• Title/Summary/Keyword: C/SiC Composite

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Comparative Study on Performances of Composite Anodes of SiO, Si and Graphite for Lithium Rechargeable Batteries

  • Doh, Chil-Hoon;Veluchamy, Angathevar;Lee, Duck-Jun;Lee, Jung-Hoon;Jin, Bong-Soo;Moon, Seong-In;Park, Cheol-Wan;Kim, Dong-Won
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1257-1261
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    • 2010
  • The electrochemical performances of anode composites comprising elemental silicon (Si), silicon monoxide (SiO), and graphite (C) were investigated. The composite devoid of elemental silicon (SiO:C = 1:1) and its carbon coated composite showed reduced capacity degradation with measured values of 606 and 584 mAh/g at the fiftieth cycle. The capacity retention nature when the composites were cycled followed the order of Si:SiO:C = 3:1:4 < Si:SiO:C = 2:2:4 < SiO:C = 1:1 < SiO:C = 1:1 (carbon coated). A comparison of the capacity retention properties for the composites in terms of the silicon content showed that a reduced silicon content increased the stability of the composite electrodes. Even though the carbon-coated composite delivered low capacity during cycling compared to the other composites, its low capacity degradation made the anode a better choice for lithium ion batteries.

Effect of SiC Nanorods on Mechanical and Thermal Properties of SiC Composites Fabricated by Chemical Vapor Infiltration

  • Lee, Ho Wook;Kim, Daejong;Lee, Hyeon-Geun;Kim, Weon-Ju;Yoon, Soon Gil;Park, Ji Yeon
    • Journal of the Korean Ceramic Society
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    • v.56 no.5
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    • pp.453-460
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    • 2019
  • To reduce residual pores of composites and obtain a dense matrix, SiCf/SiC composites were fabricated by chemical vapor deposition (CVI) using SiC nanorods. SiC nanorods were uniformly grown in the thickness direction of the composite preform when the reaction pressure was maintained at 50 torr or 100 torr at 1,100℃. When SiC nanorods were grown, the densities of the composites were 2.57 ~ 2.65 g/㎤, higher than that of the composite density of 2.47 g/㎤ for non-growing of SiC nanorods under the same conditions; grown nanorods had uniform microstructure with reduced large pores between bundles. The flexural strength, fracture toughness and thermal conductivity (room temperature) of the SiC nanorod grown composites were 412 ~ 432 MPa, 13.79 ~ 14.94 MPa·m1/2 and 11.51 ~11.89 W/m·K, which were increases of 30%, 25%, and 25% compared to the untreated composite, respectively.

A Review of SiCf/SiC Composite to Improve Accident-Tolerance of Light Water Nuclear Reactors (원자력 사고 안전성 향상을 위한 SiCf/SiC 복합소재 개발 동향)

  • Kim, Daejong;Lee, Jisu;Chun, Young Bum;Lee, Hyeon-Geun;Park, Ji Yeon;Kim, Weon-Ju
    • Composites Research
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    • v.35 no.3
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    • pp.161-174
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    • 2022
  • SiC fiber-reinforced SiC matrix composite is a promising accident-tolerant fuel cladding material to improve the safety of light water nuclear reactors. Compared to the current zirconium alloy fuel cladding as well as metallic accident-tolerant fuel cladding, SiC composite fuel cladding has exceptional accident-tolerance such as excellent structural integrity and extremely low corrosion rate during severe accident of light water nuclear reactors, which reduces reactor core temperature and delays core degradation processes. In this paper, we introduce the concept, technical issues, and properties of SiC composite accident-tolerant fuel cladding during operation and accident scenarios of light water nuclear reactors.

Effects of Cu and Mg on Wear Properties of SiC Particulate Reinforced Al-Si Metal Matrix Composites (SiC 입자강화 Al-Si 복합재료의 내마멸성에 미치는 Cu , Mg의 영향)

  • Shim, Shang-Han;Chung, Yong-Keun;Park, In-Min
    • Journal of Korea Foundry Society
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    • v.10 no.1
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    • pp.43-49
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    • 1990
  • The influences of Cu and Mg addition on wear properties of SiC particulate reinforced Al-Si metal(alloy) matrix composites were investigated. Metal matrix composites were prepared by combination of compocasting and hot pressing techniques. The main results obtained are as follows : 1) The composite with Mg addition exhibits letter wear resistance than that with Cu addition. It is considered that Mg addition improved wettability of matal matrix composite by the strong segregation to the SiC / Al matrix interface. 2) After homogenization treatment, it was found that the interfacial segregation of Mg was predominant, while that of Cu was not detected. 3) The SiC / Al-11Si eutectic composite exhibits better wear resistance than the SiC / Al-6Si hypoeutectic composite does. 4) It seems that the increase in the amount of Mg addition affects on the uniform dispersion of SiC particulates, on the refinement of microstructure and on age hardening and these effects cause wear resistance improvement of composites.

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Thickness Dependence of CVD-SiC-Based Composite Ceramic for the Mold of the Curved Cover Glass (곡면 커버 글라스용 금형 코팅을 위한 CVD-SiC 기반 세라믹 복합체의 두께에 따른 특성 연구)

  • Kim, Kyoung-Ho;Jeong, Seong-Min;Lee, Myung-Hyun;Bae, Si-Young
    • Journal of the Korean institute of surface engineering
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    • v.52 no.6
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    • pp.310-315
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    • 2019
  • The use of a silicon carbide (SiC)-based composite ceramic layer for the mold of a curved cover glass was demonstrated. The stress of SiC/VDR/graphite-based mold structure was evaluated via finite element analysis. The results revealed that the maximum tensile stress primarly occured at the edge region. Moreover, the stress can be reduced by employing a relatively thick SiC coating layer and, therefore, layers of various thicknesses were deposited by means of chemical vapor deposition. During growth of the layer, the orientation of the facets comprising the SiC grain became dominant with additional intense SiC(220) and SiC(004). However, the roughness of the SiC layer increased with increasing thickness of the layer and. Hence, the thickness of the SiC layer needs to be adjusted by values lower than the tolerance band of the curved cover glass mold.

Mechanical and Electrical Properties of Hot-Pressed Silicon Carbide-Zirconium Diboride Composites (고온가압소결한 SiC-ZrB$_2$ 복합체의 기계적, 전기적 특성)

  • 신용덕
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.135-140
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    • 1997
  • The influences of ZrB$_2$ additions to SiC on microstructural, DDM(Electrical Discharge Machining), mechanical and electrical properties were investigated. composites were prepared by adding 15, 30, 45 vol.% ZrB$_2$particles as a second phase to SiC matrix. SiC-ZrB$_2$ composites obtained by hot pressing for high temperature structural application were fully dense with the relative densities over 99%. The fracture toughness of the composites were increased with the ZrB$_2$contents. In case of composite containing 30vol.% ZrB$_2$, the flexural strength and fracture toughness showed 45% and 60% increase, respectively compared to that of monolithic SiC sample. The electrical resistivities of SiC-ZrB$_2$ composites decreased significantly with the ZrB$_2$ contents. The electrical resistivity of SiC-30vol.% ZrB$_2$ composite showed 6.50$\times$10$^{-4}$ $\Omega$.cm. Cutting velocity of EDM of SiC-ZrB$_2$ composites are directly proportional to duty factor of pulse width. Surface roughness, however, are not all proportional to pulse width. Higher-flexural strength composites show a trend toward smaller crater volumes, leaving a smoother surface; the average surface roughness of the SiC-ZrB$_2$ 15 vol.% composite with the flexural strengthe of 375㎫ was 3.2${\mu}{\textrm}{m}$, whereas the SiC-ZrB$_2$ 30.vol% composite of 457㎫ was 1.35${\mu}{\textrm}{m}$. In the SEM micrographs of the fracture surface of SiC-ZrB$_2$ composites, the SiC-ZrB$_2$ two phases are distinct; the white phase is the ZrB$_2$and the gray phase is the SiC matrix. In the SEM micrographs of the EDM surface, however, these phases are no longer distinct because of thicker recast layer of resolidified-melt-formation droplets present. It is shown that SiC-ZrB$_2$ composites are able to be machined without surface cracking.

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Enhanced Oxidation Resistance of LSI-Cf/SiC Composite by De-siliconization (탈규소화를 통한 LSI-Cf/SiC 복합재료의 내산화성 향상)

  • Jung Hwan Song;Jung Hoon Kong;Seung Yong Lee;Young Il Son;Do Kyung Kim
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.6
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    • pp.21-27
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    • 2022
  • Cf/SiC composites have low density, high mechanical strength, and good thermal stability, making them promising materials for high-temperature applications such as rocket propulsion and military fields. However, the remaining Si deteriorates physical and thermal properties. In this paper, the de-siliconization was introduced as a method to remove the Si of the Cf/SiC composite fabricated through Liquid Silicon Infiltration(LSI) process. The stability of composite has been tested under an oxyacetylene torch flame for up to 5 minutes. The oxidized surface and cross section of specimens were characterized by 3D scanning, X-ray diffraction(XRD), Optical microscope(OM) and Scanning electron microscope(SEM).

Preparation of Al-SiCp Composite Coating by Plasma Thermal Spray (플라즈마 용사에 의한 Al-SiCp 복합재료 코팅층의 제조)

  • 민준원;유승을;김영정;김정석;서동수
    • Journal of the Korean Ceramic Society
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    • v.40 no.5
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    • pp.460-467
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    • 2003
  • Al-SiC$_{p}$ composite layer was prepared by plasma thermal spray on aluminum substrate using composite powder prepared by mechanical alloying. Mechanically alloyed powder was achieved after 24 h milling, which was used for thermal spray coating. The correlations between process conditions and thickness/porosity were analyzed, and increase of hardness was confirmed. The presence of Al-Si-C-O compound was detected by TEM analysis.

Effects of the Electroplating Duration on the Mechanical Property of the Ni-Co-SiC Composite Coatings

  • Kim, Sung-Min;Lee, Hong-Kee
    • Journal of the Korean institute of surface engineering
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    • v.43 no.6
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    • pp.255-259
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    • 2010
  • In this work, Ni-Co composites incorporated with nano-sized SiC particles in the range of 45-55 nm are prepared by electroplating. The effects of plating duration on the chemical composition, surface morphology, crystalline structures and hardness have been studied. The maximum hardness of Ni-Co-SiC composite coating is approximately 633 Hv at plating duration of 1 h. The hardness is gradually decreased with increasing plating duration, which can be attributed to the growth of crystalline size and the agglomerates of SiC nano-particles. It is therefore explained that the grain refinement of Ni-Co matrix and stable dispersion of SiC particles play an important role for strengthening, which indicate Hall-Petch relation and Orowan model were dominant for hardening of Ni-Co-SiC composite coatings.

Synthesis and Properties of $Al_2O_3-SiC$ Composites from Alkoxides (알콕사이드로부터 $Al_2O_3-SiC$ 복합재료의 제조 및 특성)

  • 이홍림;김규영
    • Journal of the Korean Ceramic Society
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    • v.30 no.2
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    • pp.123-130
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    • 1993
  • Dispersed type Al2O3-SiC composite powders were synthesized from Al-isopropoxide (Al(i-OC3H7)3) and Si(OC2H5)4 precursors by hydrolysis of mixed alkoxides and carbothermal reaction method. The characteristics of the synthesized (dispersed type) Al2O3-SiC composite powders were investigated using XRD, SEM, TEM, BET and particle size analyzer. Carbothermal reaction to produce Al2O3-SiC composite was completed in 10h at 135$0^{\circ}C$ on 3~4㎤/s (0.21~0.28cm/s) of H2 flow rate and about 1/1 of carbon/oxides(=SiO2+Al2O3) molar ratio. The synthesized powders were observed to have the mean particle size range of 0.4~1.26${\mu}{\textrm}{m}$ and showed finer particle size with increasing SiC content.

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