• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.113-114
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• 2012

본 연구는 segment target을 사용하여 unbalanced magnetron sputtering을 활용하여 고 CrZr-Si-N 박막을 합성하고 박막의 미세구조 및 마모 특성을 연구하는데 그 목적이 있다. 박막의 Si 함량을 조절하기 위하여 각 segment target은 Cr,Zr을 일정vol% 유지하며 Si vol%만 변화하여 설계하였다. Si 함량별로 제작된 마모실험 시편의 미세구조는 XRD, FE-SEM, AFM, TEM을 통하여 분석하였으며, ball on disk type의 마모 시험기를 통해 그 마모 특성을 분석하였으며,

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.113-113
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• 2010

최근 태양전지 제작 등에 응용되고 있는 $NH_3/N_2/SiH_4$ 유도결합 플라즈마 방전에서 활성종의 플라즈마 변수 의존성을 이론적인 계산을 통해 분석한다. 먼저, 수집 및 계산 가공된 반응계수들에 대한 신뢰성을 검증하기위해 공간평균 전산모사를 수행하여 최종적으로 계산된 전자온도 및 밀도값들이 합리적인 범주에 속해 있는지 확인한다. 검증된 반응계수들을 바탕으로 공간평균 유체방정식에서 정상상태를 가정하여 중성종 및 활성종 밀도를 전자밀도 및 온도 등의 플라즈마 변수에 대한 함수로 표현하고, 이에 대한 수치해석적인 해를 얻음으로써 그 의존성을 분석해 본다.

• Journal of Magnetics
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• v.8 no.3
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• pp.113-117
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• 2003

$Co_{78-x}Pt_xB_{10}Si_{12}$ alloys were produced using the melt-spin process in order to study the crystallization behavior and ensuing magnetic properties of the $Co_{78-x}Pt_xB_{10}Si_{12}$ (Co-Pt) amorphous alloys as a function of the Pt content. We showed that when $\chi$ $>$ 15 well below its stoichiometric composition, CoPt crystallized in the amorphous alloy, thus greatly altering the crystallized microstructure and magnetic properties during annealing. Below this composition, the main crystallization product was Co with Pt dissolved in its lattice. In spite of the nucleation of CoPt with high magnetic anisotropy, the highest coercivity was obtained when x was 15. It was also concluded that the Pt addition deteriorated the glass stability, triggering the devitrification at a progressively lower temperature.

• Journal of Korea Foundry Society
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• v.40 no.4
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• pp.113-117
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• 2020

A series of Fe-P-B and Fe-Si-B amorphous alloys with high Fe contents exceeding 90 wt.% was successfully prepared by combining flux treatment and melt-spinning technique. The effects of Fe content and the flux treatment on the thermal and magnetic properties of amorphous alloys were studied. The glass-forming ability and the thermal stability of amorphous ribbons can be improved by a flux treatment, revealing the effective removal of heterogeneous nucleation sites in the ribbons through the flux treatment. It was found that Fe-Si-B ribbons exhibit higher saturation magnetization levels than Fe-P-B ribbons.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.113.2-113.2
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• 2014

Heat is a familiar form of energy transported from a hot side to a colder side of an object, but not a notion associated with microscopic measurements of electronic properties. A temperature difference within a material causes charge carriers, electrons or holes, to diffuse along the temperature gradient inducing a thermoelectric voltage. Here we show that local thermoelectric measurements can yield high sensitivity imaging of structural disorder on the atomic and nanometre scales. Using this imaging technique, we discovered a defect-mediated dimensional evolution of strain-response patterns in epitaxial graphene with increasing thickness.

• Journal of the Korean Chemical Society
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• v.39 no.4
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• pp.312-317
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• 1995

• Proceedings of the Korean Vacuum Society Conference
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• 1999.02a
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• pp.143-143
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• 1999

• Korean Journal of Materials Research
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• v.28 no.2
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• pp.113-117
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• 2018

Effects of annealing temperature on the microstructure and mechanical properties through thickness of a cold-rolled Cu-3.0Ni-0.7Si alloy were investigated in detail. The copper alloy with thickness of 3 mm was rolled to 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5h at $200{\sim}900^{\circ}C$. The microstructure of the copper alloy after annealing was different in thickness direction depending on an amount of the shear and compressive strain introduced by rolling; the recrystallization occurred first in surface regions shear-deformed largely. The hardness distribution of the specimens annealed at $500{\sim}700^{\circ}C$ was not uniform in thickness direction due to partial recrystallization. This ununiformity of hardness corresponded well with an amount of shear strain in thickness direction. The average hardness and ultimate tensile strength showed the maximum values of 250Hv and 450MPa in specimen annealed at $400^{\circ}C$, respectively. It is considered that the complex mode of strain introduced by rolling effected directly on the microstructure and the mechanical properties of the annealed specimens.

• Journal of Industrial Technology
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• v.19
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• pp.107-113
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• 1999

The microstructural evolution during mechanical alloying of elemental Fe and Si powders, average composition $Fe_{30}Si_{70}$ and $Fe_{50}Si_{50}$, has been investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Differential scanning calorimetry (DSC). Mechanical alloying was performed by using a SPEX 8000 Mixer/Mill under argon atmosphere with/without hexane as a process control agent (PCA). In the presence of PCA, the milling process was dominated by fracture resulting in the decrease in particle size to about $1{\mu}m$. The structural development with milling time depended on the average composition of starting powders. The mixture of $Fe_{50}Si_{50}$ and $Fe_{30}Si_{70}$ resulted in the formation of FeSi(${\varepsilon}$ - phase) and $FeSi_2$(${\beta}$ - phase), respectively. In the case of $Fe_{33.3}Si_{66.7}$, a mixture and $FeSi_2({\beta})$ was formed. These results were discussed by considering the thermodynamics and kinetics concerning the milling process.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.06a
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• pp.111-113
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• 2011

변압기, 전동기 등의 에너지 효율을 향상시키기 위해 400 Hz 이상의 주파수에서 사용하는 자성코어 부품의 수요가 증가함에 따라 Si함량이 높은 연자성 코어에 대한 관심이 증가하고 있으며 냉간압연이 어려운 Fe-6.5wt.%Si의 경제적이고 생산성이 높은 분말 성형공정, 주파수에 따른 철손인자들의 영향 및 미세구조 제어에 대한 연구가 체계적이고 지속적 수행되고 있으며 흥미로운 연구결과가 도출되고 있다.