Journal of Powder Materials

Shape Control of Platinum Nanoparticles Using a Metal Salt: Seoung Yeul Kwak, Jin Ho Lee, Jin Woo Kim, Taek Kyun Jung, Young Do Kim; J Korean Powder Metall Inst. 2012;19(6):393-397.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.393

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Abstract PDF: AgNO_3 has the characteristic is controlling the inhibition or promotion of particle growth by adsorbing onto specific facets of platinum nanoparticles. Therefore, in this study, AgNO_3 was added to control the shape of platinum nanoparticles during the liquid phase reduction process. Consequently, platinum cubes were synthesized when AgNO_3 of 1.1 mol% (with respect to the Pt concentration) was added into the solution. Platinum octahedrons were synthesized when 32 mol% (with respect to the Pt concentration) was added into the solution. These results demonstrate that the metal salt AgNO_3, effectively controlled the relative growth rates of each facet of Pt nano particles.

Characteristics of the Ammonium Diuranate Powders Prepared with Different Experimental Apparatus in Sol-gel Process: Yeon-Ku Kim, Kyung-Chai Jeong, Sung-Ho Ueom, Moon Sung Cho; J Korean Powder Metall Inst. 2012;19(6):398-404.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.398

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Abstract PDF: This paper describes the spherical ammonium diuranate gel particles which are the intermediated material of the UO_2 microsphere for an VHTR(very high temperature reactor) nuclear fuel. The characteristics of the intermediate-ADU gel particles prepared by AWD(ageing, washing, and drying) and FB(fluidized-bed) apparatus were examined and compared in a sol-gel fabrication process. The electrical conductivity of washing filtrate from the FB treating and the surface area of dried-ADU gel particles were higher than those of AWD treating. Also, an internal pore volume in dried-ADU gel particles showed a more decrease in AWD treatment than FB treatment because of decomposition of PVA affected by the washing time. However, the internal microstructures of ADU gel particles were similar regardless of the process variation.

Recovery of Copper Powder form MoO₃ Leaching Solution Using Cementation Reaction System: Geon-Hong Kim, Hyun-Seon Hong, Hang-Chul Jung; J Korean Powder Metall Inst. 2012;19(6):405-411.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.405

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Recovery of copper powder from copper chloride solution used in MoO_3 leaching process was carried out using a cementation method. Cementation is a simple and economical process, necessitating less energy compared with other recovery methods. Cementation utilizes significant difference in standard reduction potential between copper and iron under standard condition. In the present research, Cementation process variables of temperature, time, and added amount of iron scraps were optimized by using design of experiment method and individual effects on yield and efficiency of copper powder recovery were investigated using bench-scale cementation reaction system. Copper powders thus obtained from cementation process were further characterized using various analytical tools such as XRF, SEM-EDS and laser diffraction and scattering methods. Cementation process necessitated further purification of recovered copper powders and centrifugal separation method was employed, which successfully yielded copper powders of more than 99.65% purity and average 1µm in size.

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Recovery of Tin as Tin oxide nanoparticles from waste printed circuit boards for photocatalytic dye degradation
Dina Magdy Abdo, Sabah Mohamed Abdelbasir, Shakinaz Taha El-Sheltawy, Ibrahim Ahmed Ibrahim
Korean Journal of Chemical Engineering.2021; 38(9): 1934. CrossRef
Development of Pre-treatment for Tin Recovery from Waste Resources
Y.H. Jin, D.H. Jang, H.C. Jung, K.W. Lee
Journal of Korean Powder Metallurgy Institute.2014; 21(2): 142. CrossRef

The Effect of Calcination Temperature on the Synthesis of Quartz glass by Fumed Silica Sintering: J.H. Maeng, K.H. Yoon, D.W. Shin, S.C. Choi, T.Y. Lim, H.J. Kim; J Korean Powder Metall Inst. 2012;19(6):412-415.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.412

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The quartz glasses were prepared by sintering of fumed silica powders and the effect of OH concentration on their surface on sintering was studied. Through the firing process, the fumed silica was crystallized from 1180 to 1260°C region. The amount of hydroxyl group decreased with increase in calcination temperature and consequently the crystallization was prevented. A transparent quartz glass was obtained from fumed silica, previously calcined at 1000°C, by the sintering at 1250°C for 1 h.

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Fabrication of transparent amorphous silica by controlling forming and sintering processes with spherical nano-silica powder
Yoo Kyoung Ahn, Dong Hwi Kim, Hyung Sup Lim, Sang Jin Lee
Journal of the Korean Ceramic Society.2022; 59(6): 787. CrossRef
The Effect of Sintering Temperature on the Synthesis of Quartz glass by Fumed Silica Sintering
J.H. Maeng, K.H. Yoon, S.C. Choi, H.J. Kim
Journal of Korean Powder Metallurgy Institute.2013; 20(2): 134. CrossRef

A Study of Mechanical Properties and Microstructure of ZrO₂-Ag Depending on the Composite Route: In-Chul Yeo, Jae-Kil Han, In-Cheol Kang; J Korean Powder Metall Inst. 2012;19(6):416-423.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.416

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Abstract PDF: This paper introduces an effect of a preparing ZrO_2-Ag composite on its mechanical properties and microstructure. In present study, ZrO_2-Ag was prepared by reduction-deposition route and wetting dispersive milling method, respectively. Two type of Ag powders (nano Ag and micron Ag size, respectively) were dispersed into ZrO_2 powder during wetting dispersive milling in D.I. water. Each sample was sintered at 1450°C for 2hr in atmosphere, and then several mechanical tests and analysis of microstructure were carried out by bending test, hardness, fracture toughness and fracture surface microstructure. As for microstructure, the Ag coated ZrO_2 showed homogeneously dispersed Ag in ZrO_2 in where pore defect did not appear. However, ZrO_2-nano Ag and ZrO_2-micro Ag composite appeared Ag aggregation and its pore defect, which carried out low mechanical property and wide error function value.

Microstructure and Synthesis of Nano Palladium Spot Coated Activated Carbon Powders by Hydrothermal Attachment Method: Hyeong Chul Kim, Jae Kil Han; J Korean Powder Metall Inst. 2012;19(6):424-428.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.424

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Abstract PDF: Nano Pd spot-coated active carbon powders were synthesized by a hydrothermal-attachment method (HAA) using PVP capped Pd colloid in a high pressure bomb at 250°C, 450 psi, respectively. The PVP capped Pd colloid was synthesized by the precipitation-redispersion method. PVP capped Pd nano particles showed the narrow size distribution and their particle sizes were less than 8nm in diameter. In the case of nano Pd-spot coated active carbon powders, nano-sized Pd particles were adhered in the active carbon powder surface by HAA method. The component of Pd was homogeneously distributed on the active carbon surface.

Phase Evolution and Thermal Conductivities of (La_1-xGd_x)₂Zr₂O₇ Oxides for Thermal Barrier Coatings: Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seong Won Kim; J Korean Powder Metall Inst. 2012;19(6):429-434.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.429

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With increase in operating temperature of gas turbine for higher efficiency, it is necessary to find new materials of TBC for replacement of YSZ. Among candidate materials for future TBCs, zirconate-based oxides with pyrochlore and fluorite are prevailing ones. In this study, phase structure and thermal conductivities of (La_1-xGd_x)_2Zr_2O_7 oxide system are investigated. (La_1-xGd_x)_2Zr_2O_7 system are comprised by selecting La3+/Gd3+ as A-site ions and Zr4+ as B-site ion in A_2B_2O_7 pyrochlore structures. With powder mixture from each oxide, (La_1-xGd_x)_2Zr_2O_7 oxides are fabricated via solid-state reaction at 1600°C. Either pyrochlore or fluorite or mixture of both appears after heat treatment. For the developed phases along (La_1-xGd_x)_2Zr_2O_7 compositions, thermal conductivities are examined, with which the potential of (La_1-xGd_x)_2Zr_2O_7 compositions for TBC application is also discussed.

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Fabrication and Characterization of Ceramics and Thermal Barrier Coatings of Lanthanum Zirconate with Reduced Rare-earth Contents in the La2O3-ZrO2 System
Chang-Sup Kwon, Sujin Lee, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seongwon Kim
Journal of Korean Powder Metallurgy Institute.2015; 22(6): 413. CrossRef
Preparation of Suspension in La2O3-Gd2O3-ZrO2System via Planetary Mill and Characteristics of (La1-xGdx)2Zr2O7Coatings Fabricated via Suspension Plasma Spray
Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seongwon Kim
Journal of Korean Powder Metallurgy Institute.2013; 20(6): 453. CrossRef
Fabrication and Characteristics of Yttria-stabilized Zirconia (7.5 wt% Y2O3-ZrO2) Coating Deposited via Suspension Plasma Spray
Won-Jun Lee, Chang-Sup Kwon, Seongwon Kim, Yoon-Suk Oh, Hyung-Tae Kim, Dae-Soon Lim
Journal of Korean Powder Metallurgy Institute.2013; 20(6): 445. CrossRef

Effect of Sintering Temperature on the High Temperature Oxidation of Fe-Cr-Al Powder Porous Metal Manufactured by Electrospray Process: Jae-Sung Oh, Young-Min Kong, Byoung-Kee Kim, Kee-Ahn Lee; J Korean Powder Metall Inst. 2012;19(6):435-441.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.435

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A new manufacturing process of Fe-Cr-Al powder porous metal was attempted. First, ultra-fine fecralloy powders were produced by using the submerged electric wire explosion process. Evenly distributed colloid (0.05~0.5% powders) was dispersed on PU (Polyurethane) foam through the electrospray process. And then degreasing and sintering processes were conduced. In order to examine the effect of sintering temperature in process, pre-samples were sintered for two hours at temperatures of 1350°C, 1400°C, 1450°C, and 1500°C, respectively, in H_2 atmospheres. A 24-hour TGA (thermo gravimetric analysis) test was conducted at 1000°C in a 79% N_2+21% O_2 to investigate the high temperature oxidation behavior of powder porous metal. The results of the high temperature oxidation tests showed that oxidation resistance increased with increasing sintering temperature (2.57% oxidation weight gain at 1500°C sintered specimen). The high temperature oxidation mechanism of newly manufactured Fe-Cr-Al powder porous metal was also discussed.

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Effect of Cell Size on the High Temperature Oxidation Properties of Fe-Cr-Al Powder Porous Metal Manufactured by Electro-spray Process
Jae-Sung Oh, Young-Min Kong, Byoung-Kee Kim, Kee-Ahn Lee
Journal of Korean Powder Metallurgy Institute.2014; 21(1): 55. CrossRef

Luminescent Characteristics of CdSe Quantum Dot Phosphor Depending on Se Precursor Ratio: Nu Si A Eom, Taek-Soo Kim, Yong-Ho Choa, Bum Sung Kim; J Korean Powder Metall Inst. 2012;19(6):442-445.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.442

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The quantum dots (QD) have unique electrical and optical properties due to quantum dot confinement effect. The optical properties of QDs are decided by various synthesis conditions. In a prior QDs study, a study on the QDs size with synthesis condition such as synthesis time and temperature is being extensively researched. However, the research on QDs size with composition ratio has hitherto received scant attention. In order to evaluate the ratio dependence of CdSe crystal, synthesis ratio of Se precursor is changed from 16.7 mol%Se to 44 mol%Se. As the increasing Se ratio, the band gap was increased. This is caused by red shift of emission. We confirmed optical property of CdSe QDs with composition ratio.

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Synthesis and analysis CdSe/ZnS quantum dot with a Core/shell Continuous Synthesis System Using a Microfluidic Reactor
Myung Hwan Hong, So Young Joo, Lee-Seung Kang, Chan Gi Lee
Journal of Korean Powder Metallurgy Institute.2018; 25(2): 132. CrossRef
Multimodal luminescence properties of surface-treated ZnSe quantum dots by Eu
Ji Young Park, Da-Woon Jeong, Kyoung-Mook Lim, Yong-Ho Choa, Woo-Byoung Kim, Bum Sung Kim
Applied Surface Science.2017; 415: 8. CrossRef
Optical Characteristics of CdSe/ZnS Quantum Dot with Precursor Flow Rate Synthesized by using Microreactor
Ji Young Park, Da-Woon Jeong, Won Ju, Han Wook Seo, Yong-Ho Choa, Bum Sung Kim
journal of Korean Powder Metallurgy Institute.2016; 23(2): 91. CrossRef

Fabrication of Porous Mo by Freeze-Drying and Hydrogen Reduction of MoO₃/Camphene Slurry: Wonsuk Lee, Sung-Tag Oh; J Korean Powder Metall Inst. 2012;19(6):446-450.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.446

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In order to fabricate the porous Mo with controlled pore characteristics, unique processing by using MoO_3 powder as the source and camphene as the sublimable material is introduced. Camphene-based 15 vol% MoO_3 slurries, prepared by milling at 50°C with a small amount of dispersant, were frozen at -25°C. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was hydrogen-reduced at 750°C, and sintered at 1000-1100°C for 1 h. After heat treatment in hydrogen atmosphere, MoO_3 powders were completely converted to metallic W without any reaction phases. The sintered samples showed large pores with the size of about 150µm which were aligned parallel to the camphene growth direction. Also, the internal wall of large pores and near bottom part of specimen had relatively small pores due to the difference in the camphene growth rate during freezing process. The size of small pores was decreased with increase in sintering temperature, while that of large pores was unchanged. The results are strongly suggested that the porous metal with required pore characteristics can be successfully fabricated by freeze-drying process using metal oxide powders.

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Effect of Heat Treatment Atmosphere on the Microstructure of TiH2-MoO3 Powder Mixtures
Ki Cheol Jeon, Sung Hyun Park, Na-Yeon Kwon, Sung-Tag Oh
Journal of Korean Powder Metallurgy Institute.2016; 23(4): 303. CrossRef
Fabrication of Porous Cu by Freeze-drying Process of Camphene Slurry with CuO-coated Cu Powders
Su-Ryong Bang, Sung-Tag Oh
Journal of Korean Powder Metallurgy Institute.2014; 21(3): 191. CrossRef
Synthesis and Antifungal Property of Porous Al2O3with Dispersions of Cu Nanoparticles
Ho-Suk Yoo, Min-Sung Kim, Sung-Tag Oh, Chang-Yong Hyun
Journal of Korean Powder Metallurgy Institute.2014; 21(1): 16. CrossRef
Fabrication of Porous Cu-Ni by Freeze Drying and Hydrogen Reduction of CuO-NiO Powder Mixture
Han Gil Seo, Sung-Tag Oh
Journal of Korean Powder Metallurgy Institute.2014; 21(1): 34. CrossRef
Freeze Drying for Porous Mo with Sublimable Vehicles of Eutectic System
Gyu-Tae Lee, Han Gil Seo, Myung-Jin Suk, Sung-Tag Oh
Journal of Korean Powder Metallurgy Institute.2013; 20(4): 253. CrossRef

Present Status and Future Prospect of Quantum Dot Technology: H.S. Hong, K.S. Park, C.G. Lee, B.S. Kim, L.S. Kang, Y.H. Jin; J Korean Powder Metall Inst. 2012;19(6):451-457.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.451

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Nowadays, research and development on quantum dot have been intensively and comprehensively pursued worldwide in proportion to concurrent breakthrough in the field of nanotechnology. At present, quantum dot technology forms the main interdisciplinary basis of energy, biological and photoelectric devices. More specifically, quantum dot semiconductor is quite noteworthy for its sub-micro size and possibility of photonic frequency modulation capability by controlling its size, which has not been possible with conventionally fabricated bulk or thin film devices. This could lead to realization of novel high performance devices. To further understand related background knowledge of semiconductor quantum dot at somewhat extensive level, a review paper is presently drafted to introduce basics of (semiconductor) quantum dot, its properties, applications, and present and future market trend and prospect.

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Charge carrier analysis via impedance spectroscopy and the achievement of high performance in CdSe/ZnS:di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane hybrid quantum dot light-emitting diodes
Dongjin Kim, Ohun Kwon, Mijin Kim, Honyeon Lee
Organic Electronics.2022; 108: 106593. CrossRef
Facile synthesis and characterization of zinc selenide nanoparticles in aqueous solution at room temperature
Hyun Seon Hong, Mi-So Kim, Eun Kyung Byun, You Lim Lee
Journal of Crystal Growth.2020; 535: 125523. CrossRef
Study on UV Opto-Electric Properties of ZnS:Mn/ZnS Core-Shell QD
Yun-Ji Lee, Ji-Min Cha, Chang-Bun Yoon, Seong-Eui Lee
Journal of the Korean Ceramic Society.2018; 55(1): 55. CrossRef
Surface Treatment Method for Long-term Stability of CdSe/ZnS Quantum Dots
Hyun-Su Park, Da-Woon Jeong, Bum-Sung Kim, So-Yeong Joo, Chan-Gi Lee, Woo-Byoung Kim
Journal of Korean Powder Metallurgy Institute.2017; 24(1): 1. CrossRef
Growth mechanism of InP and InP/ZnS synthesis using colloidal synthesis
Han wook Seo, Da-woon Jeong, Bin Lee, Seoung kyun Hyun, Bum Sung Kim
Journal of Korean Powder Metallurgy Institute.2017; 24(1): 6. CrossRef
Exact piezoelectric solution for misfitted inclusion in finite spherical matrix: Applications to quantum dot core/shell crystals
S.Y. Seo, S.S. Yoo, D. Mishra, S.-H. Park, Y.E. Pak
International Journal of Solids and Structures.2016; 94-95: 158. CrossRef
The Status of Research of Quantum dot Using 4P Analysis -Focusing on the application and convergence field of quantum technology
Na-Young Heo, Young-Joo Ko
Journal of the Korea Convergence Society.2015; 6(2): 49. CrossRef

Trend in Development of Metal Fiber Fabrication Process: Man Ho Park, Jung Yeul Yun, Yoo Dong Hahn, Yo Seung Song; J Korean Powder Metall Inst. 2012;19(6):458-465.; DOI: https://doi.org/10.4150/KPMI.2012.19.6.458

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Filtration efficiency of woven metal fiber filter for aerosol generated by plasma torch metal cutting
Min-Ho Lee, Hee Kwon Ku, Hyunjin Boo, Jonghyeon Kim, Geundong Song, Deokhee Lee, Kaphyun Yoo, Byung Gi Park
Aerosol Science and Technology.2023; 57(10): 949. CrossRef

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