• Title, Summary, Keyword: SiC

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Fabrication of SiC/SiC Composites by Reaction Sintering Process (반응소결법에 의한 SiC/SiC 복합재료의 제조)

  • Lee, S.P.;Yoon, H.K.;Kohyama, A.
    • Proceedings of the KSME Conference
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    • pp.27-31
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    • 2001
  • Hi-Nicalon SiC fiber reinforced SiC composites (SiC/SiC) have been fabricated by the reaction sintering process. Braided Hi-Nicalon SiC fiber with double interphases of BN and SiC was used in this composite system. The microstructures and the mechanical properties of reaction sintered SiC/SiC composites were investigated through means of electron microscopies (SEM, TEM, EDS) and bending tests. The matrix morphology of reaction sintered SiC/SiC composites was composed of the SiC phases that the composition of the silicon and the carbon is different. The TEM analysis showed that the residual silicon and the unreacted carbon were finely distributed in the matrix region of reaction sintered SiC/SiC composites. Reaction sintered SiC/SiC composites also represented proper flexural strength and fracture energy, accompanying the noncatastrophic failure behavior.

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Interface formation and thermodynamics between SiC and thin metal films (SiC와 금속박막간의 계면형성 및 열역학)

  • Chang-Sung Lim;Kwang-Bo Shim;Dong-Woo Shin;Keun-Ho Auh
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.1
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    • pp.62-72
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    • 1996
  • The interface formation and reaction-product morphology between SiC and thin metal films were studied at temperatures between 550 and $1450^{\circ}C$ for various times. The typical reaction layer sequence was CoSi/CoSi+C/CoSi/CoSi+C/ $\cdots$ /SiC reaction at 1050 and $1250^{\circ}C$ for 2 h, while $Ni_2Si/Ni_2Si+C/Ni_2Si/Ni_2Si+C/ {\cdots} /SiC$ at 950 and 105$0^{\circ}C$ for 2 h. Carbon precipitated preferentially on the outer surface and crystallized as graphite above $1450^{\circ}C$ for SiC/Co reaction zone and $1250^{\circ}C$ for SiC/Ni. The mechanism of the periodic band structure formation with carbon precipitation behaviour was discussed in terms of thermodynamic considerations.

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Property Evaluation of Reaction Sintered SiC/SiC Composites Fabricated by Melt Infiltration Process (용융함침법에 의한 반응소결 SiC/SiC 복합재료의 특성 평가)

  • Lee, Sang-Pill;Shin, Yun-Seok;Kohyama, Akira
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.2
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    • pp.205-210
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    • 2007
  • SiC/SiC composites and monolithic SiC materials have been fabricated by the melt infiltration process, through the creation of crystallized SiC phase by the chemical reaction of C and Si. The reinforcing material used in this system was a braided Hi-Nicalon SiC fiber with double interphases of BN and SiC. The microstructures and the mechanical properties of RS-SiC based materials were investigated through means of SEM, TEM, EDS and three point bending test. The matrix morphology of RS-SiS/SiC composites was greatly composed of the SiC phases that the chemical composition of Si and C is different. The TEM analysis showed that the crystallized SiC phases were finely distributed in the matrix region of RS-SiC/SiC composites. RS-SiC/SiC composites also represented a good flexural strength and a high density, accompanying a pseudo failure behavior.

Current Status of $SiC_{f}/SiC$ Composites Material in Fusion Reactor

  • Yoon, Han-Ki;Lee, Sang-Pill
    • Proceedings of the KSME Conference
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    • pp.166-171
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    • 2007
  • The characterization of monolithic SiC and SiCf/SiC composite materials fabricated by NITE and RS processes was investigated in conjunction with the detailed analysis of their microstructure and density. The NITE-SiC based materials were fabricated, using a SiC powder with average size of 30 nm. RS- SiCf/SiC composites were fabricated with a complex slurry of C and SiC powder. In the RS process, the average size of starting SiC particle and the blending ratio of C/SiC powder were $0.4\;{\mu}m$ and 0.4, respectively. The reinforcing materials for /SiC composites were BN-SiC coated Hi-Nicalon SiC fiber, unidirectional or plain woven Tyranno SA SiC fiber. The characterization of all materials was examined by the means of SEM, EDS and three point bending test. The density of NITE-SiCf/SiC composite increased with increasing the pressure holding time. RS-SiCf/SiC composites represented a great decrease of flexural strength at the temperature of $1000\;^{\circ}C.$

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Fabrication of Reaction Sintered SiC Materials by Complex Slurry with Nano Size Particles (나노입자 혼합 복합슬러리를 이용한 반응소결 SiC 재료의 제조)

  • Lee Sang-Pill
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.3
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    • pp.425-431
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    • 2005
  • The efficiency of complex slurry preparation route for developing the high performance SiC matrix of $RS-SiC_{f}/SiC$ composites has been investigated. The green bodies for RS-SiC materials prior to the infiltration of molten silicon were prepared with various C/SiC complex slurries, which associated with both the sizes of starting SiC particles and the blending conditions of starting SiC and C particles. The characterization of Rs-SiC materials was examined by means of SEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, the process optimization is also discussed. The flexural strength of Rs-SiC materials greatly depended on the content of residual Si. The decrease of starting SiC particle size in the C/SiC complex slurry was effective for improving the flexural strength of RS-SiC materials.

Surface structure and critical load of thin metal films on SiC substrate (SiC 기판상의 금속박막의 표면구조 및 임계하중)

  • 임창성
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.5 no.4
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    • pp.358-369
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    • 1995
  • Surface structure and adhesion by the reaction between thin metal films and SiC were studied at temperatures between 550 and $1450^{\circ}C$ for various times. The reaction with the formation of various silicides was initially observed above $850^{\circ}C$ for SiC/Co system and $650^{\circ}C$ for SiC/Ni system. The cobalt reacted with SiC and consumed completely at $1050^{\circ}C$ for 0.5 h and the nickel at $950^{\circ}C$ for 2 h. The observed CoSi phase in SiC/Co and Ni$_2$Si phase in SiC/Ni are thermodynamically stable in the reaction zone up to 125$0^{\circ}C$ and $1050^{\circ}C$ respectively. Carbon was crystallized as graphite above $1450^{\circ}C$ for SiC/Co reaction surface and $1250^{\circ}C$ for SiC/Ni. The critical loads of the thin metal films on SiC substrate were qualitatively compared in terms of the scratch test method. At temperatures between 850 and $1050^{\circ}C$, relatively higher values of 20~33 N were observed for SiC/Ni couples.

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A Study on SiC/SiC and SiC/Mild steel brazing by the Ag-Ti based alloys (Ag-Ti계 합금을 사용한 SiC/SiC 및 SiC/연강 브레이징에 대한 연구)

  • 이형근;이재영
    • Journal of Welding and Joining
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    • v.14 no.4
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    • pp.99-108
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    • 1996
  • The microstructure and bond strength are examined on the SiC/SiC and SiC/mild steel joints brazed by the Ag-Ti based alloys with different Ti contents. In the SiC/SiC brazed joints, the thickness of the reaction layers at the bond interface and the Ti particles in the brazing alloy matrices increase with Ti contents. When Ti is added up to 9 at% in the brazing alloy. $Ti_3SiC_2$ phase in addition to TiC and $Ti_5Si_3$ phase is newly created at the bond interface and TiAg phase is produced from peritectic reaction in the brazing alloy matrix. In the SiC/mild steel joints brazed with different Ti contents, the microstructure at the bond interface and in the brazing alloy matrix near SiC varies similarly to the case of SiC/SiC brazed joints. But, in the brazing alloy matrix near the mild steel, Fe-Ti intermetallic compounds are produced and increased with Ti contents. The bond strengths of the SiC/SiC and SiC/mild steel brazed joints are independent on Ti contents in the brazing alloy. There are no large differences of the bond strength between SiC/SiC and SiC/mild steel brazed joints. In the SiC/mild steel brazed joints, Fe dissolved from the mild steel does not affect on the bond strength of the joints. Thermal contraction of the mild steel has nearly no effects on the bond strength due to the wide brazing gap of specimens used in the four-point bend test. The brazed joints has the average bond strength of about 200 MPa independently on Ti contents, Fe dissolution and joint type. Fracture in four-point bend test initiates at the interface between SiC and TiC reaction layer and propagates through SiC bulk. The adhesive strength between SiC and TiC reaction layer seems to mainly control the bond strength of the brazed joints.

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Effect of SiC Particle Size on Microstructure of $Si_3N_4/SiC$ Nanocomposites ($Si_3N_4/SiC$ 초미립복합체의 미세조직에 미치는 SiC 입자크기의 영향)

  • 이창주;김득중
    • Journal of the Korean Ceramic Society
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    • v.37 no.2
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    • pp.152-157
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    • 2000
  • Si3N4/SiC nanocomposite ceramics containing 5 wt%dispersed SiC particles were prepared by gas-pressure-sintering at 200$0^{\circ}C$ under nitrogen atmosphere. SiC particles with average sizes of 0.2 and 0.5${\mu}{\textrm}{m}$ were used, and the effect of the SiC particle size on the microstructure was investigated. The addition of SiC particles effectively suppressed the growth of the Si3N4 matrix grains. The effect of grain growth inhibition was higher in the nanocomposites dispersed with fine SiC. SiC particles were dispersed uniformly inside Si3N4 matrix grains and on grain boundaries. When the fine SiC particles were added, large fraction of the SiC particles was trapped inside the grains. On the other hand, when the large SiC particles were added, most of the SiC particles were located on grain boundaries. Typically, the fraction of SiC particles located at grain boundaries was higher in the specimen prepared from $\beta$-Si3N4 than in the specimen prepared from $\alpha$-Si3N4.

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Growth of SiC film on SiNx/Si Structure (SiNx/Si 구조를 이용한 SiC 박막성장)

  • Kim, Gwang-Cheol;Park, Chan-Il;Nam, Gi-Seok;Im, Gi-Yeong
    • Korean Journal of Materials Research
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    • v.10 no.4
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    • pp.276-281
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    • 2000
  • Silicon carbide(SiC) films were grown on modified Si(111) surface with a SiNx in the NH$_3$surrounding. Thickness of SiC films was decreased with increasing of the nitridation time. Also, voids having crystal defects were removed at interface of SiC/Si according to growth parameters. SiC films were grown on SiNx/Si substrate of 100, 300 and 500nm thickness. SiC films were deposited along [111] direction and columnar grains of SiC crystal. The void-free film was observed in the interface of SiC/SiNx. This result suggests that fabrication of SiC devices are applied to SiNx replacing silicon oxide in SOI structure.

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CHARACTERIZATION OF MONOLITHIC RS-SiC AND RS-$SiC_f/SiC$ COMPOSITE MATERIALS (반응소결 SiC 재료와 $SiC_f/SiC$ 복합재료의 특성)

  • Jin, Joon-Ok;Lee, Sang-Pill;Lee, Jin-Kyung;Yoon, Han-Ki;Khoyama, Akira
    • Proceedings of the KSME Conference
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    • pp.376-380
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    • 2003
  • The microstructure and the mechanical properties of RS-SiC and RS-$SiC_f/SiC$ materials have been investigated in conjunction with the content of residual silicon and porosity. The mechanical properties of RS-SiC materials suffered from the thermal exposure were also examined. RS-SiC based materials bave been fabricated using the complex matrix slurry with different composition ratios of SiC and C panicles. The characterization of RS-SiC based materials was investigated by means of SEM, EDS ~d three point bending test. Based on the mechanical property-microstructure correlation, the high temperature applicability of RS-SiC based materials was discussed.

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