• 한국재료학회지
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• 제16권2호
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• pp.137-143
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• 2006

The effects of Cu and Fe additions on the thermal stability, microstructure and mechanical properties of $Al_{85}-Ni_{8.5}-Mm_{6.5},\;Al_{84}-Ni_{8.5}-Mm_{6.5}Cu_1,\;Al_{84}-Ni_{8.5}-M_{m6.5}Fe_1$ alloys, manufactured by gas atomization, degassing and hot-extrusion were investigated. Gas atomization, with a wide super-cooled liquid region, allowed the alloy powders to exhibit varying microstructure depending primarily on the powder size and composition. Al hotextruded alloys consisted of homogeneously-distributed fine-grained fcc-Al matrix and intermetallic compounds. A substitution of 1 at.% Al by Cu increased the thermal stability of the amorphous phase and produced alloy microstructure with smaller fcc-Al grains. On the other hand, the same substitution of 1 at.% Al by Fe decreased the stability of the amorphous phase and produced larger fcc-Al grains. The formation of intermetallic compounds such as $Al_3Ni,\;Al_{11}Ce_3\;and\;Al_{11}La_3$ was suppressed by the addition of Cu or Fe. Among the three alloys examined, the highest Vickers hardness and compressive strength were obtained for $Al_{84}-Ni_{8.5}-M_{m6.5}Cu_1$ alloy, and related to the finest fcc-Al grain size attained from increased thermal stability with Cu addition.

• 한국수소및신에너지학회논문집
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• 제9권4호
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• pp.135-141
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• 1998

Fe-Ti계 수소저장합금 전극의 방전특성을 개선하기 위하여 Ni을 첨가한 $TiFe_{1-x}Ni_x$ 합금을 제조하여 방전특성과 열처리 온도에 따른 변화를 조사하였다. 합금의 조성은 x = 0.1에서 0.6까지 0.1 단위씩 변화시킨 6가지 조성을 선택하여 각각에 대한 초기방전용량과 충방전사이클에 따른 용량변화를 조사하였다. 초기방전용량은 Ni의 조성이 클수록 증가하다가 x = 0.6 에서 다시 감소하였으며 Ni의 조성이 증가함에 따라 사이클특성은 전반적으로 매우 악화되었다. 열처리온도가 사이클 특성에 미치는 영향을 조사하기 위하여 초기용량이 가장 우수한 $TiFe_{0.5}Ni_{0.5}$ 합금에 대하여 $700{\sim}900^{\circ}C$ 의 온도범위에서 열처리를 시행한 후 방전특성을 조사하였다. 열처리에 의해서 초기용량은 감소되지만 사이클 특성은 현저히 개선되었다. $700{\sim}850^{\circ}C$의 온도범위에서 1시간 열처리한 전극의 경우에 사이클이 진행되면서 방전용량이 크게 회복되었으며, 열처리한 표면조직을 SEM 으로 관찰해 본 결과 이는 충분한 전극강도 및 기공율에 기인한 것으로 생각되었다. $900^{\circ}C$에서 1시간 열처리한 전극은 충분한 기공율을 갖지 못하여 방전특성이 좋지 않음을 알 수 있었다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2004년도 동계학술연구발표회 논문개요집
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• pp.91-92
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• 2004

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.491-492
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• 2008

The effect of B on the hot ductility of Fe-29Ni-17Co Kovar alloy and the mechanism of high temperature deformation behavior were investigated. Hot-tensile test was carried out at the temperature range of $900^{\circ}C-1200^{\circ}C$. Optical microscopy and scanning electron microscopy were used to investigate the microstructure and fracture during hot deformation. The hot ductility of Kovar alloy was drastically increased with the addition of Boron. The improvement of hot ductility results from the grain boundary migration mainly due to the dynamic recrystallization at lower temperature range($900^{\circ}C$).

• 한국표면공학회지
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• 제31권5호
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• pp.297-303
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• 1998

The influences of vanadium addition on the cavitation erosion resistance pf Fe-Cr-Ni-Si-C hardfacing alloy were investigated using a vibratory apparatus up to 30 hrs. It was shown that 1wt.%V additioned alloy improved the resistance to cavitation damage. However, further increase in V content up to 2wt.% reduced the cavitation erosion resistance. It was considered that the addition of V developed the cavitation erosion resistance by reducing the stacking fault energy of Fe-Cr-Ni-Si-C alloy. However, the further increase in V content seemed to reduce the cavitation erosion resistance by increasing the matrix/carbide interfacial area, which was the preferential sites of the cavitation damage.

• 전기화학회지
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• 제5권1호
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• pp.17-20
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• 2002

다양한 조성의 CoFeNi합금이 chloride bath와 sulfate bath에서 전해도금 되어졌고, 합금의 도금 특성과 자기특성이 관찰되어졌다. CoFeNi합금 박막의 전해도금에 있어서 Fe조성의 증가는 chloride bath에서보다 sulfate bath에서 빠르게 증가하였다. 전류효율은 큰 변화가 보이지 않는 chloride bath와 달리 sulfate bath에서는 $750\%$에서 $50\%$로 큰 폭으로 감소하였다. Co, Fe, Ni조성이 $80\%,\;10\%,\;10\%$되는 CoFeNi합금이 이번 실험에서 가장 우수한 연자성 재료로 평가되었으며, 그때의 Coercivity는 3 Oe이고 높은 squareness값을 보였다

• 대한치과보철학회지
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• 제27권1호
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• pp.49-54
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• 1989

The purpose of this study was to investigate the interfacial elemental change when solding the Ni-Co-Cr dental removable partial denture alloy and Fe-Cr-Ni wrought wire alloy with Ag-Cu-Zu Silver solder, by EDXA, EPMA, to investigate the appropriateness of clinical usefullness for repair the fractured clasps of removable partial dentive. The result of this study was as follows: 1. The Ni element of major component of Ticonium penetrate into the silver solder 2. The movement Age element of silver solder into Fe-Cr-Ni wire was not significant, by EDXA and EPMA.

• 한국재료학회지
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• 제25권8호
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• pp.391-397
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• 2015

NiO catalysts/$Al_2O_3$/FeCrAl alloy foam for hydrogen production was prepared using atomic layer deposition (ALD) and subsequent dip-coating methods. FeCrAl alloy foam and $Al_2O_3$ inter-layer were used as catalyst supports. To improve the dispersion and stability of NiO catalysts, an $Al_2O_3$ inter-layer was introduced and their thickness was systematically controlled to 0, 20, 50 and 80 nm using an ALD technique. The structural, chemical bonding and morphological properties (including dispersion) of the NiO catalysts/$Al_2O_3$/FeCrAl alloy foam were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy and scanning electron microscopy-energy dispersive spectroscopy. In particular, to evaluate the stability of the NiO catalysts grown on $Al_2O_3$/FeCrAl alloy foam, chronoamperometry tests were performed and then the ingredient amounts of electrolytes were analyzed via inductively coupled plasma spectrometer. We found that the introduction of $Al_2O_3$ inter-layer improved the dispersion and stability of the NiO catalysts on the supports. Thus, when an $Al_2O_3$ inter-layer with a 80 nm thickness was grown between the FeCrAl alloy foam and the NiO catalysts, it indicated improved dispersion and stability of the NiO catalysts compared to the other samples. The performance improvement can be explained by optimum thickness of $Al_2O_3$ inter-layer resulting from the role of a passivation layer.

• 한국표면공학회지
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• 제27권6호
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• pp.319-326
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• 1994

The effects of electrolysis conditions on the composition and preferred orientation of Ni-Fe alloy were studied using the sulfate-chloride baths paddle agitated. Cathode current efficiency is higher in the deposits from bath 2 than that of deposits from bath 1. The Fe content of alloy deposits from bath 2 is nearly constant(19∼21wt.%) in the wide range of current density, while it decreases noticeably with current density in the deposits from bath 1. The variation of Fe content at the edge of specimen is lower in deposits from bath 2 than those from bath 1. The alloy deposits show (111) & (200) preferred orientation for the deposits from bath 1 and bath 2 respectively.

• 한국재료학회지
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• 제28권10호
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• pp.595-600
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• 2018

This study investigates the microstructural properties of CoCrFeMnNi high entropy alloy (HEA) oxynitride thin film. The HEA oxynitride thin film is grown by the magnetron sputtering method using nitrogen and oxygen gases. The grown CoCrFeMnNi HEA film shows a microstructure with nanocrystalline regions of 5~20 nm in the amorphous region, which is confirmed by high-resolution transmission electron microscopy (HR-TEM). From the TEM electron diffraction pattern analysis crystal structure is determined to be a face centered cubic (FCC) structure with a lattice constant of 0.491 nm, which is larger than that of CoCrFeMnNi HEA. The HEA oxynitride film shows a single phase in which constituting elements are distributed homogeneously as confirmed by element mapping using a Cs-corrected scanning TEM (STEM). Mechanical properties of the CoCrFeMnNi HEA oxynitride thin film are addressed by a nano indentation method, and a hardness of 8.13 GPa and a Young's modulus of 157.3 GPa are obtained. The observed high hardness value is thought to be the result of hardening due to the nanocrystalline microstructure.