• Title/Summary/Keyword: (B·Si)C composite

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Thermal Sprayed AlSiMg/TiC Composite Coatings : Fabrication of Powder and Characteristics of Coatings (I) (AlSiMg/TiC 복합 용사 피막 : 분말제조 및 피막 특성(I))

  • 양병모;변응선;박경채
    • Journal of Welding and Joining
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    • v.18 no.5
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    • pp.98-104
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    • 2000
  • Aluminum alloys are being employed in automobile parts as strive to reduce overall vehicle weight to meet demands for improved fuel economy and reduction in vehicle emissions. Al-based composites reinforced with ceramic ($Al_2O_3,\;SiC,\;TiC\;and\;B_4C$) applications in a variety of components in automotive engines, such as liners, where the tribological properties of the material are important. In this study, Al-base composites reinforced with TiC particle powders has been developed for producing plasma spray coatings. The composite plasma spray powders were prepared Al-13Si-3Mg(wt%) alloy with TiC(40, 60 and 80wt%) particles ($0.2~5{\mu}textrm{m}$) by drum type ball milling. The composite powders ($36~76{\mu}textrm{m}$) were sprayed with plasma torch. Plasma sprayed coatings were heat-treated at $500^{\circ}C$ for 3 hours. The wear resistances of the plasma sprayed coatings were found to decrease with increasing TiC content and improved with heat treatment. AlSiMg-40% TiC heat-treated coatings were showed the best wear resistance in this study.

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Preparation of Composite Polycrystals Including ${\gamma}$-$6Bi_2O_3$.$SiO_2$ (${\gamma}$-$6Bi_2O_3$.$SiO_2$ 결정을 포함하는 복합다결정체의 작성)

  • 김호건
    • Journal of the Korean Ceramic Society
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    • v.23 no.2
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    • pp.13-20
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    • 1986
  • Composite polycrystals including ${\gamma}$-$6Bi_2O_3$.$SiO_2$ crystal which have needlelike regular structure are useful for the high resolution optical devices. For the purpose of obtaining the composite polycrystals described above the melts of eutectic composition in the three eutectic systems including $6Bi_2O_3$.$SiO_2$ composition were unidirectionally solidified at a rate of 0.05 and 0.25 cm/h under a thermal gradient of 10$0^{\circ}C$/m. Composite polycrystals of relatively regular structure in which needlelike ${\gamma}$-$6Bi_2O_3$.$SiO_2$ crystals were arrayed in parallel with $2Bi_2O_3$.$B_2O_3$ crystal matrix were obtained when the eutectic melt of $6Bi_2O_3$.$SiO_2 -2Bi_2O_3$.$B_2O_3$ system was solidified at a rate of 0.25 cm/h. Partial structural irregularity however was found in the obtained composite polycrystals.

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Gas Pressure Sintering of SiC(p)-TiC(p) Composites (분위기 가압소결에 의한 SiC$_{(P)}$-TiC$_{(P)}$ 복합체 제조)

  • 김인술;김병수;장윤식;박홍채;오기동
    • Journal of the Korean Ceramic Society
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    • v.29 no.10
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    • pp.791-796
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    • 1992
  • SiC(p)-TiC(p) composites were prepared by gas pressure sintering technique. B4C powder and phenolic resin were added as sintering aids by 0.3 wt%-B and 3 wt%-C, TiC powder were dispersed in SiC by 0, 10, 20, 30 and 50 vol%. Flextural strength, fracture toughness and theoretical density of 70 vol% SiC-30 vol% TiC composite sintered at 220$0^{\circ}C$ by gas pressing were 540 MPa, 5.5 MPa.m1/2 and 98.8% respectively.

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Properties of the $\beta$-SiC-$ZrB_2$ Composites with $Al_{2}O_{3}+Y_{2}O_{3}$ additives ($Al_{2}O_{3}+Y_{2}O_{3}$를 첨가한 $\beta$-SiC-$ZrB_2$ 복합체의 특성)

  • Shin, Yong-Deok;Ju, Jin-Young
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.853-855
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    • 1998
  • The electrical resistivity and mechanical properties of the hot-pressed and annealed ${\beta}$-SiC+39vol.%$ZrB_2$ electroconductive ceramic composites were investigated as a function of the liquid forming additives of $Al_{2}O_{3}+Y_{2}O_{3}$(6:4wt%). In this microstructures. no reactions were observed between $\beta$-SiC and $ZrB_2$, and the relative density is over 97.6% of the theoretical density. Phase analysis of composites by XRD revealed mostly of a $\alpha$-SiC(6H, 4H), $ZrB_2$ and weakly $\beta$-SiC(15R) phase. The fracture toughness decreased with increased $Al_{2}O_{3}+Y_{2}O_{3}$ contents and showed the highest for composite added with 4wt% $Al_{2}O_{3}+Y_{2}O_{3}$ additives. The electrical resistivity increased with increased $Al_{2}O_{3}+Y_{2}O_{3}$ contents because of the increasing tendency of pore formation according to amount of liquid forming additives $Al_{2}O_{3}+Y_{2}O_{3}$. The electrical resistivity of composites is all positive temperature coefficient resistance(PTCR) against temperature up to $700^{\circ}C$.

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Improvement of Impact Resistance of B4C Tile Inserted B4Cp/Al7075 Hybrid Composites Through Interface Control (B4C tile 삽입 B4Cp/Al7075 하이브리드 복합재의 계면 제어를 통한 내충격 특성의 향상)

  • Park, Jongbok;Lee, Taegyu;Lee, Donghyun;Cho, Seungchan;Lee, Sang-Kwan;Hong, Soon Hyung;Ryu, Ho Jin
    • Composites Research
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    • v.33 no.5
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    • pp.235-240
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    • 2020
  • In this study, in order to improve the impact resistance of the B4C tile-inserted B4Cp/Al7075 hybrid composite, a control method of the B4C/Al7075 interface was developed and the characteristics of the controlled interface were analyzed. B2O3, Ni, and Si were coated on the B4C tile surface using additional thermal oxidation, electroless plating, and plasma spraying. The coated B4C tile is inserted into the B4Cp/Al7075 composite material using the liquid pressurization method. Interfacial energy, bonding strength, and impact resistance were measured to analyze the effect of the coating. All coatings enhanced interfacial energy, bonding strength, and impact resistance, and in particular, it was confirmed that the impact resistance increased by 86.8% when B2O3 coating was used. This study is significant in developing and analyzing a core surface treatment method that improves the performance of B4C/Al series composites, which are attracting attention as next-generation lightweight amour and bulletproof materials.

Sintering Characterization of Hot-Pressed SiC Prepared by SHS Microwave Method (SHS Microwave 법으로 합성한 SiC 분말의 고온가압 소결특성)

  • 김도경;안주삼;김익진;이형복
    • Journal of the Korean Ceramic Society
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    • v.32 no.8
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    • pp.865-872
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    • 1995
  • Ultra-fine $\beta$-SiC powders were fabricated by self-propagating high temperature synthesis process (SHS) using microwave oven. The flexural strength, fracture toughness, and hardness of hot pressed sample at 200$0^{\circ}C$ for 60 min using synthesized SiC powders, which had 2 wt% of Al2O3 and 2.5 wt% of B4C content, showed 438 MPa, 4.15MPa.m1/2 and 28 GPa, respectively. The highest strength, fracture toughness, and hardness of composites containing 4wt% of Al2O3, which had highest relative density of 99.9%, showed 458 MPa, 4.6MPa.m1/2 and 36.2 GPa, respectively.

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Fractographic Analysis of Ceramic Composites by Transmission Electron Microscopy using Surface Replication Technique (표면복제법을 이용한 세라믹 복합재료 파괴현상의 투과전자현미경 분석)

  • Jun, Hyeung-Woo;Kim, Gyeung-Ho;Kim, Byung-Ho
    • Applied Microscopy
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    • v.26 no.4
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    • pp.447-456
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    • 1996
  • Fracture surfaces of materials contain useful information ranging from crack path to the mechanism of fracture. Since limitation of electron transparency requires a sample in the form of thin foil for TEM observations, it is impossible to extract such information directly from the fracture surfaces. In this study, the method of surface replication from the ceramic fracture surface is employed to characterize the process of crack propagation in ceramic matrix composites using TEM analysis. The surface replica from the fracture surface in ceramic materials provides detailed surface morphology and more importantly, loosened particles on the fracture surface are collected. Electron diffraction and chemical composition analyses of these particles reveal crack path in the specimen. Furthermore, one can determine the mode of fracture by observing the fracture surface morphology from the image of replica. Two examples are given to illustrate the potential of the surface replication technique. In the first example, apparent toughness increase in $B_{4}C-Al$ composites at high strain rate is investigated by surface replication to elucidate the mechanism of fracture at different strain rates. The polytypes of SiC formed during the sintering of SiC-AlN composite and their effect on the fracture behavior of SiC-AlN composite are analyzed in the second example.

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Si@C/rGO Composite Anode Material for Lithium Ion Batteries (리튬 이온 전지용 음극으로서의 Si@C/rGO의 합성)

  • Chaehyun Kim;Sung Hoon Kim;Wook Ahn
    • Journal of the Korean Electrochemical Society
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    • v.27 no.2
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    • pp.73-79
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    • 2024
  • As the use of fossil fuels has gradually increased, so has the emission of greenhouse gases such as carbon dioxide, leading to environmental problems. As a result, lithium-ion batteries (LiB) have emerged as the solution to this issue. To manufacture medium to large-sized lithium-ion batteries (LiB), it requires electrodes with high capacity and fast charging capabilities. Silicon (Si) is considered a next-generation anode with high-capacity properties, so, reduced graphene oxide (rGO) was compounded with Si@resorcinol-formaldehyde resin (RF) composite to prevent the volume expansion of Si. It was confirmed that the composite anode prepared exhibited improved capacity and enhanced stability.

Manufacture and Properties of $SiC-TiB_2$Electroconductive Ceramic Composites for Pressureless Sintering (상압소결을 위한 $SiC-TiB_2$ 전도성 세라믹 복합체의 제조와 특성)

  • Ju, Jin-Yeong;Sin, Yong-Deok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.10
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    • pp.500-503
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    • 2001
  • The mechanical and electrical properties of the hot-pressed and pressureless annealed SiC+39vol.%$TiB_2$electroconductive ceramic composites were investigated as a function of the liquid additives of $Al_2O_3+Y_2O_3$. The result of phase analysis for the SiC+39vol.%$TiB_2$composites by XRD revealed $\alpha$-SiC(6H), $TiB_2$, and $YAG(Al_5Y_3O_{12})4 crystal phase. The relative density of SiC+39vol.%$TiB_2$ composites was increased with increased $Al_2O_3+Y_2O_3$. contents. The fracture toughness showed the highest value of $7.8 MPa.m^{1/2}$ for composites added with 12 wt % $Al_2O_3+Y_2O_3$. additives at room temperature. The electrical resistivity and the resistance temperature coefficient showed the lowest value of $7.3\times10_{-4}\Omega.cm\; and\; 3.8\times10_{-3}/^{\circ}C$ for composite added with 12 wt% $Al_2O_3+Y_2O_3$. additives at room temperature. The electrical resistivity of the SiC+39vol.%$TiB_2$composites was all positive temperature coefficient resistance(PTCR) in the temperature ranges from $25^{\circ}C\; to\; 700^{\circ}C$.

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A Study on the Relationship between Residual Stress and Wear Peroperty in Hypereutectic Al-Si Alloys (과공정 Al-Si 합금의 마모 특성에 미치는 잔류응력의 영향에 관한 연구)

  • Kim, Heon-Joo;Kim, Chang-Gyu
    • Journal of Korea Foundry Society
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    • v.20 no.2
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    • pp.89-96
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    • 2000
  • The effects of modification processing on the refinement of primary Si and the wear behavior of hyper-eutectic Al-Si alloys have been mainly investigated. Refining effects of primary Si in Al-17%Si alloy was more efficient than that of B.390 alloy. Optimum condition of getting the finest primary Si microstructure was when AlCuP modifier is added into the melt at $750^{\circ}C$ and held it at $700^{\circ}C$ for 30 minutes. Wear loss in the specimens of as-cast condition decreases as the size of primary Si decreases, in the order of B.390 alloy, B.390 alloy with AlCuP addition, Al-17%Si alloy and Al-17%Si alloy with AlCuP addition. Wear loss in the aged condition of Al-17%Si alloy, B.390 alloy and B.390 alloy with AlCuP addition decreased due to the increase of compressive residual stress in the matrix by the aging treatment. While, wear loss increased in the aged specimens of Al-17%Si alloy with AlCuP addition and Hepworth addition in which compressive residual stress decreases by the aging treatment. Therefore, it is assumed that higher compressive residual stress in the matrix can reduce the wear loss in composite materials such as hyper-eutectic Al-Si alloys.

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