• Title/Summary/Keyword: Ni-Zn-Co ferrites

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Synthesis Processing of the Fine (Ni, Zn)-ferrite Powder for $CO_2$ Decomposition of the Flue Gas in the Iron Foundry (제철소의 연소배가스 $CO_2$ 분해용 (Ni, Zn)-ferrite 미세분말 합성공정 연구)

  • 김정식;안정률
    • Journal of the Korean Ceramic Society
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    • v.37 no.2
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    • pp.164-167
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    • 2000
  • Flue gases in the iron foundry consist of 15~20% CO2 as an air pollution gas whose emission should be mitigated in order to protect the environment. In the present study, ultrafine powders of NixZn1-xFe2O4 as a potential catalyst for the CO2 decomposition were prepared by the coprecipitation methods. Oxygen deficient ferrites (MeFe2O4-$\delta$) can decompose CO2 as C and O2 at a low temperature of about 30$0^{\circ}C$. The XRD result of synthesized ferrites showed the spinel structure of ferrites and ICP-AES and EDS quantitative analyses showed the composition similar with initial molar ratios of the mixed solution prior to reaction. The BET surface area of the (Ni, Zn)-ferrites was about 77~89.5$m^2$/g and their particle size was observed about 10~20 nm. The CO2 decomposition efficiency of the oxygen deficient (Nix, Zn1-x)-ferrites was the highest at x=0.3, and the ternary (Ni, Zn)-ferrites was better than that of binary Ni-ferrites.

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CO2 Decomposition with Waste Ferrite (폐기물 페라이트를 이용한 CO2분해)

  • 신현창;김진웅;최정철;정광덕;최승철
    • Journal of the Korean Ceramic Society
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    • v.40 no.2
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    • pp.146-152
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    • 2003
  • The waste ferrites from magnetic core manufacturing process were used to $CO_2$gas decomposition to avoid the greenhouse effects. The waste ferrites are the mixed powder of Ni-Zn and Mn-Zn ferrites core. In the reduction of ferrites by 5% $H_2/Ar$ mixed gas, the weight loss of ferrites was about 14~16wt%. After the$CO_2$gas decomposition reaction, the weight of the reduced ferrites was increased up to 11wt%.$CO_2$gas was decomposed by oxidation of Fe and FeO in reduced compound and the phase of the waste ferrite was changed to spinel structure. A new technique capable of$CO_2$decomposition as low cost process through utilizing waste ferrite was development.

The Variation of Permeability and$Q_{max}$ Frequency with Processing Parameters in NiCuZn Ferrites (제조 공정 Parameter에 따른 NiCuZn Ferrite의 투자율과 $Q_{max}$ 주파수 변화)

  • 신재영;박지호;박진채;한종수;송병무
    • Journal of the Korean Magnetics Society
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    • v.7 no.1
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    • pp.19-24
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    • 1997
  • Composition and process conditions for low temperature sintered NiCuZn ferrites were investigated, so as to fabricate multilayered chip inductor. The$Fe_2O_3$ deficiency for low temperature sintering was decreased with NiO contents of NiCuZn ferrites. The permeability of NiCuZn ferrites can be controlled in the range of 12~562 with the variation of NiO and $Co_3O_4$ contents. The $Q_{max} $ frequency of NiCuZn ferrites was decreased from 50 MHz to 3 MHz linearly with permeability increase from 60 to 560. The relation between the $Q_{max}$ frequency(Y) and permeability(X) of NiCuZn ferrites was expressed with the following empirical equation, logY=4.2-1.4logX.

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Study on The Synthesis of The Ultra-Fine (Ni, Zn)-ferrite by The Hydrothermal Method and its $CO_2$ Decomposition (수열합성법에 의한(Ni, Zn)-Ferrites의 초미세분말 합성공정 및 $CO_2$분해 특성 연구)

  • Kim, Jeong-Sik;An, Jeong-Ryul;Ryu, Ho-Jin
    • Korean Journal of Materials Research
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    • v.10 no.3
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    • pp.223-226
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    • 2000
  • The oxygen deficient ferrites $(Ni_x,\; Zn_{1-x})Fe_2O_{4-{\delta}}$ can decompose $CO_2$ as C and $O_2$ at a low temperature of about $300^{\circ}C$. Ultra powders of $(Ni_x,\; Zn_{1-x})Fe_2O_4$ for the $CO_2$ decomposition were prepared by the hydrothermal methods. The XRD result of synthesized ferries showed the spinel structure of ferrites and ICP-AES and EDS quantitative analyses showed the composition similar with the starting molar ratios of the mixed solution prior to reaction. The BET surface area of the synthesized(Ni, Zn)-ferrites was above $110\textrm{m}^2/g$ and its particle size was very as small as about 5~10 nm. The $CO_2$ decomposition efficiency of the oxygen deficient ferrites($(Ni_x,\;Zn_{1-x})Fe_2O_{4-{\delta}}$) was almost independent with composition and the $CO_2$ decomposition efficiency of ternary (Ni, Zn)-ferrites was better than of binary Ni-ferrites.

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Improvement of $CO_2$Decomposition by Impregnating Noble Metals to Nano-size (Ni, Zn)-ferrites (귀금속 첨가에 의한 나노 (Ni, Zn)-페라이트의 $CO_2$분해 향상)

  • Kim, Jeong-Sik;An, Jeong-Ryul;Gang, Gye-Myeong
    • Korean Journal of Materials Research
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    • v.11 no.10
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    • pp.846-850
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    • 2001
  • In the present study, nano-size powders of ternary ferrites, $Ni_{0.5}Zn_{0.5}Fe_2O_4$, as the potential catalysts of $CO_2$decomposition, were prepared by the wet processing of hydrothermal synthesis and coprecipitation method, and the catalyzing effects of impregnation of the noble metals, Pt and Pd, onto $Ni_{0.5}Zn_{0.5}Fe_2O_4$for the $CO_2$decomposition were investigated. XRD results of the synthesized ferrites showed a typical spinel structure of ferrite and the particle size was very small as about 6~10 nm. BET surface area of the ternary ferrites was not affected by the impregnation of Pt and Pd. The reactivity of the $CO_2$decomposition to carbon was improved by the impregnation of the noble metals of Pd and Pt. The effect of Pd-impregnation on the $CO_2$decomposition rate was higher than Pt-impregnation.

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Complex Permeability Analysis of NiCuZn Ferrites (NiCuZn 계 페라이트의 조성에 따른 복소투자율 변화 해석)

  • 남중희;오재희
    • Journal of the Korean Magnetics Society
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    • v.6 no.6
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    • pp.382-387
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    • 1996
  • The characteristics of the complex permeability of ${(Ni_{x}Cu_{0.2}Zn_{0.8-x}O)}_{1-w}{(Fe_{2}O_{3})}_{1+w}$ with various Ni and $Co_{3}O_{4}$ contents were investigated in this work. It is found that the NiCuZn ferrites with $x{\geq}0.6$ have a relatively small peak width of the imaginary part of permeability $\mu$". The resonance frequency is increased as Ni content becomes higher, where the loss is low. The $\mu$" value decreases with increasing FezO, deficiency, but the resonance frequency($f_{\mu"max}$) is only slightly affected by $Fe_{2}O_{3}$ deficiency. In case of $Co_{3}O_{4}$ addition to the NiCuZn ferrites, the $f_{\mu"max}$ increases since the initial permeability decreases with the amount of $Co_{3}O_{4}$. It is concluded that the Ni content in the NiCuZn ferrite is a dominant factor for the total loss of these spinel ferrites.

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High-frequency Magnetic Properties of Ni-Zn-Co Ferrites Used for Mangetic Shielding in NFC (NFC의 자기 차폐용 Ni-Zn-Co 페라이트 자성체의 고주파 자기특성)

  • Ryu, Yo-Han;Kim, Sung-Soo
    • Journal of Powder Materials
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    • v.21 no.6
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    • pp.429-433
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    • 2014
  • This study investigated the magnetic properties and frequency dispersion of complex permeability of Ni-Zn-Co ferrites used for magnetic shielding in near field communication (NFC) system. The sintered specimens of $(Ni_{0.7}Zn_{0.3})_{1-x}Co_xFe_2O_4$ composition were prepared by the conventional ceramic processing. The coercive force and saturation magnetization were measured by vibrating sample magnetometer. The complex permeability was measured by RF impedance analyzer in the range of 1 MHz~1.8 GHz. The coercive force increased and saturation magnetization decreased with increasing the Co substitution. The real and imaginary parts of complex permeability decreased and the resonance frequency increased with Co substitution, which was attributed to the increase in crystal anisotropy field and reduction in saturation magnetization. The effect of Co substitution could be found in reducing the magnetic loss to nearly zero at the operating frequency of NFC (13.56 MHz).

Nickel Substitution Effects on Nano-sized Co, Mn and MnZn Ferrites Synthesized by Sol-gel Method

  • Choi, Won-Ok;Kwon, Woo Hyun;Chae, Kwang Pyo;Lee, Young Bae
    • Journal of Magnetics
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    • v.21 no.1
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    • pp.40-45
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    • 2016
  • Nickel substituted nano-sized ferrite powders, $Co_{1-x}Ni_xFe_2O_4$, $Mn_{1-x}Ni_xFe_2O_4$ and $Mn_{1-2x}Zn_xNi_xFe_2O_4$ ($0.0{\leq}x{\leq}0.2$), were fabricated using a sol-gel method, and their crystallographic and magnetic properties were subsequently compared. The lattice constants decreased as quantity of nickel substitution increased, while the particle size decreased in $Co_{1-x}Ni_xFe_2O_4$ ferrite but increased for the $Mn_{1-x}Ni_xFe_2O_4$ and $Mn_{1-2x}Zn_xNi_xFe_2O_4$ ferrites. For the $Co_{1-x}Ni_xFe_2O_4$ and $Mn_{1-x}Ni_xFe_2O_4$ ($0.0{\leq}x{\leq}0.2$) ferrite powders, the $M{\ddot{o}}ssbauer$ spectra could be fitted as the superposition of two Zeeman sextets due to the tetrahedral and octahedral sites of the $Fe^{3+}$ ions. However, the $M{\ddot{o}}ssbauer$ spectrum of $Mn_{0.8}Zn_{0.1}Ni_{0.1}Fe_2O_4$ consisted of two Zeeman sextets and one single quadrupole doublet due to the ferrimagnetic and paramagnetic behavior. The area ratio of the $M{\ddot{o}}ssbauer$ spectra could be used to determine the cation distribution equation, and we also explain the variation in the $M{\ddot{o}}ssbauer$ parameters by using this cation distribution equation, the superexchange interaction and the particle size. The saturation magnetization decreased in the $Co_{1-x}Ni_xFe_2O_4$ and $Mn_{1-2x}Zn_xNi_xFe_2O_4$ ferrites but increased in the $Mn_{1-x}Ni_xFe_2O_4$ ferrite with nickel substitution. The coercivity decreased in the $Co_{1-x}Ni_xFe_2O_4$ and $Mn_{1-2x}Zn_xNi_xFe_2O_4$ ferrites but increased in the $Mn_{1-x}Ni_xFe_2O_4$ ferrite with nickel substitution. These variations could thus be explained by using the site distribution equations, particle sizes and spin magnetic moments of the substituted ions.

Magenetic Properties of Co, Ni and Ca Substituted Mn-Zn Ferrite (Co, Ni 및 Ca를 첨가한 Mn-Zn 페라이트의 자기적 성질)

  • 하태욱;이정식
    • Journal of the Korean Magnetics Society
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    • v.5 no.1
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    • pp.15-20
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    • 1995
  • We have prepared 20 kinds of Mn-Zn ferrites as content of CaO(0.1 mol%), NiO(0.0~0.60 mol%) and CoO(0.0~0.8 mol%) adding by the coprecipitation method and studied the magnetic properties as content of CaO, NiO and CoO adding. Initial permeability decrease as the content of NiO and CoO adding increases, while Curie tem~ perature increase as the content of NiO and CoO adding increases. $(H_{c})$, $(B_{s})$ and $(W_{h})$ increase as content of NiO adding increases.

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