• 제목/요약/키워드: SiC powder

검색결과 779건 처리시간 0.031초

고순도 SiC 미분말을 적용한 4H-SiC 단결정 성장에 관한 연구 (Study on the growth of 4H-SiC single crystal with high purity SiC fine powder)

  • 신동근;김병숙;손해록;김무성
    • 한국결정성장학회지
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    • 제29권6호
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    • pp.383-388
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    • 2019
  • 개선된 열탄소환원법으로 합성된 금속불순물함량 1 ppm 이하의 고순도 SiC 미립 분말을 이용하여 2,100℃ 이상고온의 RF 가열 PVT 장치에서 SiC 단결정을 성장시켰으며, In-situ x-ray 이미지 분석을 통해 성장과정 중 분말의 승화거동 및 단결정 성장거동을 관찰하였다. SiC 분말은 단결정 성장의 공급원으로 온도가 높은 외곽 부분부터 소진되고 graphite 잔여물이 남았다. 성장 중 원료의 흐름은 가운데 부분으로 집중되었으며 SiC 단결정의 성장거동에도 영향을 미쳤는데, 이는 미립분말로 인한 도가니 내부 온도분포 차이가 원인으로 예상되었다. 단결정 성장이 완료된 후, 단결정 잉곳을 1 mm 두께의 단결정 기판으로 절단하고 또한, 잉곳에서 얻어진 단결정 기판은 전반적으로 짙은 황색의 4H -SiC가 관찰되었으며, 외곽에 일부 발생한 다결정은 시드결정을 시드홀더에 부착하는 과정에서 혼입된 기포층과 같은 불순물 혼입이 원인으로 사료된다.

Ni-SiC 복합도금층의 내마모성에 관한 연구 (A study on the wear resistance of Ni-SiC composite plating)

  • 김성호;한혜원;장현구
    • 한국표면공학회지
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    • 제29권1호
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    • pp.26-35
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    • 1996
  • The Ni-SiC composite plating was performed in a Watt nickel solution and the wear resistance of the composite layer was studied on a pin-on-flat type wear tester. The volume losses and friction coefficients were measured. It was found that the quantity of SiC powder in the composite layers was affected by SiC concentration, pH, temperature, and agitation speed in the Watt nickel solution. The hardness and wear resistance of the coatings increased with SiC content. The quantity of SiC powder in the coating from a nickel sulfamate solution is larger than that of the Watt nickel solution, because the amount of nickel ions absorbed on the SiC powder in the nickel sulfamate solution is greater than that in the Watt's solution.

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SHS법에 의한 $Al_2O_3-SiC$ 복합분말의 합성 (Preparation of $Al_2O_3-SiC$ Composite Powder by SHS Method)

  • 이형민;이홍림;이형직
    • 한국세라믹학회지
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    • 제32권1호
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    • pp.11-16
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    • 1995
  • High reaction heat evolved from the oxidation of Al was used to synthesize SiC, which might be difficult to be formed by SHS. Al2O3-SiC composite powder was easily manufactured using KNO3 as an ignition and reaction catalyst. Unreacted Si and C were observed after reaction dependent upon the composition of starting powders, reaction atmosphere and relative densities of compacted bodies. The unreacted carbon could be removed by calcining at $600^{\circ}C$ and the remaining Si could be removed by dissolving in NaOH solution. The final powder particles were smaller than 1${\mu}{\textrm}{m}$ in size.

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Phase Equilibria and Reaction Paths in the System Si3N4-SiC-TiCxN1-x-C-N

  • H.J.Seifert
    • 한국분말재료학회지
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    • 제6권1호
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    • pp.18-35
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    • 1999
  • Phase equilibria in the system Si3N4-TiC-TiCxN1-x-C-N were determined by thermodynamic calculations (CALPHAD-method). The reaction peaction paths for Si3N4-TiC and SiC-TiC composites in the Ti-Si-C-n system were simulated at I bar N2-pressure and varying terpreatures. At a temperature of 1923 K two tie-triangles (TiC0.34N0.66+SiC+C and TiC0.13N0.87+SiC+Si3N4) and two 2-phase fieds (TiCxN1-x+SiC; 0.13

분말야금법으로 제조된 FeSi2 열전특성 화합물의 열처리 시간에 따른 미세조직과 상변화 (Phase Transformation and Microstructure of FeSi2 Thermoelectric Compounds Manufactured by Powder Metallurgy)

  • 박경태;신진교;홍순직;천병선
    • 한국분말재료학회지
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    • 제17권6호
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    • pp.482-488
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    • 2010
  • In this study, $FeSi_2$ as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below $1200^{\circ}C$ for 3 h. Due to its high brittleness, the cast alloy transformed to fine powders by ball-milling, followed by subsequent compaction (hydraulic pressure; 2 GPa) and sintering ($1200^{\circ}C$, 12 h). In order to precipitate ${\beta}-FeSi_2$, heat treatment was performed at $850^{\circ}C$ with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase ${\beta}-FeSi_2$ was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.

ZrB2-SiC 복합세라믹스의 미세구조와 열전도도에 미치는 SiC 크기와 첨가량의 영향 (Effect of the Size and Amount of SiC on the Microstructures and Thermal Conductivities of ZrB2-SiC Composite Ceramics)

  • 김성원;권창섭;오윤석;이성민;김형태
    • 한국분말재료학회지
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    • 제19권5호
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    • pp.379-384
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    • 2012
  • This paper reports the microstructures and thermal conductivities of $ZrB_2$-SiC composite ceramics with size and amount of SiC. We fabricated sintered bodies of $ZrB_2$-x vol.% SiC (x=10, 20, 30) with submicron and nanosized SiC densified by spark plasma sintering. Microstructure retained the initial powder size of especially SiC, except the agglomeration of nanosized SiC. For sintered bodies, thermal conductivities were examined. The observed thermal conductivity values are 40~60 W/mK, which is slightly lower than the reported values. The relation between microstructural parameter and thermal conductivity was also discussed.

제천규석으로부터 SiC 및 $SiC-Si_3N_4$계 분말 합성 (Syntheses of SiC and $SiC-Si_3N_4$ Powder from Jecheon Quartz)

  • 이홍림;배철훈;문준화
    • 한국세라믹학회지
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    • 제23권1호
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    • pp.67-73
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    • 1986
  • SiC and $SiC-Si_3N_4$ powder were synthesized via the carbiding and carbiding-nitriding reaction of Jecheon quartz respectively using graphite as a reducing agent. $\beta$-SiC+($\alpha$+$\beta$)-$Si_3N_4$ composite was obtained by the carbiding-nitriding reaction of Jecheon quartz-graphite mixture at 1, 35$0^{\circ}C$ in $H_2$ atmosphere. $\beta$-SiC+($\alpha$+$\beta$)-$Si_3N_4$ composite was obtained by the carbidint-nitriding reaction of Jecheon quartz-graphite mixture at 1, 35$0^{\circ}C$ in $N_2-H_2$ atmosphere. The ratio of $\beta$-SiC+($\alpha$+$\beta$)-$Si_3N_4$ content in a produced composite could be controlled by adjusting the reaction time and gaseous mixture.

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가압소결 $SiC/Si_3N_4$ 복합체의 마찰마모특성 (Tribological Properties of Hot Pressed $SiC/Si_3N_4$ Composites)

  • 백용혁;최웅;박용갑
    • 한국세라믹학회지
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    • 제36권10호
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    • pp.1102-1107
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    • 1999
  • SiC-Si3N4 composites were prepared by mixing $\alpha$-Si3N4 powder to $\alpha$-SiC powder in the range of 10 to 30 vol% with 10vol% interval. 6wg% Al2O3 and 6wt% Y2O3 were respectively added as sintering aids. Hot pressing was performed at 1,80$0^{\circ}C$ for 1 hour with 25 MPa pressure. In the case of adding 20vol% of $\alpha$-Si3N4 powder the relative density to theoretical value and the flexural strength were 99.1% and 34,420 MPa respectively and the worn amount was 2.09$\times$10-3 mm2 which were the highest values in the all range of he composition. Although the composite containig 10 vol% of $\alpha$-Si3N4 powder showed the highest fracture toughness(KIC) of 4.65MN/m3/2 the reduction of the wear resistance in this composite is likely to be affected by the homogeneity and the uniformity of the grain coalescence and growth during the sintering process.

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가스분무 공정에 의한 고강도 과공정 Al-Si 합금 분말의 제조 및 특성 연구 I. 분말 제조 및 성형성 (Fabrication and Properties of High Strength Hypereutectic Al-Si Powder by Gas Atomization Process I. Powder Production and Compressibility)

  • 김용진;김진천
    • 한국분말재료학회지
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    • 제12권4호
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    • pp.296-302
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    • 2005
  • In order to improve mechanical properties, the hypereutectic Al-20 wt%Si based prealloy powder was prepared by gas atomization process. Microstructure and compressibility of the atomized Al-Si powder were investigated. The average powder size was decreased with increasing the atomization gas pressure. Size of primary Si particles of the as-atomized powder was about $5-8\;\mu{m}$. The as-atomized Al-Si powder such as AMB 2712 and AMB 7775 to increase compressibility and sinterability. Relative density of the mixed powder samples sintered at $600^{\circ}C$ was reached about 96% of a theoretical density.