• Title/Summary/Keyword: 니켈 페라이트

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The Effect of Non-stoichiometry on the Microwave Absobing Properties of Ni-Zn Ferrites. (비화학양론적 조성이 니켈-아연 페라이트의 전파흡수특성에 미치는 영향)

  • 조성백;오재희
    • Journal of the Korean Magnetics Society
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    • v.5 no.1
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    • pp.21-26
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    • 1995
  • The systematic variation of complex permeability and complex permittivity and their relationship with micro-wave absorbing properties are investigated in sintered Ni-Zn ferrites of non-stoichiometric composition. The specirrens of ${(Ni_{0.5}Zn_{0.5}O)}_{1-x}(Fe_{2}O_{3})_{1+x}$ spinels were prepared by a conventional ceramic processing technique. In the present study. complex permeability and permittivity can be controlled by the variation of ${\alpha}-Fe_{2}O_{3}$ contents in the spinel lattice. The primary effect of the excess ${\alpha}-Fe_{2}O_{3}$ is to increase the dielectric constant. while the notable decrease of magnetic loss is observed in the iron-deficient ferrites. The results suggest that the matching fre-queocyand matching thickness could be controlled by the variation of ${\alpha}-Fe_{2}O_{3}$ contents in the Ni-Zn ferrite.

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A Study of cut off effect of ultraviolet in sunglasses lens coated with nickel-ferrite thin film NxFe3-xO4 (니켈페라이트 박막 NxFe3-xO4를 이용한 선글라스 렌즈의 자외선 차단효과에 대한 연구)

  • Ha, T.W.;Lee, Y.H.;Choi, K.S.;Cha, J.W.
    • Journal of Korean Ophthalmic Optics Society
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    • v.8 no.2
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    • pp.25-29
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    • 2003
  • Nickel-ferrite $Ni_xFe_{3-x}O_4$ thin films with several composition for Ni on glass substrate was prepared by ferrite plating method in order to make sunglass which cut off ultraviolet and shield electromagnetic field. It has single phase of polycrystalline spinel structure and has gloss as mirror and has high hardness which is no scratch while scraping by using nail. The transmittance of nickel-ferrite thin film is lowered to zero below 400 nm manifestly. And it shows that the nickel-ferrite thin film in nickel composition rate x = 0.09 was most cut oil ultraviolet when compared with goods of other company in the cut off effect of ultraviolet. Therefore, sunglasses coated with $Ni_xFe_{3-x}O_4$ thin film can be used in removing ultraviolet and electromagnetic field.

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The effect of sigma phases formation depending on Cr/Ni equivalent ratio in AISI 316L austenitic stainless steel weldments. (AISI 316L 용접부의 시그마상 형성에 영향을 미치는 크롬/니켈 당량비)

  • Kim, Y.H.;Jang, A.Y.;Choi, C.H.;Kang, D.H.;Jeon, J.H.;Byun, J.C.;Jung, G.H.;Lee, S.H.;Lee, H.W.
    • Proceedings of the KWS Conference
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    • 2010.05a
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    • pp.21-21
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    • 2010
  • AISI 316L 용접금속의 크롬/니켈 당량비에 따른 시그마상의 영향을 알아보기 위하여 응고모드가 다른 3종류의 플럭스 코어드 와이어를 제작하였다. AISI 316L 시편에 FCAW 프로세스를 적용한 용접재를 $650^{\circ}C$, $750^{\circ}C$, $850^{\circ}C$, $950^{\circ}C$에서 각 각 1H, 5H, 24H, 72H동안 열처리하였다. 크롬/니켈 당량비가 높을수록 즉, 크롬의 함량이 높아질수록 $\delta$-페라이트 함량은 증가하였으며, $\delta$-페라이트는 고온에서 시그마상으로 변태되었다. $\delta$-페라이트는 $650^{\circ}C$에서 가장 느리게 분해되었으며 $850^{\circ}C$에서 가장 활발히 분해되었다. 용접부의 특성상 크롬과 니켈 등의 합금원소에 의하여 응고온도범위가 넓어져 $950^{\circ}C$에서도 시그마상이 석출되었으며, 5시간 이상 유지 시 구형으로 존재하였다. 충격시험 시 시그마상에 의해 취약해진 inter-dendrite 를 따라 파면이 형성되었으며, $-100^{\circ}C$이하의 극저온에서는 시그마상의 양과 무관하게 충격흡수에너지는 0에 가까워졌다. 하지만 3%미만의 $\delta$-페라이트를 함유하는 AF모드에서 발생한 DDC와 미량의 시그마상은 충격흡수에너지에 결정적인 영향을 미치지 않았다.

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Manufacture of Nano-Sized Ni-ferrite Powder from Waste Solution by Spray Pyrolysis Process (분무열분해 공정에 의한 폐액으로부터 니켈 페라이트 나노 분말 제조)

  • Yu Jae-Keun;Suh Sang-Kee;Kang Seong-Gu;Kim Jwa-Yeon;Park Si-Hyun;Park Yaung-Soo;Choi Jae-Ha;Sohn Jin-Gun
    • Resources Recycling
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    • v.12 no.4
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    • pp.20-29
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    • 2003
  • In order to efficiently recycle the waste solution resulting from shadow mask processing, nano-sized Ni-ferrite powder was fab-ricated through spray pyrolysis process. The average particle size of the powder was below 100nm. In this study, the effects of the reaction temperature. the concentration of raw material solution and the injection speed of solution on the properties of powder were respectively investigated. As the reaction temperature increased from $800^{\circ}C$ to $1100^{\circ}C$, average particle size of the powder significantly Increased and power structure became more solid, whereat its specific surface area was greatly reduced. Formation rate and crystallization of($NiFe_2$$O_4$) phale increased along with the temperature rise. As the concentrations of iron and nickel components in wastere solution increased, particle size of the powder became larger, particle size distribution became more irregular, and specific surface area was reduced. Formation rate and crystallization of $NiFe_2$$O_4$ phase increased significantly along with the increase of the concentration of solution. As the inlet speed of solution increased, particle size of the powder became larger, particle size distribution became wider, specific surface area was reduced and powder structure became less solid. As the inlet speed of solution decreased, formation rate and crystallization of $NiFe_2$$O_4$ phase significantly increased.

Substitution of Co on Magnetic Properties of Ni-Zn Ferrites (Co 치환에 따른 Ni-Zn Ferrites의 자기적 특성)

  • Park, H.Y.;Ahn, M.S.;Ahn, Y.W.;Lee, S.K.;Oh, Y.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07a
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    • pp.539-542
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    • 2004
  • 전자기기의 발달과 더불어 정보통신분야의 발달로 고주파 대역에서 우수하고 안정적인 Ni-Zn 페라이트를 제조하기 위해, Ni(니켈)의 일부를 코발트(Co)로 치환하여 결정자기이방성 상수 값을 증가시켜, 공명 주파수를 고주파 대역으로 높이고자 하였다. Co 함량이 증가함에 따라 투자율은 감소하는데, 이는 결정자기 이방성 상수를 크게 하여 공명 주파수를 높이는 결과를 보였으며, x=0.05에서 투자율 75, 공명 주파수 20MHz의 특성을 나타내었다.

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Study on the Simulation of Crud Formation using Piping Materials of Nuclear Power Plant in High Temperature Water (원자력 발전소 배관재를 이용한 고온 수화학 조건에서의 방사화 부식생성물 모사에 관한 연구)

  • Kim Sang Hyun;Kim In Sup;Lee Kun Jai
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.3 no.1
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    • pp.31-40
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    • 2005
  • High temperature - high pressure apparatus was developed to simulate nickel fewite corrosion products which were main compositions of the radioactive crud in the nuclear power plant. Corrosion product similar to the crud was obtained by a tube accumulator system. Nickel alloy (Inconel 690) and carbon steel (SA106 Gr. C) were corroded at 270 $\^{circ}C$ in the corrosion product generator. Ni ions and Fe ions dissolved by corrosion reaction were able to be transported to the accumulator because the crud generation mechanism was the solubility change with temperature. To evaluate the properties of simulated corrosion products, scanning electron microscope (SEM) observation and EDAX analysis were performed. SEM observation of corrosion product showed the needlelike or crystal structure of oxide depending on precipitating location. The crystal oxide was the nickel ferrite, which was similar to the crud in nuclear power plants.

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Fabrication of Nano-Sized Complex Oxide Powder from Waste Solution Produced during Shadow Mask Processing by Spray Pyrolysis Process (새도우마스크 제조 공정중 발생되는 폐액으로부터 분무열분해 공정에 의한 복합산화물 나노 분말 제조)

  • Yu Jae-Keun
    • Resources Recycling
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    • v.12 no.6
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    • pp.38-46
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    • 2003
  • In this study, nano-sized Ni-ferrite and $Fe_2$$O_3$+NiO powder was fabricated by spray pyrolysis process in the condition of 1kg/$\textrm{cm}^2$ air pressure using the Fe-Ni complex waste acid solution generated during the manufacturing process of shadow mask. The average particle size of the produced powder was below 100 nm. The effects of the reaction temperature, the concentration of raw material solution and the nozzle tip size on the properties of powder were studied. As the reaction temperature increased from $800 ^{\circ}C$ to $1100^{\circ}C$, the average particle size of the powder increased from 40 nm to 100 nm, the structure of the powder gradually became solid, yet the distribution of the particle size appeared more irregular. Along with the increase of the reaction temperature, the fraction of the Ni-ferrite phase were also on the rise, and the surface area of the powder was greatly reduced. As the concentration of Fe in solution increased from 20g/l to 200g/l, the average particle size of the powder gradually increased from 30 nm to 60 nm, while the distribution of the particle size appeared more irregular. Along with the increase of the concentration of solution, tie fraction of the Ni-ferrite phase was on the rise, and the surface area of the powder was greatly reduced. Along with the increase of the nozzle tip size, the distribution of the particle size appeared more irregular, yet the average particle size of the powder showed no significant change. As the nozzle tip size increased from 1 mm to 2 mm, the fraction of the Ni-ferrite phase showed no significant change, while the surface area of the powder slightly reduced. As the nozzle tip size increased to 3 mm and 5 mm, the fraction of the Ni-ferrite phase gradually reduced, and the surface area of the powder slightly increased.

An Experimental Study on Block Shear Fracture of Base Metal in Ferritic Stainless Steel Welded Connection (페라이트계 스테인리스강 용접접합부의 모재 블록전단파단에 관한 실험적 연구)

  • Kim, Tae Soo
    • Journal of Korean Society of Steel Construction
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    • v.28 no.5
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    • pp.303-312
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    • 2016
  • Many researches on the application of stainless steels as structural steels have been performed thanks to their material properties such as superior ductility and corrosion resistance. Ferritic stainless steels(STS430) with little or no nickel have been used increasingly in building structure because it is inexpensive compared to austenitic stainless steels(STS304) with nickel, but provide performances similar to the austenitic stainless steel. This paper deals with block shear fracture behavior of base metal in stainless steel welded connection. Although the block shear fracture behavior for welded connection due to stress triaxiality is different from that of bolted connection, the block shear strength of welded connection in current design specifications has been predicted based on that of bolted connection. The main parameters are weld length and welding process(Arc and TIG welds). The ultimate strengths of TIG welded specimens were higher than those of arc welded specimens and current design predictions by AISC, EC3 etc. were compared with test strengths.

A Study on Effect of Temperature on Particle Size Distribution of Nickel Ferrite (온도의 영향에 따른 니켈페라이트의 입자 크기 분포 연구)

  • Ahn, Hyung-Kyoung;Lee, In-Hyoung;Jeong, Hyun-Jun;Park, Byung-Gi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1768-1774
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    • 2008
  • The particulate behaviors of nickel ferrite were investigated under the simulated PWR shutdown chemistry conditions. Temperature of the simulated water with concentration of 0.1 ppm Li and 2,000 ppm B was dropped from $300^{\circ}C$ to $150^{\circ}C$ with a rate of $0.625^{\circ}C/min$ and then constantly maintained at $150^{\circ}C$ under the pressure of 2,500 psi. The on-line particle counting and the concentration measurement of nickel dissolved were performed under 5, 15 and 25 cc/kg $H_2O$ dissolved hydrogen. Experimental results showed that total particle count in the simulated water was not greatly changed for three hydrogen concentrations as temperature was decreased. However, particles were smaller as temperature was decreased and then maintained constantly. The degree of variation in particle size distribution was greater at 15 cc/kg $H_2O$ dissolved hydrogen than any other dissolved hydrogen concentrations. Concentration of nickel ion was increased as temperature was decreased and was higher at 15 cc/kg $H_2O$ dissolved hydrogen than any other dissolved hydrogen concentrations. Theses results show that nickel ferrite is unstable with temperature variation and at dissolved hydrogen concentration of 15 cc/kg $H_2O$.