• Title/Summary/Keyword: 방전 플라즈마 소결

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The Sintering Behavior of $ZrB_2$-ZrC Composites Sintered by Spark Plasma Sintering Process (방전플라즈마 소결법에 의한 $ZrB_2$-ZrC 복합체의 소결 거동)

  • 심광보;김경훈
    • Journal of the Korean Ceramic Society
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    • v.38 no.6
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    • pp.582-586
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    • 2001

  • 방전 플라즈마 소결법을 이용하여 ZrB$_2$-ZrC 복합체를 소결하여 소결 거동과 미세구조에 대하여 조사하였다. 소결 조제로서 란타늄을 첨가하였을 경우에 첨가하지 않았을 경우보다 더 낮은 온도에서 소결 수축이 시작되었으며, 180$0^{\circ}C$에서 거의 치밀화가 완성되었다. 란타늄은 방전플라즈마 소결시 초기 분말 간 액상 형성으로 물질이동을 가속화하여 ZrB$_2$-ZrC 복합체의 치밀화에 커다란 기여를 하며, 냉각 시에 재결정화하여 결정립계와 결정립 삼중점에 란타늄이 포함된 이차상을 형성하는 것으로 확인되었다. 또한 ZrB$_2$-ZrC는 강한 공유결합성 재료임에도 불구하고 미세 구조 내에 잘 발달된 전위 구조를 형성하고 있음을 확인하였다.

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Characteristics of Grain Orientation and Grain Boundaries of the $ZrB_2$-ZrC Composites Densified by Spark Plasma Sintering (방전플라즈마소결법으로 제조된 $ZrB_2$-ZrC 복합체의 결정립 방위분포 및 결정입계의 특성)

  • Shim, Seung-Hwan;Kim, Kyoung-Hun;Shim, Kwang-Bo
    • Journal of the Korean Ceramic Society
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    • v.38 no.10
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    • pp.914-920
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    • 2001

  • The grain orientation distribution and grain boundary characterization of $ZrB_2$-ZrC composites sintered by a SPS(Spark Plasma Sintering) method, a new sintering technique were analyzed by the EBSP technique and then their crystallographic results have been compared with those of a sintered specimen using a PLS(Pressureless Sintering) method. In the $ZrB_2$-ZrC composite manufactured by SPS, (0001) planes of $ZrB_2$ were oriented in the direction normal to the specimen surface. In the case of PLS, those of $ZrB_2$ were oriented normal to the electron beam. In both cases of PLS and SPS, ZrC grains had the randomly oriented grain structure. The grain boundary characterization showed that low angle grain boundaries in the PLS and SPS processed materials constituted about 10% and 8% of the total number of boundaries, respectively, represented the only slight difference between the proportion of low angle grain boundary. However, in the distribution of CSL(Coincident Site Lattice) boundaries, it was shown the higher proportion of CSL boundaries with $\Sigma$ 3,5,7,9, 11 in the SPS processed material.

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Mechanical properties of $B_4C$ ceramics fabricated by a spark plasma sintering process (방전플라즈마 소결법을 이용한 고밀도 탄화 붕소 제조 및 기계적 특성)

  • Kim, Kyoung-Hun;Chae, Jae-Hong;Park, Joo-Seok;Kim, Dae-Keun;Shim, Kwang-Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.17 no.3
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    • pp.128-132
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    • 2007

  • [ $B_4C$ ] ceramics were fabricated by spark plasma sintering process and their sintering behavior, microstructure and mechanical properties were evaluated. Relative density of $B_4C$ ceramics were obtained by spark plasma sintering method reached as high as 99% at lower temperature than conventional sintering method, in addition, without any sintering additives. The mechanical properties of $B_4C$ ceramics was improved by a methanol washing process which can be removed $B_2O_3$ phase from a $B_4C$ powder surface. This improvement results ken the formation of homogeneous microstructure because the grain coarsening was suppressed by the elimination of $B_2O_3$ phase. Particularly, fracture toughness of the sintered specimen using a methanol washed powder improved over 30% compared with the specimen using an as-received commercial powder.

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