• 한국분말재료학회지
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• 제26권4호
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• pp.299-304
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• 2019

Nb-Si-B alloys with Nb-rich compositions are fabricated by spark plasma sintering for high-temperature structural applications. Three compositions are selected: 75 at% Nb (Nb0.7), 82 at% Nb (Nb1.5), and 88 at% Nb (Nb3), the atomic ratio of Si to B being 2. The microstructures of the prepared alloys are composed of Nb and $T_2$ phases. The $T_2$ phase is an intermetallic compound with a stoichiometry of $Nb_5Si_{3-x}B_x$ ($0{\leq}x{\leq}2$). In some previous studies, Nb-Si-B alloys have been prepared by spark plasma sintering (SPS) using Nb and $T_2$ powders (SPS 1). In the present work, the same alloys are prepared by the SPS process (SPS 2) using Nb powders and hypereutectic alloy powders with composition 67at%Nb-22at%Si-11at%B (Nb67). The Nb67 alloy powders comprise $T_2$ and eutectic ($T_2+Nb$) phases. The microstructures and hardness of the samples prepared in the present work have been compared with those previously reported; the samples prepared in this study exhibit finer and more uniform microstructures and higher hardness.

• Journal of Magnetics
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• 제16권3호
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• pp.211-215
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• 2011

The dynamic magnetostriction characteristics of an Fe-based nanocrystalline FeCuNbSiB alloy are investigated as a function of the dc bias magnetic field. The experimental results show that the piezomagnetic coefficient of FeCuNbSiB is about 2.1 times higher than that of Terfenol-D at the low dc magnetic bias $H_{dc}$ = 46 Oe. Moreover, FeCuNbSiB has a large resonant dynamic strain coefficient at quite low Hdc due to a high mechanical quality factor, which is 3-5 times greater than that of Terfenol-D at the same low $H_{dc}$. Based on such magnetostriction characteristics, we fabricate a new type of transducer with FeCuNbSiB/PZT-8/FeCuNbSiB. Its maximum resonant magnetoelectric voltage coefficient achieves ~10 V/Oe. The ME output power reaches 331.8 ${\mu}W$ at an optimum load resistance of 7 $k{\Omega}$ under 0.4 Oe ac magnetic field, which is 50 times higher than that of the previous ultrasonic-horn-substrate composite transducer and it decreases the size by nearly 86%. The performance indicate that the FeCuNbSiB/PZT-8/FeCuNbSiB transducer is promising for application in highly efficient magnetoelectric energy conversion.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.786-787
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• 2006

The magnetic inductance of nanocrystalline $Fe_{73}Si_{16}B_7Nb_3Cu_1$ and an amorphous FeSiB powder sheet has been investigated to identify RFID performance. The powder was mixed with binder and solvent and tape-casted to form films. Results show annealing significantly influenced on the inductance of the material. The surface oxidation of the particles was the main reason for the reduced inductance. The maximum inductance of $Fe_{73}Si_{16}B_7Nb_3Cu_1$ alloy was about $88{\mu}H$ at 17.4 MHz, about 65% greater compared to the FeSiB alloy. The higher inductance in the nanocrystalline alloy indicates it may be used as a potential replacement of current RFID materials.

• Journal of Magnetics
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• 제14권4호
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• pp.155-160
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• 2009

This study examined the effects of a decrease in thickness of magnetic alloy flakes on the electromagnetic wave absorption characteristics of nanocrystalline $Fe_{73.5}Cu_1Nb_3Si_{15.5}B_7$ (at.%) alloy flakes/polymer composite sheets available for a quasi-microwave band. The thickness of FeCuNbSiB alloy flakes decreased to 1-2 $\mu$m with increasing milling time up to 24 h, and the composite sheet including alloy flakes milled for 24 h exhibited considerably enhanced power loss properties in the GHz range compared to the sheets having non-milled alloy powders. Although a considerable increase in loss factor upon milling was observed in the narrow frequency range of 4-6 GHz, there was no correlation between the complex permeability and flake thickness. However, the complex permittivity increased with increasing milling time, and there was good agreement between the milling time and the frequency dependences of the complex permittivity and power loss.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1992년도 추계연구발표회 논문개요집
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• pp.60-61
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• 1992

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1993년도 춘계연구발표회 논문개요집
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• pp.62-63
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• 1993

• Corrosion Science and Technology
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• 제7권4호
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• pp.233-236
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• 2008

Halide-activated pack cementation was utilized to deposit B-doped silicide coating. The pack powders were consisted of $3Wt.c/oNH_4Cl$, 7Wt.c/oSi, $90Wt.c/oAl_2O_3+TiB_2$. B-doped silicide coating was consisted of two layers, an outer layer of $NbSi_2$ and an inner layer of $Nb_5Si_3$. Isothermal oxidation resistance of B-doped silicide coating was tested at $1250^{\circ}C$ in static air. B-doped silicide coating had excellent oxidation resistance, because continuous $SiO_2$ scale which serves as obstacle of oxygen diffusion was formed after oxidation.

• Journal of Magnetics
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• 제19권4호
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• pp.327-332
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• 2014

The effect of minor element additions (Ca, Al) on microstructural change and magnetic properties of Fe-Nb-Cu-Si-B alloy has been investigated, in this paper. The Fe-Si-B-Nb-Cu(-Ca-Al) alloys were prepared by arc melting in argon gas atmosphere. The alloy ribbons were fabricated by melt-spinning, and heat-treated under a nitrogen atmosphere at $520-570^{\circ}C$ for 1 h. The soft magnetic properties of the ribbon core were analyzed using the AC B-H meter. A differential scanning calorimetry (DSC) was used to examine the crystallization behavior of the amorphous alloy ribbon. The microstructure was observed by X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). The addition of Ca increased the electrical resistivity to reduce the eddy current loss. And the addition of Al decreased the intrinsic magnetocrystalline anisotropy $K_1$ resulting in the increased permeability. The reduction in the size of the ${\alpha}$-Fe precipitates was observed in the alloys containing of Ca and Al. Based on the results, it can be concluded that the additions of Ca and Al notably improved the soft magnetic properties such as permeability, coercivity and core loss in the Fe-Nb-Cu-Si-B base nanocrystalline alloys.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1165-1167
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• 1995

The Cu-Si alloy has been proposed as a new matrix materal for filamentary Nb-Ti wires in AC use. The Cu-Si alloy shows approprite mechanical and electrical properties, and is economically more favourable than the Cu-Ni alloy matrix used currently. Moreover, the addition of Si to Cu prevents the formation of intermetallic compounds around the filaments. After we investigated resistivity and hardness of Cu-Si alloy as matrix materal, investigated CuSi/NbTi interface reactions and superconductivities of superconducting wires that were made by various heat treatment.

• 한국자기학회지
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• 제3권2호
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• pp.130-134
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• 1993

초급냉법중 단롤법으로 제작한 $Fe_{73.5-X}Co_{X}Cu_{1}Nb_{3}Si_{13.5}B_{9}(x=2,\;4)$ 비정질 합금을 $400~650^{\circ}C$에서 열처리하여 자기적 특성을 조사하였다. $Fe_{71.5}Co_{2}Cu_{1}Nb_{3}Si_{13.5}B_{9}$ 비정질 합금의 최적 열처리 온도는 $550^{\circ}C$이며, 이온도에서 열처 리된 시료의 상대 투자율과 항자력은 1 kHz에서 각각 $1.1{\times}10^{4}$, 0.22 Oe이다. $Fe_{69.5}Co_{4}Cu_{1}Nb_{3}Si_{13.5)B_{9}$의 경우는 $600^{\circ}C$에서 열처리 했을때 상대 투자율과 항자력이 각각 $1.0{\times}10^{4}$, 0.19 Oe로 가장 우수한 연자성 특성을 보였다. X-선 실험결과, 이러한 연자성 특성의 향상은 $\alpha$-Fe(Si) 결정립의 형성에 의한 것임을 확인 할 수 있었으며, 강자성 공명 실험에 의하면 최적 열처리 조건은 공명 흡수선의 반치폭이 급격히 증가하기 직전의 온도임을 알 수 있었다.