Journal of Powder Materials

Hyung-Tae Kim

16 Articles

Preparation of Suspension in La₂O₃-Gd₂O₃-ZrO₂ System via Planetary Mill and Characteristics of (La_1-xGd_x)₂Zr₂O₇ Coatings Fabricated via Suspension Plasma Spray: Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seongwon Kim; J Korean Powder Metall Inst. 2013;20(6):453-459.; DOI: https://doi.org/10.4150/KPMI.2013.20.6.453

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Lanthanum/gadolinium zirconate coatings are deposited via suspension plasma spray with suspensions fabricated by a planetary mill and compared with hot-pressed samples via solid-state reaction. With increase in processing time of the planetary mill, the mean size and BET surface area change rapidly in the case of lanthanum oxide powder. By using suspensions of planetary-milled mixture between lanthanum or gadolinium oxide and nano zirconia, dense thick coatings with fully-developed pyrochlore phases are obtained. The possibilities of these SPS-prepared coatings for TBC application are also discussed.

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Phase Equilibria in the ZrO2–La2O3–Gd2O3 System at 1600°C
E.R. Andrievskaya, O.A. Kornienko, A.I. Bykov, A.V. Sameliuk
Powder Metallurgy and Metal Ceramics.2020; 58(11-12): 714. CrossRef
Characteristics of Bulk and Coating in Gd2−xZr2+xO7+0.5x(x = 0.0, 0.5, 1.0) System for Thermal Barrier Coatings
Sun-Joo Kim, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seongwon Kim
Journal of the Korean Ceramic Society.2016; 53(6): 652. CrossRef
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
Structure and Thermal Conductivity of Thermal Barrier Coatings in Lanthanum/Gadolinium Zirconate System Fabricated via Suspension Plasma Spray
Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seongwon Kim
Journal of the Korean institute of surface engineering.2014; 47(6): 316. 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; J Korean Powder Metall Inst. 2013;20(6):445-452.; DOI: https://doi.org/10.4150/KPMI.2013.20.6.445

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Yttria-stabilized zirconia (YSZ) coatings are fabricated via suspension plasma spray (SPS) for thermal barrier applications. Three different suspension sets are prepared by using a planetary mill as well as ball mill in order to examine the effect of starting suspension on the phase evolution and the microstructure of SPS prepared coatings. In the case of planetary-milled commercial YSZ powder, a deposited thick coating turns out to have a dense, vertically-cracked microstructure. In addition, a dense YSZ coating with fully developed phase can be obtained via suspension plasma spray with suspension from planetary-milled mixture of Y_2O_3 and ZrO_2.

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Fabrication and Characterization of 7.5 wt% Y2O3-ZrO2Thermal Barrier Coatings Deposited by Suspension Plasma Spray
Won-Jun Lee, Yoon-Suk Oh, Sung-Min Lee, Hyung-Tae Kim, Dae-Soon Lim, Seongwon Kim
Journal of the Korean Ceramic Society.2014; 51(6): 598. CrossRef
Structure and Thermal Conductivity of Thermal Barrier Coatings in Lanthanum/Gadolinium Zirconate System Fabricated via Suspension Plasma Spray
Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seongwon Kim
Journal of the Korean institute of surface engineering.2014; 47(6): 316. CrossRef

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 the Size and Amount of SiC on the Microstructures and Thermal Conductivities of ZrB₂-SiC Composite Ceramics: Seong-Won Kim, Chang-Sup Kwon, Yoon-Suk Oh, Sung-Min Lee, Hyung-Tae Kim; J Korean Powder Metall Inst. 2012;19(5):379-384.; DOI: https://doi.org/10.4150/KPMI.2012.19.5.379

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This paper reports the microstructures and thermal conductivities of ZrB_2-SiC composite ceramics with size and amount of SiC. We fabricated sintered bodies of ZrB_2-x vol.% SiC (x=10, 20, 30) with submicron and nanosized SiC densified by spark plasma sintering. Microstructure retained the initial powder size of especially SiC, except the agglomeration of nanosized SiC. For sintered bodies, thermal conductivities were examined. The observed thermal conductivity values are 40~60 W/mK, which is slightly lower than the reported values. The relation between microstructural parameter and thermal conductivity was also discussed.

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Analysis of Polymer Hybrid-coated Anodic Aluminum Oxide
Mira Kim, Yeongwoo Kim, Hakyoung Lee, Chan-Young Park, Won-Ki Lee, Taeho Kang, Kwon Taek Lim
Molecular Crystals and Liquid Crystals.2015; 622(1): 120. CrossRef
Thermal Properties of Diamond Aligned Electroless Ni Plating Layer/Oxygen Free Cu Substrates
Da-Woon Jeong, Song-Yi Kim, Kyoung-Tae Park, Seok-Jun Seo, Taek Soo Kim, Bum Sung Kim
Journal of Korean Powder Metallurgy Institute.2015; 22(2): 134. CrossRef
Effect of the SiC Size on the Thermal and Mechanical Properties of Reaction-bonded Silicon Carbide Ceramics
Chang-Sup Kwon, Yoon-Suk Oh, Sung-Min Lee, Yoonsoo Han, Hyun-Ick Shin, Youngseok Kim, Seongwon Kim
Journal of Korean Powder Metallurgy Institute.2014; 21(6): 467. CrossRef

Thermo-Mechanical Properties of Al₂TiO₅ Ceramics Stabilized with MgO and ZrO₂ Additives: Da-Mi Kim, Hyung-Tae Kim, Hyeong-Jun Kim, Ik-Jin Kim, Seong-Cheol Choi, Yong-Chan Kim, Jung NamKung, Sung-Soo Ryu; J Korean Powder Metall Inst. 2012;19(4):253-258.; DOI: https://doi.org/10.4150/KPMI.2012.19.4.253

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The characteristics of Al_2TiO_5 ceramics were influenced by the additives and the heat treatment that controls the microcrack behavior at grain boundaries. The effect of additives on Al_2TiO_5 ceramics were investigated in terms of mechanical properties and thermal expansion at high temperature. The Al_2TiO_5 were synthesized at 1500°C, 1550°C and 1600°C for 2h by reaction sintering. The formation of Al_2TiO_5 phase was increased by additives that enhanced the volume of the microcrack that can lead to low thermal expansion. The mechanical properties of the stabilized Al_2TiO_5 ceramics were increased remarkably at 1100°C, 1200°C and 1300°C due to the oneset of mechanical healing of grain-bondary microcracks at a high temperature. The amount of microcrack was decreased at lower sintering temperature that causes the increase of mechanical properties at high temperature.

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Stabilization of thermal storage ceramics via the phase reconstruction of ferrotitanium slag and migration of Mg element
Mengting Jiang, Xiaopeng Li, Tengfei Deng
Journal of the American Ceramic Society.2025;[Epub] CrossRef
The influence of different additives on microstructure and mechanical properties of aluminum titanate ceramics
Weiwei Chen, Anze Shui, Qingliang Shan, Jiawei Lian, Cong Wang, Jianqiao Li
Ceramics International.2021; 47(1): 1169. CrossRef

The Effect of Sintering Processes and Additives on the Microstructures and Mechanical Properties of ZrB₂-SiC Composite Ceramics: Chang-Sup Kwon, Jung-Min Chae, Hyung-Tae Kim, Kyung-Ja Kim, Seong-Won Kim; J Korean Powder Metall Inst. 2011;18(6):562-567.; DOI: https://doi.org/10.4150/KPMI.2011.18.6.562

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This paper reports the effect of sintering processes and additives on the microstructures and mechanical properties of ZrB_2-SiC composite ceramics. We fabricated sintered bodies of ZrB_2-20 vol.% SiC with or without sintering additive, such as C or B_4C, densified by spark plasma sintering as well as hot pressing. While almost full densification was achieved regardless of sintering processes or sintering additives, significant grain growth was observed in the case of spark plasma sintering, especially with B_4C. With sintered bodies, mechanical properties, such as flexural strength and Vickers hardness, were also examined.

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Inter-laminar Strength of NITE-SiC/SiC Composites with Various Fiber Reinforcing Architecture
Jong-il Kim
Journal of Powder Materials.2024; 31(5): 437. CrossRef
Effect of the Size and Amount of SiC on the Microstructures and Thermal Conductivities of ZrB2-SiC Composite Ceramics
Seong-Won Kim, Chang-Sup Kwon, Yoon-Suk Oh, Sung-Min Lee, Hyung-Tae Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(5): 379. CrossRef

Phase Evolution and Thermo-physical Properties of La₂(Zr_1-xHf_x)₂O₇ Oxides for Thermal Barrier Coatings: Seong-Won Kim, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang; J Korean Powder Metall Inst. 2011;18(6):568-574.; DOI: https://doi.org/10.4150/KPMI.2011.18.6.568

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As operating temperatures of engines or turbines continually increase for higher efficiency, significant amounts of researches have been focused on finding new materials, which would be alternatives to conventional yttria-stabilized zirconia (YSZ) for thermal barrier coatings (TBCs). In this study, phase evolution and thermo-physical properties of La_2(Zr_1-xHf_x)_2O_7 pyrochlore systems are investigated for TBC applications. La_2(Zr_1-xHf_x)_2O_7 systems are comprised by selecting La3+ as A-site ions and Zr4+/Hf4+ as B-site ions in A_2B_2O_7 pyrochlore structures. For the developed phases in La_2(Zr_1-xHf_x)_2O_7 compositions, thermo-physical properties such as thermal conductivity, thermal expansion coefficient are examined. The potential of these La_2(Zr_1-xHf_x)_2O_7 compositions for TBC application is also discussed.

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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
Phase Evolution and Thermal Conductivities of (La1-xGdx)2Zr2O7Oxides for Thermal Barrier Coatings
Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seong Won Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(6): 429. CrossRef

Effect of MgO and NH₄OH on Formation of 5Mg(OH)₂·MgSO₄·3H₂O Whiskers: Ri Yu, Jae-Hwan Pee, Hyung-Tae Kim, Kyung-Ja Kim, Young-Woong Kim, Woong Kim, Yoo-Jin Kim; J Korean Powder Metall Inst. 2011;18(3):283-289.; DOI: https://doi.org/10.4150/KPMI.2011.18.3.283

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Magnesium hydroxide sulfate hydrate whiskers (5Mg(OH)_2cdotMgSO_4cdot3H_2O, abbreviated 513 MHSH) were prepared using hydrothermal reaction with magnesium oxide (MgO) and magnesium sulfate (MgSO_4cdot7H_2O) as the starting materials. The effects of the molar ratio of MgSO_4/MgO and amount of NH_4OH were studied. As a result, 513 MHSH whiskers co-existed with hexagonal plate Mg(OH)_2 at low concentration of SO_42-. The molar ratio of MgSO_4cdot7H_2O/MgO was 7:1, uniform 513 MHSH whiskers were formed without impurity such as Mg(OH)_2. Appropriate amount of NH_4OH has affected to formation of high quality MHSH. Their morphologies and structures were determined by powder X-ray diffraction (XRD) scanning electron microscopy (SEM) and thermo-gravimetric analyzer (TGA).

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Effect of sulfate ion on synthesis of 5 Mg(OH)2·MgSO4·3H2O whiskers using non-hydrothermal method with acid catalyst
Areum Choi, Nuri Oh, YooJin Kim
Journal of the Korean Ceramic Society.2022; 59(2): 224. CrossRef
Effect of H₂SO₄ and Reaction Time on Synthesis of 5Mg(OH)₂∙MgSO₄∙3H₂O Whiskers using Hydrothermal Reaction
Areum Choi, Nuri Oh, YooJin Kim
Journal of Korean Powder Metallurgy Institute.2020; 27(5): 401. CrossRef
Study of Fabrication and Improvement of Mechanical Properties of Mg-based Inorganic Fiber using Reflux Process and Silica Coating
Ri Yu, YooJin Kim
Journal of Korean Powder Metallurgy Institute.2019; 26(3): 195. CrossRef
Effect of MgSO4/MgO on the Synthesis of 5Mg(OH)2·MgSO4·3H2O Whiskers using One-step Ambient Pressure
Ri Yu, Jae-Hwan Pee, Hyung Tae Kim, YooJin Kim
Journal of the Korean Ceramic Society.2013; 50(3): 201. CrossRef

Phase Evolution and Thermo-physical Properties of Rare-earth Oxides for Thermal Barrier Systems: Byung-Chul Shim, Kil-Ho Kwak, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seong-Won Kim; J Korean Powder Metall Inst. 2010;17(2):148-153.; DOI: https://doi.org/10.4150/KPMI.2010.17.2.148

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Thermal barrier systems have been widely investigated over the past decades, in order to enhance reliability and efficiency of gas turbines at higher temperatures. Yttria-stabilized zirconia (YSZ) is one of the most leading materials as the thermal barriers due to its low thermal conductivity, thermodynamic stability, and thermal compatibility with metal substrates. In this work, rare-earth oxides with pyrochlore phases for thermal barrier systems were investigated. Pyrochlore phases were successfully formed via solid-state reactions started from rare-earth oxide powders. For the heat-treated samples, thermo-physical properties were examined. These rare-oxide oxides showed thermal expansion of 9sim12times10-6/K and thermal conductivity of 1.2~2.4 W/mK, which is comparable with the thermal properties of YSZ.

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Phase Evolution and Thermal Conductivities of (La1-xGdx)2Zr2O7Oxides for Thermal Barrier Coatings
Chang-Sup Kwon, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang, Seong Won Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(6): 429. CrossRef
Phase Evolution and Thermo-physical Properties of La2(Zr1-xHfx)2O7Oxides for Thermal Barrier Coatings
Seong-Won Kim, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Byung-Koog Jang
Journal of Korean Powder Metallurgy Institute.2011; 18(6): 568. CrossRef

A Study on Rheological Behavior of Cordierite Honeycomb Extrusion Paste: Yong-Ik Song, Hyung-Tae Kim, Jin-Gu Lee, Won-Jung Yoon, Sung-Soo Ryu; J Korean Powder Metall Inst. 2010;17(1):44-51.; DOI: https://doi.org/10.4150/KPMI.2010.17.1.044

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Abstract PDF: The rheological behavior of a cordierite honeycomb extrusion paste was investigated by measuring torque values in a Brabender plastograph. The extrusion pastes were formulated using binder (methy cellulose, MC), solvent (water), plasticizer (ploy ethylene glycol, PEG) and lubricants (oleic acid, OA). The mixing sequence and optimum organic binder, at least for homogeneous mixed state, can be determined from the rheological point of view. 3%MC-30%H_2O-1.5%PEG-1.0%OA with respect to the cordierite powder was chosen as a binder composition for the extrusion process of cordierite powder.

Fabrication of ZrB₂-based Composites for Ultra-high Temperature Materials: Seong-Won Kim, Jung-Min Chae, Sung-Min Lee, Yoon-Suk Oh, Hyung-Tae Kim, Sahn Nahm; J Korean Powder Metall Inst. 2009;16(6):442-448.; DOI: https://doi.org/10.4150/KPMI.2009.16.6.442

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ZrB_2-based composites are candidate materials for ultra-high temperature materials (UHTMs). ZrB_2 has become an indispensable ingredient in UHTMs, due to its high melting temperature, relatively low density, and excellent resistance to thermal shock or oxidation. ZrB_2 powders are usually synthesized by solid state reactions such as carbothermal, borothermal, or combined carbothermal reaction. SiC is added to this system in order to enhance the oxidation resistance of ZrB_2. In this study, ZrB_2?based composites were successfully synthesized and densified through two different processing paths. ZrB_2 or ZrB_2 25 vol.%SiC was fully synthesized from oxide starting materials with reducing agents after heat treatment at 1400°C. Besides, ZrB_2?20 vol.%SiC was fully densified with B_4C as a sintering additive after hot pressing at 1900°C. The synthesis mechanism and the effect of sintering additives on densification of ZrB_2 ?SiC composites were also discussed.

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The Effect of Sintering Processes and Additives on the Microstructures and Mechanical Properties of ZrB2-SiC Composite Ceramics
Chang-Sup Kwon, Jung-Min Chae, Hyung-Tae Kim, Kyung-Ja Kim, Seong-Won Kim
Journal of Korean Powder Metallurgy Institute.2011; 18(6): 562. CrossRef

Feasibility Test for Mechanical Property Characterization of BaTiO₃ Ceramics for MLCC Application Using Nanoindentation: Sung-Soo Ryu, Seong-Won Kim, Hyeong-Jun Kim, Hyung-Tae Kim; J Korean Powder Metall Inst. 2009;16(1):37-42.; DOI: https://doi.org/10.4150/KPMI.2009.16.1.037

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Abstract PDF: In this study, the feasible test for the mechanical property characterization of BaTiO_3 ceramics and multi-layer ceramic capacitor(MLCC) was performed with nanoindentation technique. In case of BaTiO_3 ceramics, hardness and elastic modulus are dependent on the densification of specimen showing the highest hardness and elastic modulus values of 12.3 GPa and 155 GPa, respectively at 1260°C. In case of MLCC chip, hardness of dielectric layer was lower than that of margin region. The nanoindentation method could be useful tool for the measurement of mechanical property within BaTiO_3 dielectric layer of very thin thickness in high capacitance MLCC.

Characterization of Ti(C,N) Solid Solutions in Densified Ti(C,N) and TiC-TiN-Ni Cermet: Seong-Won Kim, Jung-Min Chae, Shin-Hoo Kang, Sung-Soo Ryu, Hyung-Tae Kim; J Korean Powder Metall Inst. 2008;15(6):503-508.; DOI: https://doi.org/10.4150/KPMI.2008.15.6.503

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Ti(C,N) solid solutions in hot-pressed Ti(C_xN_1-x) (x=0.0, 0.3, 0.5, 0.7, 1.0) and 40TiC-40TiN-20Ni (in wt.%) cermet were characterized in this study. For hot-pressed Ti(C,N)s, the lattice parameters and hardness values of Ti(C,N) were determined by using XRD (X-Ray Diffraction) and nanoindentation. The properties of hot-pressed Ti(C,N) samples changed linearly with their carbon or nitrogen contents. For the TiC-TiN-Ni cermet, the hardness of the hard phase and binder phase were determined by nanoindentation in conjunction with microstructural observation. The measured hardness values were sim8.7 GPa for the binder phase and sim28.7 GPa for the hard phase, which was close to the hardness of hot-pressed Ti(C_0.7N_0.3).

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Sintering Behavior and Mechanical Property of Transition Metal Carbide-Based Cermets by Spark Plasma Sintering
Jeong-Han Lee, Hyun-Kuk Park, Sung-Kil Hong
Korean Journal of Materials Research.2022; 32(1): 44. CrossRef

Measurement of Hardness of Constituent Phases in Ti(C_0.7N_0.3)-NbC-Ni Cermets Using Nanoindentation: Seong-Won Kim, Dae-Min Kim, Shin-Hoo Kang, Sung-Soo Ryu, Hyung-Tae Kim; J Korean Powder Metall Inst. 2008;15(6):482-488.; DOI: https://doi.org/10.4150/KPMI.2008.15.6.482

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Abstract PDF: The indentation technique has been one of the most commonly used techniques for the measurement of the mechanical properties of materials due to its experimental ease and speed. Recently, the scope of indentation has been enlarged down to the nanometer range through the development of instrumentations capable of continuously measuring load and displacement. In addition to testing hardness, the elastic modulus of submicron area could be measured from an indentation load-displacement (P-h) curve. In this study, the hardness values of the constituent phases in Ti(C_0.7N_0.3)-NbC-Ni cermets were evaluated by nanoindentation. SEM observation of the indented surface was indispensable in order to separate the hardness of each constituent phase since the Ti(C_0.7N_0.3)-based cermets have relatively inhomogeneous microstructure. The measured values of hardness using nanoindentation were sim20 GPa for hard phase and sim10 GPa for binder phase. The effect of NbC addition on hardness was not obvious in this work.

Sintering Behavior of Nano-sized Gd₂O₃-doped CeO₂ Powder Prepared by A High Energy Ball Milling: Sung-Soo Ryu, Hyung-Tae Kim; J Korean Powder Metall Inst. 2008;15(4):302-307.; DOI: https://doi.org/10.4150/KPMI.2008.15.4.302

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Gd_2O_3-doped CeO_2(GDC) solid solutions have been considered as a promising materials for electrolytes in intermediate-temperature solid oxide fuel cells. In this study, the nano-sized GDC powder with average panicle size of 69nm was prepared by a high energy ball milling process and its sintering behavior was investigated. Heat-treatment at 1200°C of nano-sized GDC powder mixture led to GDC solid-solution. The enhanced densification over 96% of relative density was obtained after sintering at 1300°C for 2h. It was found that the sinterability of GDC powder could be significantly improved by the introduction of a high energy ball milling process.

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Synthesis of Nanocrystalline BaTiO3Powder by the Combination of High Energy Ball Milling of BaCO3-TiO2Mixture and Solid-State Reaction
Sung-Soo Ryu
Journal of Korean Powder Metallurgy Institute.2012; 19(4): 310. CrossRef

Measurement of High Temperature Dielectric Property at Microwave Frequency Using Cavity Perturbation Method: Dong-Eun Kim, Jin-Ho Jung, Sung-Min Lee, Hyung-Tae Kim; J Korean Powder Metall Inst. 2006;13(6):455-461.; DOI: https://doi.org/10.4150/KPMI.2006.13.6.455

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High temperature dielectric constants of the various ceramic materials have been measured using cavity perturbation method. The measurements were applied to refractory, traditional and fine ceramic powder compacts from room temperature to 1200°C. Calibration constant in the equation suggested by Hutcheon et al., was determined from the dielectric constants of reference specimen (teflon and alumina) at room temperature. From these results, informations on the refectory materials were obtained for the microwave kiln design and understanding of the microwave heating effects of ceramics have been improved.

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Dielectric Properties of β-SiAlON at High Temperature Using Perturbation Method
Young Hoon Seong, Ha Neul Kim, Do Kyung Kim
Key Engineering Materials.2008; 403: 121. CrossRef

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