• 한국분말재료학회지
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• 제19권5호
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• pp.338-342
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• 2012

A novel chemical method was evaluated to fabricate the ultrafine tungsten heavy alloy powders with bater-base solution made from the ammonium metatungstate (AMT), iron(II) chloride tetrahydrate ($FeCl_2{\cdot}4H_2O$), nickel(II) chloride hexahydrate ($NiCl_2{\cdot}6H_2O$) as source materials and the sodium tungstate dihydrate ($NaWO_4{\cdot}2H_2O$) as Cl-reductant. In the preparation of mixtures the amounts of the source components were chosen so as to obtain alloy of 93W-5Ni-2Fe composition(wt.%). The obtained powders were characterized by X-ray diffraction, XRF, field-emission scanning microscope (FESEM), and chemical composition was analyzed by EDX.

• Journal of Magnetics
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• 제2권4호
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• pp.130-134
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• 1997

The amorphous Co-based alloy Co66Fe4Ni1B15Si14 (Metglas 2714A) is a suitable magnetic core material for high frequency operation. Appreciable reduction of the coercive force can be achieved by proper heat treatment. In this study, samples annealed at wide temperature range were analyzed using differential scanning calorimetry, high frequency B-H loop tester, X-ray diffractometer and resistivity meter. The results show that coercive force at 10 kHz decreases with in-creasing annealing temperature up to 773 K, but dramatically increases above this temperature. The squareness shows that the magnetic anisotropy on longitudinal direction of the as-cast state remains up to 773 K. Above this temperature, it decreases down to 0.5 that represents random distribution of magnetic domains. The crystallization abruptly occurs between 781 K and 783 K.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.270-273
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• 2009

This work describes a method of determining material parameters included in recrystallization and grain growth models. Focus is on the recrystallization and grain growth models of Ni-Fe base superalloy, Alloy 718. High temperature compression tests at different strain, strain rate and temperature conditions were chosen to determine the material parameters of dynamic recrystallization model. The critical strain and dynamically recrystallized grain size and fraction at various process variables were quantitated with the microstructual analysis and strain-stress relationships of the compression tests. Besides, isothermal heat treatments were utilized to fit the material constants included in the grain growth model. Verification of the determined material parameters is carried out by comparing the measured data obtained from other compression tests.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.117-118
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• 2013

증기발생기 화학세정 모사 장치를 이용하여 고농도 화학세정(EPRI/SGOG) 용액인 EDTA(20%)가 인위적으로 제작한 결합 시편에 미치는 영향 평가를 수행하였다. 평가 방법은 세정 전 후 표면 산화막 성분, ECT 분석값 비교, 증기발생기 구성 재료 부식률를 이용하였다. 화학세정 전후 부식률은 A508은 $8.023{\mu}m$, Alloy 600(HTMA)은 $0.007{\mu}m$이며 갈바닉 시편의 경우 $63.193{\mu}m$로 모두 부식 허용치 이내이다. 표면 산화막 성분 및 ECT 분석값 역시 변함이 없었다. 이와 같은 결과로 화학세정 용액인 EDTA는 결함 튜브에 미치는 영향이 없는 것으로 판단된다.

• 한국분말재료학회지
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• 제26권5호
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• pp.389-394
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• 2019

In the present study, we have investigated the effect of sintering process conditions on the stability of the austenite phase in the nanocrystalline Fe-5wt.%Mn-0.2wt.%C alloy. The stability and volume fraction of the austenite phase are the key factors that determine the mechanical properties of FeMnC alloys, because strain-induced austenite-martensite transformation occurs under the application of an external stress at room temperature. Nanocrystalline Fe-5wt.%Mn-0.2wt.%C samples are fabricated using the spark plasma sintering method. The stability of the austenite phase in the sintered samples is evaluated by X-ray diffraction analysis and hardness test. The volume fraction of austenite at room temperature increases as the sample is held for 10 min at the sintering temperature, because of carbon diffusion in austenite. Moreover, water quenching effectively prevents the formation of cementite during cooling, resulting in a higher volume fraction of austenite. Furthermore, it is found that the hardness is influenced by both the austenite carbon content and volume fraction.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.344-345
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• 2015

Various concentration of copper was dopped in Fe-35%Ni thin sheet by electroforming and their electromagnetic, surface properties were determined. Microstructure observation by scanning electron microscopy revealed that the thin sheet had columnar grains with about 150 nm long. Phase analysis by X-ray diffractometry revealed that the alloy thin sheets were fine crystalline. The average surface roughnesses measured by atomic force microscopy (AFM) were about 14.38 nm. Nano hardnesses determined by tribo-nano indenter were 4.13 GPa. The surface resistances were 2.28 ohm/sq. The maximum magnetization, residual magnetization and coercive force depended on the copper concentration.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.107-107
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• 2015

In order to investigate electrochemical behavior and biocompatibility of Co-Cr dental alloy by electrochemical corrosion test and MTT assay, the xCo-25Cr-yW-zNi alloys were used in this study. Samples of Co-Cr-W-Ni alloys were manufactured using arc melting furnace. The microstructure of the alloys was examined by optical microscopy (OM), Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), MTT assay, and corrosion test. Corrosion resistance increased slightly as cobalt (Co) content increased. And bioactivity was concerned with nickel (Ni) and tungsten (W). Biocompatibility of Co-Cr alloy depended on Ni and W contents.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.150.2-150.2
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• 2007

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1998년도 춘계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.24-24
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• 1998

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 전기공동학술대회 논문집
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• pp.295-295
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• 2011