Journal of Powder Materials

[Korean]
Synthesis of Hexagonal Boron Nitride Nanocrystals and Their Application to Thermally Conductive Composites: Jae-Yong Jung, Yang-Do Kim, Pyung-Woo Shin, Young-Kuk Kim; J Korean Powder Metall Inst. 2016;23(6):414-419. Published online December 1, 2016; DOI: https://doi.org/10.4150/KPMI.2016.23.6.414

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Abstract PDF: Much attention has been paid to thermally conductive materials for efficient heat dissipation of electronic devices to maintain their functionality and to support lifetime span. Hexagonal boron nitride (h-BN), which has a high thermal conductivity, is one of the most suitable materials for thermally conductive composites. In this study, we synthesize h-BN nanocrystals by pyrolysis of cost-effective precursors, boric acid, and melamine. Through pyrolysis at 900°C and subsequent annealing at 1500°C, h-BN nanoparticles with diameters of ~80 nm are synthesized. We demonstrate that the addition of small amounts of Eu-containing salts during the preparation of melamine borate precursors significantly enhanced the crystallinity of h-BN. In particular, addition of Eu assists the growth of h-BN nanoplatelets with diameters up to ~200 nm. Polymer composites containing both spherical Al₂O₃ (70 vol%) and Eu-doped h-BN nanoparticles (4 vol%) show an enhanced thermal conductivity (λ ~ 1.72W/mK), which is larger than the thermal conductivity of polymer composites containing spherical Al2O3 (70 vol%) as the sole fillers (λ ~ 1.48W/mK).

[Korean]
Improved Luminescent Characterization and Synthesis of InP/ZnS Quantum Dot with High-Stability Precursor: Eun-Jin Lee, Jong-Woo Moon, Yang-Do Kim, Pyung-Woo Shin, Young-Kuk Kim; J Korean Powder Metall Inst. 2015;22(6):385-390. Published online December 1, 2015; DOI: https://doi.org/10.4150/KPMI.2015.22.6.385

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We report a synthesis of non-toxic InP nanocrystals using non-pyrolytic precursors instead of pyrolytic and unstable tris(trimethylsilyl)phosphine, a popular precursor for synthesis of InP nanocrystals. In this study, InP nanocrystals are successfully synthesized using hexaethyl phosphorous triamide (HPT) and the synthesized InP nanocrystals showed a broad and weak photoluminescence (PL) spectrum. As synthesized InP nanocrystals are subjected to further surface modification process to enhance their stability and photoluminescence. Surface modification of InP nanocrystals is done at 230°C using 1-dodecanethiol, zinc acetate and fatty acid as sources of ZnS shell. After surface modification, the synthesized InP/ZnS nanocrystals show intense PL spectra centered at the emission wavelength 612 nm through 633 nm. The synthesized InP/ZnS core/shell structure is confirmed with X-ray diffraction (XRD) and Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES). After surface modification, InP/ZnS nanocrystals having narrow particle size distribution are observed by Field Emission Transmission Electron Microscope (FE-TEM). In contrast to uncapped InP nanocrystals, InP/ZnS nanocrystals treated with a newly developed surface modified procedure show highly enhanced PL spectra with quantum yield of 47%.

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Synthesis and luminescence characteristics of manganese-doped ZnSe quantum dots synthesized in aqueous solution through internal doping
Hyun Seon Hong, Yerin Kim, Jea Hyung Kim, Hyeon Seon Ryu, Dahye Song
Journal of the Korean Ceramic Society.2025;[Epub] CrossRef
Synthesis and Properties of InP/ZnS core/shell Nanoparticles with One-pot process
So Yeong Joo, Myung Hwan Hong, Leeseung Kang, Tae Hyung Kim, Chan Gi Lee
Journal of Korean Powder Metallurgy Institute.2017; 24(1): 11. CrossRef

[Korean]
Synthesis of Highly Dispersible Metal Nanoparticles in P3HT:PCBM Layers and Their Effects on the Performance of Polymer Solar Cells: Min-Ji Kim, Gyu-Chae Choi, Young-Kuk Kim, Yang-Do Kim, Youn-Kyoung Baek; J Korean Powder Metall Inst. 2014;21(3):179-184. Published online June 1, 2014; DOI: https://doi.org/10.4150/KPMI.2014.21.3.179

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Abstract PDF: In this study, we prepare polymer solar cells incorporating organic ligand-modified Ag nanoparticles (OAgNPs) highly dispersed in the P3HT:PCBM layer. Ag nanoparticles decorated with water-dispersible ligands (WAgNPs) were also utilized as a control sample. The existence of the ligands on the Ag surface was confirmed by FTIR spectra. Metal nanoparticles with different surface chemistries exhibited different dispersion tendencies. O-AgNPs were highly dispersed even at high concentrations, whereas W-AgNPs exhibited significant aggregation in the polymer layer. Both dispersion and blending concentration of the Ag nanoparticles in P3HT:PCBM matrix had critical effects on the device performance as well as light absorption. The significant changes in short-circuit current density (J_SC) of the solar cells seemed to be related to the change in the polymer morphology according to the concentration of AgNPs introduced. These findings suggested the importance of uniform dispersion of plasmonic metal nanoparticles and their blending concentration conditions in order to boost the solar cell performance.

[Korean]
The Effect of Binder Content for the Pore Properties of Fe Foam Fabricated by Slurry Coating Process: Jin Ho Choi, Sangsun Yang, Yang-Do Kim, Jung-Yeul Yun; J Korean Powder Metall Inst. 2013;20(6):439-444.; DOI: https://doi.org/10.4150/KPMI.2013.20.6.439

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6 Citations

Abstract PDF

Fe foam with above 90% porosity and 2 millimeter pore size was successfully fabricated by a slurry coating process. In this study, the binder contents were controlled to produce the Fe foam with different pore size, strut thickness and porosity. Firstly, the slurry was prepared by uniform mixing with Fe powders, distilled water and polyvinyl alcohol(PVA) as initial materials. After slurry coating on the polyurethane(PU) foam the sample was dried at 80°C. The PVA and PU foams were then removed by heating at 700°C for 3 hours. The debinded samples were subsequently sintered at 1250°C with holding time of 3 hours under hydrogen atmosphere. The three dimensional geometries of the obtained Fe foams with open cell structure were investigated using X-ray micro CT(computed tomography) as well as the pore morphology, size and phase.

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Interfacial Bonding and Abrasive Wear Behavior of Iron Matrix Composite Reinforced by Ceramic Particles
Yefei Li, Cong Li, Shuli Tang, Qiaoling Zheng, Juan Wang, Zhibo Zhang, Zhicheng Wang
Materials.2019; 12(22): 3646. CrossRef
A Fatigue Fracture Study on TDCB Aluminum Foam Specimen of Type Mode III Bonded with Adhesive
J.H. Lee, J.U. Cho
Archives of Metallurgy and Materials.2017; 62(2): 1359. CrossRef
Torsion Property of the Structure Bonded Aluminum Foam Due to Impact
G.W. Hwang, J.U. Cho
Archives of Metallurgy and Materials.2017; 62(2): 1353. CrossRef
Experimental Study On Fracture Property Of Double Cantilever Beam Specimen With Aluminum Foam
Y.C. Kim, H.K. Choi, J.U. Cho
Archives of Metallurgy and Materials.2015; 60(2): 1151. CrossRef
Experimental Study On Fracture Property Of Tapered Double Cantilever Beam Specimen With Aluminum Foam
Y.C. Kim, S.S. Kim, J.U. Cho
Archives of Metallurgy and Materials.2015; 60(2): 1459. CrossRef
The Effect of Fe and Fe2O3Powder Mixing Ratios on the Pore Properties of Fe Foam Fabricated by a Slurry Coating Process
Jin Ho Choi, Eun-Mi Jeong, Dahee Park, Sangsun Yang, Yoo-Dong Hahn, Jung-Yeul Yun
Journal of Korean Powder Metallurgy Institute.2014; 21(4): 266. CrossRef

[Korean]
Effect of Carboxylic Acid on Optical Properties of CuInS₂/ZnS Semiconductor Nanocrystals: Si-Hyun Ahn, Gyu-Che Choi, Yeun-Kyung Beak, Young-Kuk Kim, Yang-Do Kim; J Korean Powder Metall Inst. 2012;19(5):362-366.; DOI: https://doi.org/10.4150/KPMI.2012.19.5.362

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We report the effect of the chain length of carboxylic acid on the photoluminescence(PL) of CuInS_2/ZnS nanocrystals. CuInS_2/ZnS nanocrystals with emission wavelength ranging from 566 nm through 583 nm were synthesized with zinc acetate and carboxylic acids with various chain length. In this study, CuInS_2/ZnS nanocrystals prepared using long chain carboxylic acid showed more improved PL intensity. The origin of strong photoluminescence of the nanocrystals prepared with zinc acetate and long chain carboxylic acid was ascribed to improved size distribution due to strong reactivity between long chain carboxylic acid and zinc acetate.

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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
Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process
Aneeta Manjari Padhan, P. Ravikumar, P. Saravanan, Perumal Alagarsamy
Journal of Magnetism and Magnetic Materials.2016; 418: 253. CrossRef
Physical Properties Assessment of Soft Contact Lens with Halogen and Carboxylic Substituted Pyridine as Additive
Duck-Hyun Kim, A-Young Sung
Journal of Korean Ophthalmic Optics Society.2015; 20(4): 437. CrossRef
Improved Luminescent Characterization and Synthesis of InP/ZnS Quantum Dot with High-Stability Precursor
Eun-Jin Lee, Jong-Woo Moon, Yang-Do Kim, Pyung-Woo Shin, Young-Kuk Kim
Journal of Korean Powder Metallurgy Institute.2015; 22(6): 385. CrossRef

[Korean]
Effect of Pore Formers and Sintering Temperatures on Microstructure and Bending Strength of the Porous Zirconia Ceramics: Eun-Jung Lee, In-Hyuck Song, Jang-Hoon Ha, Yoo-Dong Hahn, Yang-Do Kim; J Korean Powder Metall Inst. 2011;18(6):502-509.; DOI: https://doi.org/10.4150/KPMI.2011.18.6.502

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Abstract PDF: In this study, a novel-processing route for fabricating microcellular zirconia ceramics has been developed. The proposed strategy for making the microcellula zirconia ceramics involved hollow microspheres as pore former. Compared to conventional dense microspheres pore former, well-defined pore structured zirconia ceramics were successfully fabricated. Effects of hollow microsphere content and sintering temperature on microstructure, porosity, pore distribution, and strength were investigated in the processing of microcellular zirconia ceramics.

[Korean]
A Study on the Applicability of Carbon Mold for Precision Casting of High Melting Point Metal: Chang-Wook Ji, Eun-Ju Yi, Yang-Do Kim, Young-Mok Rhyim; J Korean Powder Metall Inst. 2011;18(2):141-148.; DOI: https://doi.org/10.4150/KPMI.2011.18.2.141

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Carbon material shows relatively high strength at high temperature in vacuum atmosphere and can be easily removed as CO or CO_2 gas in oxidation atmosphere. Using these characteristics, we have investigated the applicability of carbon mold for precision casting of high melting point metal such as nickel. Disc shape carbon mold with cylindrical pores was prepared and Ni-base super alloy (CM247LC) was used as casting material. The effects of electroless Nickel plating on wettability and cast parameters such as temperature and pressure on castability were investigated. Furthermore, the proper condition for removal of carbon mold by evaporation in oxidation atmosphere was also examined. The SEM observation of the interface between carbon mold and casting materials (CM247LC), which was infiltrated at temperature up to 1600°C, revealed that there was no particular product at the interface. Carbon mold was effectively eliminated by exposure in oxygen rich atmosphere at 705°C for 3 hours and oxidation of casting materials was restrained during raising and lowering the temperature by using inert gas. It means that the carbon can be applicable to precision casting as mold material.

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Pore Structure and Characteristics of Hollow Spherical Carbon Foam According to Carbonization Temperature and Re-immersion Treatment
은주 이, 영목 임, 창우 이, 양도 김
Korean Journal of Materials Research.2013; 23(1): 24~30. CrossRef

[Korean]
A study on Magnetic Properties of BaFe₁₂O₁₉ Fabricated by Ultrasonic Spray-pyrolysis Process Using Self-Assembly Method: Moon-Hee Choi, Ji-Hun Yu, Dong-Hwan Kim, Kook-Chae Chung, Yang-Do Kim; J Korean Powder Metall Inst. 2010;17(4):263-269.; DOI: https://doi.org/10.4150/KPMI.2010.17.4.263

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Hexagonal barium ferrite (BaFe_12O_19) nano-particles have been successfully fabricated by spraypylorysis process. BaFe_12O_19 precursor solutions were synthesized by self-assembly method. Diethyleneamine (DEA) surfactant was used to fabricate the micelle structure of Ba-DEA complex under various DEA concentrations. BaFe_12O_19 powders were synthesized with addition of Fe ions to Ba-DEA complex and then fabricated BaFe_12O_19 powders by spray-pyrolysis process at the temperature range of 800sim1000°C. The molar ratio of Ba/DEA and heat-treatment temperatures significantly affected the magnetic properties and morphology of BaFe_12O_19 powders. BaFe_12O_19 powders synthesized with Ba/DEA molar ratio of 1 and heat-treated at 900°C showed the coercive forces (iHc) of 4.2 kOe with average crystal size of about 100 nm.

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Synthesize of Nd₂Fe₁₄B Powders from 1-D Nd₂Fe₁₄B Wires using Electrospinning Process
Nu Si A Eom, Su Noh, Muhammad Aneeq Haq, Bum Sung Kim
Journal of Korean Powder Metallurgy Institute.2019; 26(6): 477. CrossRef

[Korean]
A Study on Magnetic Properties of BaFe₁₂O_₁₉ Fabricated by Self-assembly Method: Moon-Hee Choi, Ji-Hun Yu, Dong-Hwan Kim, Hye-Mum Lee, Su-Min Kim, Yang-Do Kim; J Korean Powder Metall Inst. 2009;16(6):410-415.; DOI: https://doi.org/10.4150/KPMI.2009.16.6.410

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Hexagonal barium ferrite (BaFe_12O_19) nano-particles have been successfully synthesised using selfassembly method. Diethyleneamine (DEA) surfactant was used to fabricate the micelle structure of Ba-DEA complex under various DEA concentrations. BaFe_12O_19 powders were synthesized with addition Fe ions to Ba-DEA complex and then heat treated at temperature range of 800-1000°C. The molar ratio of Ba/DEA and heat-treatment temperature significantly affected the magnetic properties and morphology of BaFe_12O_19 powders. BaFe_12O_19 powders synthesized with Ba/DEA molar ratio of 1 and heat-treated at 1000°C for 1 hour showed the coercive forces (iHc) of 4.84 kOe with average crystal size of about 200 nm.

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A study on Magnetic Properties of BaFe12O19Fabricated by Ultrasonic Spray-pyrolysis Process Using Self-Assembly Method
Moon-Hee Choi, Ji-Hun Yu, Dong-Hwan Kim, Kook-Chae Chung, Yang-Do Kim
Journal of Korean Powder Metallurgy Institute.2010; 17(4): 263. CrossRef

[Korean]
Preparation and Characteristics of Elongated CdSe nanoparticles: Shin-Ho Kim, Myoung-Guk Park, Yang-Do Kim; J Korean Powder Metall Inst. 2008;15(3):210-213.; DOI: https://doi.org/10.4150/KPMI.2008.15.3.210

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Abstract PDF: Elongated CdSe nanoparticles with a diameter of 3-7nm have been successfully synthesized using two surfactants of trioctylphospine (TOP) and hexadecylamine (HDA) at 160°C. The formation of elongated CdSe nanoparticles is possibly due to the cooperative effects from both the different binding capability of two surfactants (TOP and HDA) and intrinsically anisotropic crystal structure of the CdSe. The electron diffraction pattern of CdSe nanoparticles revealed the formation of wurzite phase. The CdSe samples showed red-shifted wavelength from 560 to 580nm with increasing the refluxing time due to the gradual growth of CdSe nanoparticles. The relatively broad absorption band can be attributed to the surface state of CdSe nanoparticles. The possible formation mechanism of elongated CdSe nanoparticles was proposed and the characteristics of CdSe have been discussed as well.

[English]
Bi-materials of Al-Mg Alloy Reinforced with/without SiC and Al₂O₃ Particles; Processing and Mechanical Properties: Si-Young Chang, Han-Gyoung Cho, Yang-Do Kim; J Korean Powder Metall Inst. 2007;14(6):354-361.; DOI: https://doi.org/10.4150/KPMI.2007.14.6.354

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The bi-materials with Al-Mg alloy and its composites reinforced with SiC and Al_2O_3 particles were prepared by conventional powder metallurgy method. The A1-5 wt%Mg and composite mixtures were compacted under 150sim450;MPa, and then the mixtures compacted under 400 MPa were sintered at 773sim1173K for 5h. The obtained bi-materials with Al-Mg/SiCp composite showed the higher relative density than those with Al-Mg/Al_2O_3 composite after compaction and sintering. Based on the results, the bi-materials compacted under 400 MPa and sintered at 873K for 5h were used for mechanical tests. In the composite side of bi-materials, the SiC particles were densely distributed compared to the Al_2O_3 particles. The bi-materials with Al-Mg/SiC composite showed the higher micro-hardness than those with Al-Mg/Al_2O_3 composite. The mechanical properties were evaluated by the compressive test. The bi-materials revealed almost the same value of 0.2% proof stress with Al-Mg alloy. Their compressive strength was lower than that of Al-Mg alloy. Moreover, impact absorbed energy of bi-materials was smaller than that of composite. However, the bi-materials with Al-Mg/SiCp composite particularly showed almost similar impact absorbed energy to Al-Mg/Al_2O_3 composite. From the observation of microstructure, it was deduced that the bi-materials was preferentially fractured through micro-interface between matrix and composite in the vicinity of macro-interface.

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Effect of Heat Treatment on Microstructure and Mechanical Properties of Electromagnetic Duo-Cast Al Hybrid Material
Jun Young Suh, Sung Jin Park, Do-Kyun Kwon, Si Young Chang
Korean Journal of Materials Research.2018; 28(9): 499. CrossRef
Microstructure and Mechanical Behavior of Al-Mg-Si/Al Hybrid Alloy by Duo-casting
Ji-Min Han, Chong-Ho Kim, Jun-Pyo Park, Si Young Chang
Journal of the Korea Foundry Society.2012; 32(6): 269. CrossRef
Microstructure and Tensile Properties of Al-Mn/Al-Si Hybrid Aluminum Alloy Prepared by Electromagnetic Duo-Casting
Sung-Jin Park, Tingju Li, Chong-Ho Kim, Jun-Pyo Park, Si-Young Chang
Korean Journal of Materials Research.2012; 22(2): 97. CrossRef

[Korean]
Formation of CdSe Hollow Sphere by In-Situ-Template-Interface Reaction (ISTIR) Method: Moon-Hee Choi, Yoon-Bok Lee, Hyong-Kuk Kim, Young-Mok Rhyim, Jin-Chun Kim, Young-Seok Kim, Yang-Do Kim; J Korean Powder Metall Inst. 2005;12(4):291-295.; DOI: https://doi.org/10.4150/KPMI.2005.12.4.291

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Abstract PDF: CdSe hollow sphere with average size of about 30-50 nm was synthesized from the mixed solution of cadmium chloride (CdCl_2), sodium selenosulfate (Na_2SeSO_3) and ethylenediamine(EDA, H_2NCH_2CH_2NH_2) at room temperature. The molar ratio of EDA to Cd2+ showed the most significant effect on the morphology of CdSe hollow sphere. This paper will present and discuss the possible formation mechanism of CdSe hollow sphere based on the observation of morphological changes.

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