• Title/Summary/Keyword: C/SiC Composite

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Effect of Cold Cyclic Compaction on Densification of $Al_2O_3$ Powder/SiC Whisker Composite ($Al_2O_3$분말과 SiC 휘스커 복합체의 치밀화에 미치는 상온 반복 압축의 영향)

  • 최승완;김기태
    • Journal of the Korean Ceramic Society
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    • v.34 no.3
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    • pp.296-302
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    • 1997
  • The effect of cold cyclic compaction on densification of SiC whisker/Al2O3 composite was investigated. Re-lative density of the compact increased as the number of cycle and the compaction pressure increased and the bias pressure decreased. The rate of loading and unloading and the frequency of cold cyclic compaction did not affect much on sliding and rearrangement of the particles. Fracture of SiC whisker was hardly ob-served during cold cyclic compaction and the direction of whisker was randomly oriented throughout the compact regardless of the direction of compaction. Thus, cold cyclic compaction may be an efficient method to densify SiC whisker/Al2O3 composite.

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Effects of SiC Coating of Carbon Fiber on Mechanical Properties in Short Carbon Fiber Reinforced Al Matrix Composite

  • Jin Man Jang;Se-Hyun Ko;Wonsik Lee
    • Archives of Metallurgy and Materials
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    • v.66 no.4
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    • pp.941-946
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    • 2021
  • A356 Al composites reinforced by short carbon fiber were prepared through the 2-step process: fabrication of a composite precursor and ultrasonication of the precursor melt. The short carbon fibers were coated with 0.15~1.5 ㎛ thick SiC layer by a carbothermal reaction, and an amount of the carbon fiber reinforcement was determined to be 1.5 vol.% and 4.0 vol.%, respectively. The addition of the carbon fiber increased the hardness of A356 alloy. However, tensile strength did not increase in the as-cast composites regardless of the SiC coating and volume fraction of the carbon fiber, due to the debonding which reduced load transfer efficiency from matrix to fiber at the interface. After T6-treatment of the composites, a significant increase in strength occurred only in the composite reinforced by the SiC-coated short carbon fiber, which was considered to result from the formation of a precipitate improving the Al/SiC interfacial strength.

Electrically Conductive Silicon Carbide without Oxide Sintering Additives

  • Frajkorova, Frantiska;Lences, Zoltan;Sajgalik, Pavol
    • Journal of the Korean Ceramic Society
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    • v.49 no.4
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    • pp.342-346
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    • 2012
  • This work deals with the preparation of dense SiC based ceramics with high electrical conductivity without oxide sintering additives. SiC samples with different content of conductive Ti-NbC phase were hot pressed at $1850^{\circ}C$ for 1 h in Ar atmosphere under mechanical pressure of 30 MPa. The conductive phase is a mixture of Ti-NbC in weight ratio of Ti/NbC 1:4. Composite with 50% of conductive Ti-NbC phase showed the highest electrical conductivity of $30.6{\times}10^3\;S{\cdot}m^{-1}$, while the good mechanical properties of SiC matrix were preserved (fracture toughness 4.5 $MPa{\cdot}m^{1/2}$ and Vickers hardness 18.7 GPa). The obtained results show that use of NbC and Ti as sintering and also electrically conductive additives is appropriate for the preparation of SiC-based composite with sufficient electrical conductivity for electric discharge machining.

Impact Resistance of Al2O3-SiC Composites Against High Velocity Copper Jet (고속 구리제트에 대한 알루미나-탄화규소 복합재료의 충돌 저항물성)

  • Kim, Chang-Wook;Lee, Hyung-Bock
    • Journal of the Korean Ceramic Society
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    • v.43 no.10 s.293
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    • pp.660-665
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    • 2006
  • The mechanical properties of $Al_2O_3$-SiC composites manufactured with adding various amount and size of SiC particles have been measured and analyzed. Generally, the elastic modulus of the composites shows about 50% less than that of PL-8 (45 wt% $Al_2O_3$-51 wt% $SiO_2$-4 wt% other oxides), but the flexural strength is similar with each other. The impact resistance property of $Al_2O_3$-SiC composite against high velocity copper jet was lower than that of PL-8 when SiC particles of approximately 3 $\mu$m diameter was added to. It is caused probably due to the micro-pores made by oxidation of SiC particles. However, in the case of the less-weighted $Al_2O_3$-SiC composite adding to 10 wt% SiC with average diameter of 10 $\mu$m and sintering at 1200$^{\circ}C$, the impact resistance property was improved up to 37 percent compared with that of PL-8.

Fabrication of in-situ Formed Namo-Composite Using Polymer Precursor : I. Adsorption Behavior of Polymer Followed $SiO_2$ Surface formation onto Silicon Nitride Surface (폴리머 Precursor를 이용한 in-situ 나노 복합체의 제조 : I. 질화규소 표면에서의 $SiO_2$ 피막형성에 따른 폴리머의 흡착거동)

  • 정연길;백운규
    • Journal of the Korean Ceramic Society
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    • v.37 no.3
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    • pp.280-287
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    • 2000
  • Adsorption behavior and amount of phenolic resin followed silica (SiO2) formation onto silicon nitride(Si3N4) surface were investigated using electrokinetic sonic amplitude (ESA) technique and with UV spectrometer, to fabricate Si3N4/SiC nano-composite based on reaction between SiO2 formed and phenolic resin absorbed onto Si3N4 particle. The amount of SiO2 formed and carbon from phenolic resin absorbed onto Si3N4 surface were calculated quantitatively to adjust the reaction between SiO2 and phenolic resin, resulting in no residual SiO2 and carbon. As a result, pre-heated tempeature for optimized reaction was below 25$0^{\circ}C$, in which there was no residual SiO2 and carbon.

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A Study on Dissolution Behaviors of SiCp in Al-SiCp Composite (Al-SiCp복합재료에서 SiCp의 용해거동에 관한 연구)

  • Kim, Sug-Won;Lee, Eui-Kweon;Jeon, Woo-Yeoung
    • Journal of Korea Foundry Society
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    • v.13 no.4
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    • pp.350-358
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    • 1993
  • Aluminum base composites reinforced with various amount of SiC particles and Mg contents have been investigated by different fabrication method for twenty-years. In this paper, how the decomposition and dissolution behaviors of $SiCp(20{\mu}m)$ in the melt of Al composites arised was studied. As the results, the decomposition and dissolution of SiCp into the melt of Al composites increased with increase of the temperature above $720^{\circ}C$, and holding time at a given melting temperature. Because SiC is thermodynamically unstable in this Al-SiCp composite at temperature above the liquidus, SiCp dissolves and reacts with Al in matrix to form $Al_4C_3$ according to following chemical equation $4Al+3SiC{\rightarrow}Al_4C_3+3Si$, Si decomposed and dissolved from SiCp increases Si content of matrix, while liquidus temperature of matrix decrease with increase of SiC content in matrix. The hardness of SiCp decreased with increase of the melting temperature, the hardness of the matrix /particle interface increased with increase of the melting temperature due to increase of the $Mg_2Si$ and $Al_4C_3$ intermetallic compounds, etc.

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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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Effect of TaB2 Addition on the Oxidation Behaviors of ZrB2-SiC Based Ultra-High Temperature Ceramics

  • Lee, Seung-Jun;Kim, Do-Kyung
    • Korean Journal of Materials Research
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    • v.20 no.4
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    • pp.217-222
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    • 2010
  • Zirconium diboride (ZrB2) and mixed diboride of (Zr0.7Ta0.3)B2 containing 30 vol.% silicon carbide (SiC) composites were prepared by hot-pressing at $1800^{\circ}C$. XRD analysis identified the high crystalline metal diboride-SiC composites at $1800^{\circ}C$. The TaB2 addition to ZrB2-SiC showed a slight peak shift to a higher angle of 2-theta of ZrB2, which confirmed the presence of a homogeneous solid solution. Elastic modulus, hardness and fracture toughness were slightly increased by addition of TaB2. A volatility diagram was calculated to understand the oxidation behavior. Oxidation behavior was investigated at $1500^{\circ}C$ under ambient and low oxygen partial pressure (pO2~10-8 Pa). In an ambient environment, the TaB2 addition to the ZrB2-SiC improved the oxidation resistance over entire range of evaluated temperatures by formation of a less porous oxide layer beneath the surface SiO2. Exposure of metal boride-SiC at low pO2 resulted in active oxidation of SiC due to the high vapor pressure of SiO (g), and, as a result, it produced a porous surface layer. The depth variations of the oxidized layer were measured by SEM. In the ZrB2-SiC composite, the thickness of the reaction layer linearly increased as a function of time and showed active oxidation kinetics. The TaB2 addition to the ZrB2-SiC composite showed improved oxidation resistance with slight deviation from the linearity in depth variation.

The Effect of the Ratio of C45 Carbon to Graphene on the Si/C Composite Materials Used as Anode for Lithium-ion Batteries

  • Hoang Anh Nguyen;Thi Nam Pham;Le Thanh Nguyen Huynh;Tran Ha Trang Nguyen;Viet Hai Le;Nguyen Thai Hoang;Thi Thom Nguyen;Thi Thu Trang Nguyen;Dai Lam Tran;Thi Mai Thanh Dinh
    • Journal of Electrochemical Science and Technology
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    • v.15 no.2
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    • pp.291-298
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    • 2024
  • Due to its high theoretical capacity, Silicon (Si) has shown great potential as an anode material for lithium-ion batteries (LIBs). However, the large volume change of Si during cycling leads to poor cycling stability and low Coulombic efficiency. In this study, we synthesized Si/Carbon C45:Graphene composites using a ball-milling method with a fixed Si content (20%) and investigated the influence of the C45/Gr ratio on the electrochemical performance of the composites. The results showed that carbon C45 networks can provide good conductivity, but tend to break at Si locations, resulting in poor conductivity. However, the addition of graphene helps to reconnect the broken C45 networks, improving the conductivity of the composite. Moreover, the C45 can also act as a protective coating around Si particles, reducing the volume expansion of Si during charging/discharging cycles. The Si/C45:Gr (70:10 wt%) composite exhibits improved electrochemical performance with high capacity (~1660 mAh g-1 at 0.1 C) and cycling stability (~1370 mAh g-1 after 100 cycles). This work highlights the effective role of carbon C45 and graphene in Si/C composites for enhancing the performance of Si-based anode materials for LIBs.

Wear and Friction Characteristics of SiC Reinforced Aluminium 6061 Alloy Composites (SiC 보강 A16061 복합재료의 마멸 및 마찰특성에 관한 연구)

  • 권재도;안정주
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.9
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    • pp.2122-2132
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    • 1995
  • There are some cases which require to grasp the abrasion resistance property in the fields of the high-technology to be required the high specific strength and modulus. In this study, wear test with the various test temperature and velocity were performed in the SiCw/A16061 composite and A16061 matrix using the wear test machine of the ring-on-disc type. As the results, the friction and wear properties by various test temperature and velocity were examined. The worn surface has observed by scanning electron microscope in order to examine the wear mechanism.