• Title/Summary/Keyword: 방전플라즈마소결

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Fabrication of 8YSZ-$Al_2O_3$ solid oxide full cell (SOFC) electrolyte by a spark plasma sintering method (방전 플라즈마 소결법을 이용한 8YSZ-$Al_2O_3$ 고체 산화물 연료전지 전해질 제조)

  • Kim Jae Kwang;Choi Bong Geun;Yang Jae Kyo;Choa Yong Ho;Shim Kwang Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.1
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    • pp.16-20
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    • 2005

  • In order to improve electrical conductivity and mechanical properties of 8YSZ SOFC electrolyte material, we used Al₂O₃ as an additive and applied the spark plasma sintering (SPS) method. The sintered bodies were densified above 96 ％ of theoretical density at 1200℃ and possessed microstructures composed of homogeneous grains less than 1 ㎛ in size. The addition of Al₂O₃ improved fracture toughness and bending strength by inhibiting grain growth of 8YSZ and increased total ionic conductivity because grain interior conductivity appeared to remain constant and grain boundary conductivity increased. It was assumed that the dissolution of Al₂O₃ into 8YSZ which was inevitable problem at commercial sintering method was effectively prohibited by the SPS technique with a relatively low sintering temperature and the reaction between Al₂O₃ and SiO₂ present at grain boundary to produce the crystalline Al/sub 2-x/Si/sub l-y/O/sub 5/ phase, resulting in the increase of grain boundary conductivity.

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Sintering Characteristics of ZnO Fabricated by Spark Plasma Sintering Process for High Temperature Thermoelectric Materials Application (고온용 ZnO계 열전 재료의 방전플라즈마 소결 특성 및 미세구조)

  • 심광보;김경훈;홍영호;채재홍
    • Journal of the Korean Ceramic Society
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    • v.40 no.6
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    • pp.560-565
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    • 2003

  • M-doped (M=Al, Ni) ZnO thermoelectric materials were fully densified at low temperatures of 800∼1,000$^{\circ}C$ and their sintering characteristics and microstructural features were investigated. Electron microscopic analysis showed that the addition of NiO promoted tile formation of solid solution and caused actively grain growth. The addition of A1$_2$O$_3$ prevented the evaporation of pure ZnO at grain boundaries and suppressed the grain growth by the formation of secondary phase. In case of the addition of A1$_2$O$_3$ together with NiO, the specimen showed an excellent microstructure and also the SEM-EBSP (Electron Back-scattered Diffraction Pattern) analysis confirmed that it shows a superior grain boundary distribution to the others specimens. These microstructural characteristics induced by the addition of A1$_2$O$_3$ together with NiO may increase the electrical conductivity by the increase in carrier concentration and decrease the thermal conductivity by the phonon scattering effect and, consequently, improve the thermoelectric property.

  • https://doi.org/10.4191/KCERS.2003.40.6.560 인용 PDF KSCI

Thermoelectric characteristics of the spark plasma-sintered silicon boride ceramics (방전 플라즈마 소결법으로 제조된 silicon boride 세라믹스의 열전 특성)

  • Shim, Seung-Hwan;Lee, Dae-Woong;Chae, Jae-Hong;Matsushita, Jun-Ichi;Shim, Kwang-Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.2
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    • pp.75-78
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    • 2005

  • Silicon boride ($SiB_6$) is very promising for use as thermoelectric materials at high temperature because of its high melting point and relatively large Seebeck coefficient. In the present work, spark plasma sintering (SPS) was applied for preparing dense $SiB_6$ ceramics, and their thermoelectric properties were investigated, together with their microstructural evaluation. The SPS process was found to be effective in densifying a $SiB_6$ ceramic, typically 99 % of the theoretical density at low temperature of $1500^{\circ}C$. In comparison with $SiB_6$ specimen prepared by hot-pressing, the SPS-processed specimen exhibited the significantly improved Seebeck coefficient, resulting in the higher power factor.

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