- Synthesis of Tungsten Heavy alloy Nanocomposite Powder by Ultrasonic-milling Process
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Seung-Chul Lee, Chang-Woo Lee, Sung-Soo Jung, Berm-Ha Cha, Jai-Sung Lee
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J Korean Powder Metall Inst. 2007;14(2):101-107.
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DOI: https://doi.org/10.4150/KPMI.2007.14.2.101
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- Ultrasonic-milling of metal oxide nanopowders for the preparation of tungsten heavy alloys was investigated. Milling time was selected as a major process variable. XRD results of metal oxide nanopowders ultrasonic-milled for 50 h and 100 h showed that agglomerate size reduced with increasing milling time and there was no evidence of contamination or change of composition by impurities. It was found that nanocomposite powders reduced at 800°C in a hydrogen atmosphere showed a chemical composition of 93.1W-4.9Ni-2.0Fe from EDS analysis. Hardness of sintered part using 50 h and 100 h powder samples was 399 Hv and 463 Hv, respectively, which is higher than the that of commercial products (330-340 Hv).
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Citations
Citations to this article as recorded by  - Grinding behavior of WO3, NiO, Fe2O3 by ultrasonic milling parameters control and preparation of nanocomposite powder
Keunhyuk Ryu, Kun-Jae Lee
Advanced Powder Technology.2020; 31(9): 3867. CrossRef - Investigation on Size Distribution of Tungsten-based Alloy Particles with Solvent Viscosity During Ultrasonic Ball Milling Process
KeunHyuk Ryu, HyeongSub So, JiSeok Yun, InHo Kim, Kun-Jae Lee
Journal of Korean Powder Metallurgy Institute.2019; 26(3): 201. CrossRef
- Synthesis of γ-Fe2O3 Nanoparticles by Low-pressure Ultrasonic Spraying
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Chang-Woo Lee, Soon-Gil Kim, Yong-Ho Choa, Jai-Sung Lee
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J Korean Powder Metall Inst. 2007;14(1):19-25.
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DOI: https://doi.org/10.4150/KPMI.2007.14.1.019
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Abstract
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- This study was focused on the optimization of low-pressure ultrasonic spraying process for synthesis of pure gamma-Fe_2O_3 nanoparticles. As process variables, pressure in the reactor, precursor concentration, and reaction temperature were changed in order to control the chemical and microstructural properties of iron oxide nanoparticles including crystal phase, mean particle size and particle size distribution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies revealed that pure gamma-Fe_2O_3 nanoparticles with narrow particle size distribution of 5-15 nm were successfully synthesized from iron pentacarbonyl (Fe(CO)_5) in hexane under 30 mbar with precursor concentrations of 0.1M and 0.2M, at temperatures over 800°C. Also magnetic properties, coercivity (H_c) and saturation magnetization (M_s) were reported in terms of the microstructure of particles based on the results from vibration sampling magnetometer (VSM).
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