• 제목/요약/키워드: Ceramic materials

검색결과 5,130건 처리시간 0.032초

Effect of Silicon Nitride Whisker Content on the Flexural Strength of Silicon Nitride-Boron Nitride-Silicon Carbide Multi-Layer Composites

  • Park, Dong-Soo;Cho, Byung-Wook
    • 한국세라믹학회지
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    • 제40권9호
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    • pp.832-836
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    • 2003
  • Multi-layer ceramic composites were prepared by tape casting followed by hot pressing using silicon nitride layer with silicon nitride whiskers, silicon nitride layer with silicon carbide particles and boron nitride-alumina layer. The whiskers were aligned during the casting. As the whisker content of the silicon nitride layer was increased up to 10 wt%, the flexural strength of the multi-layer composite was increased. However, further increase of the whisker content in the layer resulted in a rapid decrease of the strength of the composite. The results suggest that the strength of multi-layer ceramic composite showing non-catastrophic failure behavior can be significantly improved by incorporating the aligned whiskers in the layers.

Regression Analysis on the Effect of Compressive Grinding of Cement Raw Materials and Clinker Granule

  • Kim, Jong-Cheol;Auh, Keun-Ho
    • The Korean Journal of Ceramics
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    • 제6권2호
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    • pp.96-99
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    • 2000
  • Particle size of the cement raw materials is important not only in clinker burning but also in cement productivity. Model experiment was designed to investigate the effect of compressive grinding on cement raw materials and clinker granule. Compressive grinding was more efficient in reducing hard materials like quartz. Regression model was constructed to explain the effect of compressive grinding on the size reduction of cement raw materials and clinker.

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The effect of the initial BSCCO 2212 grain size on the final grain size and the formation of BSCCO 2223

  • Yoo, Jai-Moo;Park, Myoung-Je;Kim, Hai-Doo;Chung, Hyung-Sik;Ko, Jae-Woong
    • 한국초전도학회:학술대회논문집
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    • 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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    • pp.285-288
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    • 2000
  • The effect of the initial BSCCO 2212 grain size on the final gain size and the formation of the BSCCO 2223 was studied using a powder precursor synthesized by two-powder method. 2212 and CaCuO$_2$ tapes were prepared by dip coating and joined by pressing and then followed by the repeated thermo mechanical treatment. The samples were characterized by XRD and SEM analysis. The formation and grain size of the BSCCO 2223 depended on the initial BSCCO 2212 grain size.

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Scf 파라메타에 의한 세라믹 마멸 평가 (The Assessment of Ceramic Wear by the Parameter Scf)

  • 김상우;김석삼
    • Tribology and Lubricants
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    • 제12권1호
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    • pp.56-65
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    • 1996
  • The result of wear test for ceramic materials was assessed by Scf parameter to verify the usefulness of the proposed Scf parameter. Friction and wear tests were carried out with ball on disk type. The materials used in this study were HIPed Alumina $(Al_2O_3)$, Silicon carbide (sic), Silicon nitride $(Si_3N_4)$ and Zirconia $(ZrO_2)$. The tests were carried out at room temperature with self mated couples of ceramic materials under lubricated condition. Turbine oil was used as a lubricant. In this test, increasing the load, specific wear rates and wear coefficients of four kinds of ceramic materials had a tendency to increase. The wear coefficients of ceramic materials were in order of $Al_2O_3, SiC, Si_3N_4, ZrO_2$. Worn surfaces investigated by SEM had residual surface cracks and wear particles caused by brittle fracture. As the fracture toughness of ceramic materials was higher, wear resistance more increased. The roughness of worn surface had correlation with wear rate. The wear rate(W$_{s}$) and Scf parameter showed linear relationship in log-log coordinates and the wear equation was given as $W_s = 5.52 $\times$ Scf^{5.01}$.

The R & D of SiC Fiber Reinforced Composites for Energy and Transportation Applications

  • Kohyama, Akira
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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    • pp.5-13
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    • 2006
  • Based on the inventions of continuous ceramic fibers, such as C, SiC, $Al_2O_3$ etc., by polymer precursor driven methods, there have been many efforts to fabricate ceramic continuous fiber reinforced composite materials with metals and ceramics matrices. The main purpose of the R & D efforts has been to produce materials for severe environments, including advanced energy systems, advanced transportation systems. The efforts have been started from the R & D of metal matrix composite materials and now the strong emphasis on ceramic matrix composites R & D can be recognized. This paper provides a brief review about the national efforts to establish advanced composite materials for future industries starting from mid 70s. C/Al and SiC/Al are the typical examples to be applied transportation systems and energy systems. The excellences in specific strength and overall mechanical properties, the excellences in environmental resistance make those materials as potential materials for advanced ocean construction and marine transportation systems. About the recent progress in ceramic fiber reinforced ceramic composites, advanced SiC/SiC composites including NITE-SiC/SiC will be introduced and the present status will be introduced.

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