• 제목/요약/키워드: magnetic composites

검색결과 186건 처리시간 0.032초

반용융 단조를 위한 복합재료의 수직형 고주파 유도가열 (Induction Heating of Vertical Type for Semi-Solid Forging with Metal Matrix Composites)

  • 이동건;허재찬;강충길
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.385-388
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    • 2001
  • In part forming process of metal matrix composites, the die casting and squeeze casting process are limited the size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting squeeze casting and compocasting. However, for the thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

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Novel Smart Polymeric Composites for Thermistors and Electromagnetic Wave Shielding Effectiveness from TiC Loaded Styrene-Butadiene Rubber

  • Sung, Yong-Kiel;Farid EI-Tantawy
    • Macromolecular Research
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    • 제10권6호
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    • pp.345-358
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    • 2002
  • The electrical conductivity during vulcanization process was measured as a function of time for the system of TiC loaded styrene-butadiene rubber (SBR) composites. The phenomenon of negative and positive temperature coefficients of conductivity and its conduction mechanism were also studied for the SBR polymeric composites. The current-voltage characteristics of the polymeric composites were non-linear in high voltage and showed a switching effect. The effects of temperature on the thermal conductivity and effective dielectric constant were measured. The measured parameters were found to be dependent on TiC concentration. The electromagnetic wave shielding (EMS) of the SBR-TiC polymeric composite was also examined. The SBR filled with TiC could be expected to be promising novel smart polymeric composites for self-electrical heating, temperature sensor, time delay switching, and electro-magnetic wave shielding effectiveness.

(1-x) [0.5PZT-0.25PNN-0.25PZN]- x [Ni0.9Zn0.1Fe2O4] 세라믹스의 압전/자성 성질 및 자기전기적 효과 (Piezoelectric/magnetic Properties and Magnetoelectric Effects in (1-x) [0.5PZT-0.25PNN-0.25PZN] - x [Ni0.9Zn0.1Fe2O4] Particulate Ceramic Composites)

  • 박영권;손세모;류지구;정수태
    • 한국전기전자재료학회논문지
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    • 제23권11호
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    • pp.869-874
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    • 2010
  • Magnetoelectric composites with compositions (1-x)[0.5PZT-0.25PNN-0.25PZN](ferroelectric) - x[$(Ni_{0.9}Zn_{0.1})Fe_2O_4$](ferrite) in which x varies as 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared by conventional ceramic process. The presence of two phases (ferroelectric phase with large grain and ferrite phase with small grain) in the particulate ceramic composites was confirmed by XRD, SEM and EDX. The ferroelectric and magnetic properties of the composites were studied by measuring the P-E and M-H hysterisis loop on the composite composition (x=0, 0.1, 0.2, 1), they were strongly affects of the phase content in composite. The magnetoelectric votage was measured as a function of DC magnetic field and the maximum magnetoelectric voltage coefficient of 14 mV/cm Oe was observed in x=0.2(80 mol% ferroelectric and 20 mol% ferrite phase).

탄소섬유강화 복합재료의 전자파 차폐특성 (Electromagnetic Interference Shielding of Carbon Fibers-Reinforced Composites)

  • 심환보;서민강;박수진
    • 폴리머
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    • 제24권6호
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    • pp.860-868
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    • 2000
  • 본 연구에서는 섬유등급, 배향각 및 적층방법을 달리하여 제조한 탄소섬유강화 복합재료의 제조변수에 따른 전자파 차폐 특성에 관하여 고찰하였다. 그 결과, 탄소섬유강화 복합재료의 전자파 차폐효과는 섬유의 배향각도에 크게 좌우되었다. 특히 0$^{\circ}$의 배향각에서는 섬유의 등급에 따른 영향을 나타내었으며, 동일한 탄소섬유라 할지라도 배열방향에 따른 전기적 성질의 변화, 즉 전기적 이방성이 클수록 차폐효과는 커졌다. 각각의 적층방법에 따라 제조된 모든 시편은 83~98%의 차폐효과를 나타내었으나, 대칭구조와 비대칭구조에서는 적층각도가 커짐에 따라 차폐효과가 소폭 감소하였다. 그러나 반복구조에서는 위의 두 가지 구조와는 다른 경향을 나타내었으며, 특히 90$^{\circ}$ 반복구조의 경우 측정 주파수 전 영역에 걸쳐 90% 이상의 차폐력을 나타내었다.

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