• 제목/요약/키워드: NiFe nanoparticles

검색결과 56건 처리시간 0.021초

NiO의 첨가에 따른 α-Fe2O3 나노입자 센서의 에탄올 가스 검출 특성 향상 (Improved Ethanol Gas Sensing Performance of α-Fe2O3 Nanoparticles by the Addition of NiO Nanoparticles)

  • 박성훈;강우승
    • 한국표면공학회지
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    • 제49권1호
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    • pp.69-74
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    • 2016
  • In order to investigate the effect of NiO on the ethanol gas sensing performance of ${\alpha}-Fe_2O_3$ nanoparticles, NiO and ${\alpha}-Fe_2O_3$ nanoparticles are synthesized by hydrothermal method. The sensor with ${\alpha}-Fe_2O_3$ and NiO nanoparticles mixed at an optimum ratio of 7:3 showed 3.8 times improved sensing performance for 200ppm ethanol gas at $200^{\circ}C$. The enhanced gas sensing performance can be considered to be caused by pn heterojunction at the grain boundaries of ${\alpha}-Fe_2O_3$ and NiO nanopartcles.

Fe-Ni 합금 나노 분말의 마르텐사이트 변태에 관한 연구 (A Study on Martensite Transformation of Fe-Ni Alloy Nanoparticles)

  • 유연태
    • 한국재료학회지
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    • 제13권8호
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    • pp.491-496
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    • 2003
  • Fe-Ni alloy nanoparticles were prepared by ERC (Evaporation and Rapid Condensation) method, and the crystal structure and the behavior of martensite for the nanosized alloy particles were investigated by X-ray diffraction analysis. The relation between the rate of martensite transformation and the internal strain of austenite was discussed. The lattice spaces of austenite and martensite for the nanoparticles agreed with those of the bulk materials. The rate of martensite transformation from austenite and the internal strain of austenite was reduced with decreasing the average size of Fe-Ni nanoparticles. It was thought that the residual austenite in the Ni content range of 11∼l5at% was caused by the internal strain, and the residual martensite in the Ni content range of 32∼36at% had its origin in the high surface energy of nanoparticles.

Evaluation of Magnetic and Thermal Properties of Ferrite Nanoparticles for Biomedical Applications

  • Tomitaka, Asahi;Jeun, Min-Hong;Bae, Seong-Tae;Takemura, Yasushi
    • Journal of Magnetics
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    • 제16권2호
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    • pp.164-168
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    • 2011
  • Magnetic nanoparticles can potentially be used in drug delivery systems and for hyperthermia therapy. The applicability of $Fe_3O_4$, $CoFe_2O_4$, $MgFe_2O_4$, and $NiFe_2O_4$ nanoparticles for the same was studied by evaluating their magnetization, thermal efficiency, and biocompatibility. $Fe_3O_4$ and $CoFe_2O_4$ nanoparticles exhibited large magnetization. $Fe_3O_4$ and $NiFe_2O_4$ nanoparticles exhibited large induction heating. $MgFe_2O_4$ nanoparticles exhibited low magnetization compared to the other nanoparticles. $NiFe_2O_4$ nanoparticles were found to be cytotoxic, whereas the other nanoparticles were not cytotoxic. This study indicates that $Fe_3O_4$ nanoparticles could be the most suitable ones for hyperthermia therapy.

마이크로입자의 레이저 Ablation으로 형성된 나노입자의 수펴소닉 적층법을 이용한 퍼멀로이 나노구조박막 적층에 관한 연구 (A Study on the Deposition of Permalloy Nanostructured Thin Film Utilizing Supersonic Deposition of Nanoparticles Formed by Laser Ablation of Microparticles)

  • 윤의중;정명희
    • 한국전기전자재료학회논문지
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    • 제18권5호
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    • pp.478-483
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    • 2005
  • In this paper, we synthesized 10 to 20 nm diameter NiFe nanoparticles and nanoparticle films utilizing supersonic jet deposition of nanoparticle aerosols generated by laser ablation of $30\;to\;45{\mu}m$ diameter permalloy $(Ni_{81}Fe_{19} \;at\;{\%})$ microparticles. The component and composition of the nanoparticles were characterized by an energy dispersive X-ray spectroscopy. The morphology of the nanoparticles and nanoparticle films was analyzed by a high-resolution transmission electron microscopy and a scanning electron microscopy, respectively. The experimental results showed that the nanoparticles and nanoparticle films have remarkable properties with an excellent preservation of the composition of feedstock permalloy microparticles. The purpose of the present work is to present details on the composition and nanostructural characterizations for NiFe nanoparticles and nanoparticle films prepared by laser ablation of microparticles (LAM).

Magnetic Behaviors of Isolated Fe-Co-Ni Nanoparticles in a Random Arrangement

  • Yang, Choong Jin;Kim, Kyung Soo;Wu, Jianmin
    • Journal of Magnetics
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    • 제6권3호
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    • pp.94-100
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    • 2001
  • Fe-Co-Ni particles with an average size of 45 and 135 nm are characterized in terms of magnetic phase transformation and magnetic properties at room temperature. BCC structure of Fe-Co-Ni spherical particles can be synthesized from Fe-Co-Ni-Al-Cu precursor films by heating at 600-80$0^{\circ}C$ for the phase separation of Fe-Co rich Fe-Co-Ni particles, followed by a post heating at $600^{\circ}C$ for 5 hours. The average size of nanoparticles was directly determined by the thickness of precursor films. Exchange interactive hysteresis was observed for the nano-composite (Fe-Co-Ni)+(Fe-Ni-Al) films resulting from the short exchange interface between ferromagnetic Fe-Co-Ni particles surrounded by almost papramagnetic Ni-Al-Fe matrix. Arraying the isolated Fe-Co-Ni nano-particles in a random arrangement on $Al_2O_3$substrate the particle assembly showed a behavior of dipole interactive ferromagnetic clusters depending on their volume and inter-particle distance.

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친핵성 용매 중에서 자발적 환원반응에 의한 음이온 교환막 수전해용 Fe/Ni 나노 촉매의 제조 및 특성 (Preparation and Characterization of Fe/Ni Nanocatalyst in a Nucleophilic Solvent for Anion Exchange Membrane in Alkaline Electrolysis)

  • 대관하;노립신;이재영;이홍기
    • 한국수소및신에너지학회논문집
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    • 제32권5호
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    • pp.293-298
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    • 2021
  • To synthesize Fe/Ni nanocatalysts loaded on carbon black, Iron(II) acetylacetonate and nickel (II) acetylacetonate and were reduced to Fe and Ni metallic nanoparticles by a spontaneous reduction reaction. The distribution of the Fe and Ni nanoparticles was observed by transmission electron microscopy, and the loading weight of Fe/Ni nanocatalysts on the carbon black was measured by thermogravimetric analyzer. The elemental ratio of Fe and Ni was estimated by energy dispersive x-ray analyzer. It was found that the loading weight of Fe/Ni nanoparticles was 6.23 wt%, and the elemental ratio of Fe and Ni was 0.53:0.40. Specific surface area was measured by BET analysis instrument and I-V characteristics were estimated.

액중 전기선 폭발 공정을 이용한 Pt/alloy 하이브리드 나노입자의 제조 및 그 특성 (Synthesis of Pt/alloy Nanoparticles by Electrical Wire Explosion in Liquid Media and its Characteristics)

  • 구혜영;윤중열;양상선;이혜문
    • 한국입자에어로졸학회지
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    • 제8권2호
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    • pp.83-88
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    • 2012
  • The electrical wire explosion process in liquid media is promising for nano-sized metal and/or alloy particles. The hybrid Pt/Fe-Cr-Al and Pt/Ni-Cr-Fe nanoparticles for exhaust emission control system are synthesized by electrical wire explosion process in liquid media. The alloy powders have spherical shape and nanometer size. According to the wire component, while Pt/Fe-Cr-Al nanoparticles are shown the well dispersed Pt on the Fe-Cr-Al core particle, Pt/Ni-Cr-Fe nanoparticles are shown the partially separated Pt on the Ni-Cr-Fe core particle. Morphologies and component of two kinds of hybrid nano catalyst particles were characterized by transmission electron microscope and energy dispersive X-ray spectroscopy analysis.

Superparamagnetic Properties of Nanoparticles Ni0.9Zn0.1Fe2O4 for Biomedical Applications

  • Lee, Seung-Wha;Kim, Chul-Sung
    • Journal of Magnetics
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    • 제10권1호
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    • pp.5-9
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    • 2005
  • Nanoparticles $Ni_{0.9}Zn_{0.1}Fe_2O_4$ is fabricated by a sol-gel method. The magnetic and structural properties of powders were investigated with XRD, SEM, Mossbauer spectroscopy, and VSM. $Ni_{0.9}Zn_{0.1}Fe_2O_4$ powders annealed at $300{^{\circ}C}$ have a spinel structure and behaved superparamagnetically. The estimated size of $Ni_{0.9}Zn_{0.1}Fe_2O_4$ nanoparticle is about 10 nm. The hyperfine fields at 13 K for the A and B patterns are found to be 533 and 507 kOe, respectively. The ZFC curves are rounded at the blocking temperature ($T_B$)and show a paramagnetic-like behavior above $T_B$. $T_B$ of $Ni_{0.9}Zn_{0.1}Fe_2O_4$ nanoparticle is about 250 K. Nanoparticles $Ni_{0.9}Zn_{0.1}Fe_2O_4$ annealed at 400 and $500{^{\circ}C}$ have a typical spinel structure and is ferrimagnetic in nature. The isomer shifts indicate that the iron ions were ferric at the tetrahedral (A) and the octahedral (B). The saturation magnetization of nanoparticles $Ni_{0.9}Zn_{0.1}Fe_2O_4$ annealed at 400 and $500{^{\circ}C}$ are 40 and 43 emu/g, respectively. The magnetic anisotropy constant of $Ni_{0.9}Zn_{0.1}Fe_2O_4$ annealed at $300{^{\circ}C}$ were calculated to be 1.6 ${\times}$ $10^6$ ergs/$cm^3$.

Densification Behavior of Fe-Ni Alloy Nanoparticles

  • Kim, Sang-Phil;Lee, Woo-Seok;Lee, Jae-Wook;Choi, Chul-Jin
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.531-532
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    • 2006
  • The effects of compaction pressure and sintering temperature on the densification of Fe-40wt%Ni alloy nanoparticles were analyzed. The Fe-Ni nanoparticles were fabricated by an arc-discharge method and then, compacted at three different pressures and sintered at 550 to $900\;^{\circ}C$. Densification was completed at temperature as low as $600\;^{\circ}C$ and high-pressure compaction was found to enhance densification. Densification behaviors and microstructure developments have been investigated through density measurements, electron microscopies, and hardness measurements.

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건식 공정에서 자발적 환원 반응에 의한 AEM 수전해용 Fe-Ni 나노 촉매 제조 및 특성 (Preparation and Characterization of Fe-Ni Nanocatalyst for AEM Electrolysis via Spontaneous Reduction Reaction in Dry Process)

  • 이재영;이홍기
    • 한국수소및신에너지학회논문집
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    • 제35권2호
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    • pp.185-194
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    • 2024
  • Fe-Ni nanocatalysts loaded on carbon black were prepared via spontaneous reduction reaction of iron (II) acetylacetonate and nickel (II) acetylacetonate in dry process. Their morphology and elemental analysis were characterized by scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray analyzer. The loading weight of the nanocatalysts was measured by thermogravimetric analyze and the surface area was measured by BET analysis. TEM observation showed that Fe and Ni nanoparticles was well dispersed on the carbon black and their average particle size was 4.82 nm. The loading weight of Fe-Ni nanocatalysts on the carbon black was 6.83-7.32 wt%, and the value increased with increasing iron (II) acetylacetonate content. As the Fe-Ni loading weight increased, the specific surface area decreased significantly by more than 50%, because Fe-Ni nanoparticles block the micropores of carbon black. I-V characteristics showed that water electrolysis performance increased with increasing Ni nanocatalyst content.