• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.127.1-127.1
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• 2010

고체산화물연료전지는 고효율 및 무공해의 전기화학 에너지 변환장치로서, 최근 국내외에서 활발한 연구개발이 수행되고 있다. 특히, 고체산화물 연료전지 시스템의 조기 상용화를 위해 시스템의 작동온도를 약 $800^{\circ}C$ 이하로 낮추고 저가로 생산 할 수 있는 제조공정 개발에 대한 연구를 적극적으로 수행하고 있다. 본 연구에서는 고체산화물연료전지의 단위셀를 구성하는 연료극지지체 및 박막 전해질에 대해서 저가 양산의 테이프케스팅법 및 동시소성 공정, 그리고 연료극 지지체 전해질(anode-supported electrolyte)에 대한 공기극 페이스트 프린팅 제조공정에 대해 소개한다. 또한 고체산 화물연료전지의 제조공정 및 시간을 단축하기 위해 방전플라즈마 소결공법(SPS)에 의한 연료극 지지체 제조 공정, 단위셀의 성능 최적화를 위한 나노 스케일의 고성능 전해질 소재 분말합성 공정(crystallite size: 5~10nm, surface area : $100m^2/g$ 이상) 그리고 테이프케스팅에 의한 박막 전해질 제조 공정(thin film : $10{\mu}m$ 이하) 등 주요 단위셀 소재 및 부품의 제조공정 특성 그리고 단위셀의 전기화학적 특성(max. power density : 1.0 W/$cm^2$)에 대해 소개하며, 최종적으로 평판형 대면적 고체산화물연료전지(max. $20cm{\times}15cm$)의 단위셀 상용화 제조 기술 및 성능평가 기술에 대해서도 소개 할 예정이다.

• 한국결정성장학회지
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• 제13권6호
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• pp.309-314
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• 2003

방전 플라즈마 소결법을 적용하여 $Al_2O_3$-SiC 나노 복합체를 150$0^{\circ}C$ 이하의 온도에서 완전치밀화를 이루었다. 제조된 $Al_2O_3$-SiC 복합체는 이상 결정립 성장 없이 매우 균질한 미세구조를 형성하고 있는데, 첨가된 SiC 입자는 주로 결정립 내 및 결정립계에 존재하면서 $Al_2O_3$기지상에서 결정립 성장을 억제하는데 매우 유호하였음을 확인 할 수 있다. 한편, SiC 입자의 첨가는 크랙 회절 및 브릿징 등에 의해서 유도된 재료 강도 및 인성 강화 기구에 의해서 $Al_2O_3$-SiC 복합체의 기계적 물성을 크게 향상시켰다.

• 한국분말재료학회지
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• 제19권2호
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• pp.105-109
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• 2012

Magnetic properties and the microstructures of magnets prepared by spark plasma sintering were investigated in order to enhance magnetic properties by grain size control. Nd-Fe-B magnets were fabricated by the spark plasma sintering under 30 MPa at various temperatures. The grain size was effectively controlled by the spark plasma sintering and it was possible to make Nd-Fe-B magnets with grain size of 5.9 ${\mu}m$.

• 한국재료학회지
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• 제18권7호
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• pp.357-361
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• 2008

Microstructure and mechanical properties of WC-3 wt% Co cemented carbides, fabricated by a spark plasma sintering (SPS) process, were investigated in this study. The WC-3 wt%Co powders were sintered at $900{\sim}1100^{\circ}C$ for 5min under 40MPa in high vacuum. The density and hardness were increased as the sintering temperature increased. WC-3 wt%Co compacts with a relative density of 97.1% were successfully fabricated at $1100^{\circ}C$. The fracture toughness and hardness of a compact sintered at $1100^{\circ}C$ were $21.6 MPa{\cdot}m^{1/2}$ and 4279 Hv, respectively.

• 한국기계가공학회지
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• 제12권6호
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• pp.3-9
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• 2013

Aluminum Oxide($Al_2O_3$) ceramics are excellent candidates for such applications due to their outstanding mechanical, thermal, and tribological properties. However, they are difficult to machine using conventional mechanical methods. Carbon fillers, such as carbon nanotubes(CNT) and graphene nanoplatelets(GNP)can be dispersed in a ceramic matrix to improve the mechanical and electrical properties. In this study, CNT and Graphene reinforced hybrid ceramic composites were fabricated using the spark plasma sintering method at a temperature of $1,500^{\circ}C$, pressure of 40 MPa, and soaking time of 10min. Besides this, the material properties such as microstructure, crystal structure, hardness, and electrical conductivity were analyzed using FE-SEM, XRD, Vickers, and the 4-point probe method. A micro machining test was carried out to compare the effects of the material properties and the machining performance for CNT and Graphene reinforced ceramic composites.

• 한국분말재료학회지
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• 제7권3호
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• pp.161-167
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• 2000

Mechanically-alloyed NiAl powder and ball-milled (Ni+Al) powder mixture were sintered by spark-plasma sintering(SPS) process. Mechanical alloying was performed in a horizontal attritor for 20 h with rotation speed of 600 rpm. (Ni+Al) powder mixtures were prepared by ball milling for 1 and 10 h with 120 rpm. Both powders were sintered at $1150^{\circ}C$ for 5 min under $10^{-3}$ torr vacuum with 50 MPa die pressure in a SPS facility. Sintered densities of 97% and 99% were obtained from mechanically-alloyed NiAl powder and (Ni+Al) powder mixture, respectively. The sintered compact of (Ni+Al) powder mixture showed large grain size by a very rapid grain growth, while the grain size of mechanically-alloyed NiAl powder compact after sintering was extremely fine(80 nm). The difference in densification behavior of both powders were discussed.

• 한국결정성장학회지
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• 제34권4호
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• pp.125-130
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• 2024

헤마타이트와 순금속 Mg 분말에 대하여 볼밀링법을 이용하여 강자성 분말재료를 제조하였으며, 얻어진 분말시료를 800-1,000℃에서 방전플라즈마 소결법을 이용하여 벌크화를 실시하였다. 헤마타이트와 순금속 Mg의 혼합분말을 볼밀링 처리한 결과, 1시간 이전에 강자성 Fe-MgO 복합분말을 얻을 수 있었다. 얻어진 시료의 자화값 및 보자력은 볼밀링 처리 중 헤마타이트와 순금속 Mg의 고상반응에 의하여 변화하였는데, 포화자화 값은 볼밀링 시간에 따라 증가하여 5시간 후에 93.4 emu/g을 나타내었다. 볼밀링 5시간 시료는 방전플라즈마 소결 시 300℃ 이상에서 급격히 수축이 발생한 후 800℃까지 서서히 수축이 진행됨을 알 수 있었다. XRD 피크의 반가폭을 이용한 hall-plot으로부터 900℃에서 소결된 Fe-MgO 벌크체의 Fe 평균 결정립 크기는 50 nm 이었다. 또한 이 벌크시료의 보자력은 90 Oe로 여전히 높은 값을 보였는데 이것은 강자성 Fe 상의 결정립 성장이 소결과정 중에 억제되었기 때문인 것으로 판단된다.

• 한국분말재료학회지
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• 제22권3호
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• pp.175-180
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• 2015

In this study, ternary compound Max Phase $Ti_2AlC$ material was mixed by 3D ball milling as a function of ball milling time. More than 99.5 wt% pure $Ti_2AlC$ was synthesized by using spark plasma sintering method at 1000, 1100, 1200, and $1300^{\circ}C$ for 60 min. The material characteristics of synthesized samples were examined with relative density, hardness, and electrical conductivity as a function of sintering temperature. The phase composition of bulk was identified by X-ray diffraction. On the basis of FE-SEM result, a terraced structures which consists of several laminated layers were observed. And $Ti_2AlC$ bulk material obtained a vickers hardness of 5.1 GPa at the sintering temperature of $1100^{\circ}C$.

• 한국분말재료학회지
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• 제22권3호
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• pp.157-162
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• 2015

SKD11(ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. Adding of CNTs increased the performance of mechanical properties more. 1, 3 vol.% CNTs was dispersed in SKD11 matrix by mechanical alloying. SKD11 carbon nanocomposite powder was sintered by spark plasma sintering process. FE-SEM, HR-TEM and Raman analysis were carried out SKD11 carbon nanocomposites.

• 한국재료학회지
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• 제17권6호
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• pp.331-336
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• 2007

The pure Mg powder compacts were successfully fabricated using SPS process. The machined chip powder showed flake shaped morphology with coarse surfaces, while gas atomized powders were spherical in morphology with smooth surfaces. In this study, SPS process was used to consolidate the pure Mg powder because this process allows high density consolidation in a short time. The results showed that increased sintering temperature from $350^{\circ}C$ to $500^{\circ}C$ with pressure of 30MPa, the maximum values of the density was increased from 98.1% to 99.8% of theoretical density, respectively. However, density of the sintered chip powders was higher than that of gas-atomized powder due to larger contact areas between particles.