEM, Vickers hardness tests and compression tests. It was found that the microstructures of the Al/QC composites were uniform and the mechanical properties could be significantly improved by the addition of the QC phase.

Citations

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Grinding Behaviour of Aluminum Powder for Al/CNTs Nano Composites Fabrication by Dry Grinding Process Using a High Speed Planetary Ball Mill
Heekyu Choi, Jehyun Lee, Seongsoo Kim, Gyungpil Choi, Daehyung Bae, Sungbak Lee, Woong Lee
Korean Journal of Materials Research.2013; 23(2): 89. CrossRef
Fabrication of Aluminum/Aluminum Nitride Composites by Reactive Mechanical Alloying
Seung Hoon Yu, Kwang Seon Shin
Materials Science Forum.2007; 534-536: 181. CrossRef

[Korean]
Effect of Mechanical Alloying Atmosphere on Formation of AlN: Seung-Hoon Yu, Young Lee, Kwang-Seon Shin; J Korean Powder Metall Inst. 2005;12(3):214-219.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.214

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In order to investigate the formation of AlN, mechanical alloying was carried out in N_2 and NH_3 atmosphere. Differential thermal analysis (DTA), x-ray diffraction (XRD) and chemical analysis were carried out to examine the formation behavior of aluminum nitrides. No diffraction pattern of AlN was observed in XRD analysis of the as-milled powders in NH_3;or;N_2 atmosphere. However, DTA and chemical analysis indicated that the precursors for AlN were formed in the Al powders milled in NH_3 atmosphere. The AlN precursors transformed to AlN after heat treatment at and above 600°C. It was considered that the reaction between Al and NH_3 was possible by the formation of fresh Al surface during mechanical alloying of Al powders.

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Synthesis of Al/AlN Composites by Mechanical Alloying and the Effect of PCA on Their Properties
Seok-Hyeoun Kim, Yong-Jin Kim, Jung-Ho Ahn
Journal of Korean Powder Metallurgy Institute.2011; 18(3): 238. CrossRef

[Korean]
Synthesis and Characterization of Nanoporous Boehmite: Ho-Kun Kim, Tae-Young Kim; J Korean Powder Metall Inst. 2005;12(3):220-224.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.220

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Abstract PDF: Boehmite (AlOOH) powder with uniform pore size and high specific surface area were synthesized via sol-gel method using metal salts, Al_2(SO_4)_3 and NaAlO_2. During these synthetic process, the effects of the aging time were investigated to determine the optimal synthetic conditions of boehmite. X-ray diffraction, BET, Raman/IR, and scanning electron microscopy techniques were used for the characterization of the powder. Boehmite gel synthesized at the first stage of the experimental procedure transformed to crystalline boehmite phase after aging for 6 hours. The specific surface area of the crystalline boehmite showed a maximum value, 350m2/g, at aging time of 72 hours. The pore size of the boehmite increased with increasing aging time and the boehmite with average pore diameter of 3.6 nm was obtained at aging time of 96 hours.

[Korean]
A Study on Oxidation-Resistance of Iron Nanoparticles Synthesized by Chemical Vapor Condensation Process: Dong-Won Lee, Ji-Hun Yu, Jeoung-Hyun Bae, Tae-Suk Jang, Byoung-Kee Kim; J Korean Powder Metall Inst. 2005;12(3):225-230.; DOI: https://doi.org/10.4150/KPMI.2005.12.3.225

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Abstract PDF: In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below 130°C in air was 10~40 times higher than that of the air- passivated particles.

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