• Proceedings of the Korean Magnestics Society Conference
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• 1993.03a
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• pp.66-67
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• 1993

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.128-132
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• 2007

The thermal and magnetic properties of amorphous (FeCo)SiBNb ribbon alloys with high glass forming ability have been investigated. The glass forming ability was enhanced by Co substitution in amorphous ($Fe_{1-X}Co_X)_{72}Si_4B_{20}Nb_4$ alloys with the thickness of about $40{\mu}m$. With the increase in Co content, the temperature range of supercooled liquid phase increased indicating the high glass forming ability of the Co-added alloys. Further the ac permeability increased, and the core loss decreased considerably by Co substitution, while small change in $B_8$ (magnetic flux density at 800 A/m) was observed. The frequency characteristics of permeability deteriorated as compared to conventional amorphous ribbon alloys with the thickness of about $20\;{\mu}m$ due to the increased skin effect.

• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.190-195
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• 1993

새로운 Fe기 초미세 결정립합금의 제조 가능성 및 자기특성에 관하여 조사하였다. 고포화자화 (Fe.$_{85}$Co.$_{15}$ )$_{80}$B$_{20}$ 비정질합금에서 천이금속을 약 10 at.% Al으로 치환한 (Fe.$_{85}$ Co.$_{15}$ )$_{70}$B$_{20}$Al$_{10}$ 합금은 급속응고에 의하여 비정질 기지내에 직접 .alpha. -Fe(Co)의 석출이 가능하다. 또한 (Fe.$_{85}$Co.$_{15}$ )$_{70}$B$_{20}$Al$_{10}$합금에 2~6 at.% Nb의 첨가는 급속 응고시 결정립성장을 억제하고 포화자왜를 약 6ppm이하로 감소시켜 자기 특성을 개선시킨다. 열처리에 의한 자기 특성은 Nb의 치환량이 증가할 수록 감소한다. 400 .deg. C에서 1시간 열처리한 (Fe.$_{85}$Co.$_{15}$ )$_{70}$ B$_{18}$ Al$_{10}$Nb$_{2}$합금은 평균 약 8nm이하의 .alpha. -Fe(Co) 결정립으로 구성된 초미세 결정립합금 으로 제조가 가능하며, 포화자속밀도, 철손 및 투자율 (f=50 kHz, B$_{m}$ =0.2 T)이 각각 1.2 T, 12W/kg 및 2.5 *$10^{4}$으로 가장 우수하다. 이는 Fe-Si-B-Nb-Cu 초미세결정립합금 및 영자왜 Co기 비정질합금과 거의 같은 자기특성을 나타낸다.다..다.다..낸다.다..

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.483-486
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• 1995

Soft magnetic properties of Fe-based (Fe,Co)-B-Al-M (M=Nb, Mo or Ta) nanocrystalline alloy have been investigated. The alloy obtained directly form the rapid solidification process. Microstructure of the alloy is a mixtu re of ultrafine bcc Fe(Co) nanocrystallines and a small amount of retained amorphous phase. Heat treatment of as-prepared alloys improves soft magnetic properties in high frequency range. ${(Fe_{.85}Co_{.15})}_{70}B_{18}Al_{10}Ta_{6}$ alloy alloy annealed at $500^{\circ}C$ for 1 h shows the most improved soth magnetic properties among the alloy examined. Average grain size of the nanocystalline is about 10 nm.

• Journal of the Korean Magnetics Society
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• v.3 no.2
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• pp.130-134
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• 1993

The magnetic properties of the amorphous $Fe_{73.5-X}Co_{X}Cu_{1}Nb_{3}Si_{13.5}B_{9}(x=2,\;4)$ alloys, fabricated by a single roll rapid quenching technique and annealed at $400~650^{\circ}C$, have been investigated. The optimum annealing temperature is $550^{\circ}C$ for the amorphous $Fe_{71.5}Co_{2}Cu_{1}Nb_{3}Si_{13.5}B_{9}$ alloy. The properties of the nanocrystalline $Fe_{71.5}Co_{2}Cu_{1}Nb_{3}Si_{13.5}B_{9}$ alloy show the relative permeability of $1.1{\times}10^{4}$ and the coercive force of 0.22 Oe at 1 kHz. When annealed at $600^{\circ}C$, the nanocrystalline $Fe_{69.5}Co_{4}Cu_{1}Nb_{3}Si_{13.5)B_{9}$ alloy shows the relative permeability of $1.0{\times}10^{4}$ and the coercive force of 0.19 Oe at 1 kHz. From the X-ray measurement, it is found that the remarkably improved soft magnetic properties are the effect of the formation of $\alpha$-Fe(Si) grain. By the results of FMR exper-imeIlt, the optimum annealing condition is just below temperature which the peak-to-peak line width of FMR spectrum increase rapidly.

• Journal of the Korean Magnetics Society
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• v.5 no.1
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• pp.38-41
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• 1995

The effects of Nb and Cu additives as will as substitutional Co into $Nd_{4}Fe_{85.5}B_{10.5}$ melt-spun alloy were studied aiming for finding a $\alpha$-Fe based Nd-Fe-B composite alloys with high energy product. The addition of Nb and Cu to $Nd_{4}Fe_{85.5}B_{10.5}$ decreased the average grain size and increased the coercivity up to 207kA/m(2.6kOe), Further-more, the substitution of Co for Fe in $Nd_{4}Fe_{82}B_{10}Nb_{3}Cu_{1}$ alloy resulted in the decrease of the average grain size (<20nm) and improved the hard magnetic properties. The remanence, coercivity and energy product of optimally annealed $Nd_{4}Fe_{74}Co_{8}B_{10}Nb_{3}Cu_{1}$ alloy were 1.345, 219kA/m(2.75kOe) and $95.5kJ/m^{3}$(12MGOe), respectively.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.496-499
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• 1995

Amorphous $Co_{80+x}TM_{12}B_{8-x}$ (TM = Ti, Zr, Hf, Nb and x = 0, 2, 4 at%) alloys were prepared by single roll melt spinning technique. Saturation magnetization of the amorphous ribbons was measured by SQUID and vibrating sample magnetometer from 5 to 800 K under applied fields up to 10 kOe. Typical thermo-magnetization curves were observed and the average values of the spectroscopic splitting g factor were estimated from the ferromagnetic resonance curve. For all the amorphous alloys studied here the saturation magnetization in the temperature range 5 K up to about $0.3T_{c}$ can be described by the Bloch relation: $M_{s}(T)\;=\;M_{s}(0)(1-BT^{3/2}-CT^{5/2})$. From the values of $M_{s}(0)$, B and spectroscopic splitting g factor the spin wave stiffness constants were calculated.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.5
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• pp.288-296
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• 2005

The corrosion behaviors of Zr-based alloys were very sensitive to their microstructures which were determined by manufacturing process. The specimens of Zr-based alloy named as HANA-4 for nuclear fuel cladding were investigated in order to get the optimized manufacturing process such as the intermediate annealing temperature and cold working steps after the ${\beta}$ quenching. From the microstructural analysis, cold worked microstructure of the samples was changed to the recrystallized microstructure by performed process. The corrosion behaviors of HANA-4 alloy were affected by the different manufacturing process. The ${\beta}$-Zr phase was formed in the matrix and the Nb concentration in the ${\beta}$-Zr phase was increased as progressing the manufacturing process. So, it was found that the corrosion rate of HANA-4 alloy was affected by the Nb concentration in the matrix.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.90-95
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• 2003

The present paper is to investigate the phase stability and soft magnetic properties of amorphous CoNbZr films when Pd is added as a substitution for CoNbZr alloys. The films were prepared by a RF magnetron sputtering method. The CoNbZrPd films deposited on Si wafers exhibited amorphous structures being independent upon the amount of Pd added in the films. On the addition of 4.34% Pd, the excellent soft magnetic characteristics of the films were observed with a coercive force of 0.54 Oe and an anisotropy field of 11 Oe, whereas a coercive force of 1 Oe and an anisotropy field of 3.5 Oe were shown in the film without the addition of Pd. The increased anisotropy field and low coercive force of the films may be attributed to the occupancy of Pd in the preferred sites parallel to the external magnetic field applied on the deposition process. A permeability of about 1100 was kept constant in the operation frequency ranging up to 100 MHz, which can be explained by the Landau-Lifshitz formula.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.54-58
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• 2002

The present paper is to investigate the phase stability and soft magnetic properties of amorphous CoNbZr films when Pd is added as a substitution for CoNbZr alloys. The films were prepared by a RF magnetron sputtering method. The CoNbZrPd films deposited on Si wafers exhibited amorphous structures being independent upon the amount of Pd added in the films. On the addition of 4.34% Pd, the excellent soft magnetic characteristics of the films were observed with a coercive force of 0.54 Oe and an anisotropy field of 11 Oe, whereas a coercive force of 1 Oe and an anisotropy field of 3.5 Oe were shown in the film without the addition of Pd. The increased anisotropy field and low coercive force of the films may be attributed to the occupancy of Pd in the preferred sites parallel to the external magnetic field applied on the deposition process. A permeability of about 1100 was kept constant in the operation frequency ranging up to 100 MHz, which can be explained by the Landau-Lifshitz formula.