• Title/Summary/Keyword: In situ microscopy

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In-situ Analysis on the Effect of Mo Underlayer on Hillock Formation Behavior in Al Thin Films (Al 박막의 힐록 형성에 미치는 Mo 하부층의 영향에 관한 실시간 분석)

  • Lee, Yong-Duck;Hwang, Soo-Jung;Lee, Je-Hun;Joo, Young-Chang;Park, Young-Bae
    • Korean Journal of Materials Research
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    • v.17 no.1
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    • pp.25-30
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    • 2007
  • The in-situ scanning electron microscopy observation of real-time hillock evolution in pure hi thin films on glass substrate during Isothermal annealing was analyzed quantitatively to understand the compressive stress relaxation mechanism by focusing on the effect of Mo interlayer between Al film and glass substrate. There is a good correlation between the hillock-induced stress relaxation by in-situ scanning electron microscopy observation ana the measured stress relaxation by wafer curvature method. It is also clearly shown that the existence of Mo interlayer plays an important role in hillock formation probably due to the large difference in interfacial diffusivity of Al films.

Microstructure and Tensile Property of In-Situ (TiB+TiC) Particulate Reinforced Titanium Matrix Composites (반응생성 합성에 의한 (TiB+TiC) 입자강화 Ti기 복합재료의 미세조직 및 인장특성 평가)

  • Choi, Bong-Jae;Kim, Young-Jig
    • Korean Journal of Metals and Materials
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    • v.48 no.8
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    • pp.780-789
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    • 2010
  • The aim of this study is to evaluate the microstructure and tensile property of in-situ (TiB+TiC) particulate reinforced titanium matrix composites (TMCs) synthesized by the investment casting process. Boron carbide ($1,500{\mu}m$ and $150{\mu}m$) was added to the titanium matrix during vacuum induction melting, which can provide the in-situ reaction of $5Ti+B_4C{\rightarrow}4TiB+TiC$. 0.94, 1.88 and 3.76 wt% of $B_4C$ were added to the melt. The phases identification of the in-situ synthesized TMCs was examined using scanning electron microscopy, an X-ray diffractometer, an electron probe micro-analyzer and transmission electron microscopy. Tensile properties of TMCs were investigated in accordance with the reinforcement size and volume fraction. The improvement of tensile property of titanium matrix composites was caused by load transfer from the titanium matrix to the reinforcement and by grain refinement of titanium matrix and reinforcements.

In-situ EQCM Study on Growth of Polypyrrole Films Using Gold Electrodes Modified with Self-Assembled Monolayers in an Aqueous Solution (자기 집합 단분자막 개질 금 전극을 이용한 수용액 중 폴리피를 성장에 관한 In-situ EQCM 연구)

  • Seo, Kyoung--Ja;Jeon, Il-Cheol
    • Journal of the Korean Electrochemical Society
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    • v.5 no.3
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    • pp.143-152
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    • 2002
  • The growth of Polypyrrole film has been investigated during electropolymerization in an aqueous solution on bare and SAM modified gold electrodes by in-situ EQCM and ex-situ AFM. According to the result of cyclic voltammetry measurements, in the case of a bare gold electrode, the electrochemical deposition of polypyrrole were dependent on the limiting oxidative potential, but not on scan numbers. When the limiting potential higher than 0.8 V was applied on the electrode, the amount of polypyrrole deposited on a gold electrode was rapidly increased and the abnormal mass change attributed to the rearrangement of polypyrrole films was observed as the scan number increased. The polypyrrole film Prepared on electrodes modified with 1-dodecanethiol SAM or thiophene SAM grew 3-dimensionally with the rearrangement of film. However, in the case of BPUS SAM, 2-dimensional layer-by-layer growth of film was observed without the rearrangement of film. AFM images showed films with chain-shaped and/ or donut-shaped polymers when grown rapidly and a wrinkled film at the steady state condition.

Estimation of Machinability of Lead Brass Based on In-Situ Observation in Scanning Electron Microscope (전자현미경 In-Situ 관찰방법을 이용한 황동의 절삭성평가)

  • Jung, Seung-Boo;Lim, Ok-Dong;An, Seong-Uk
    • Applied Microscopy
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    • v.24 no.3
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    • pp.87-93
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    • 1994
  • In order to elucidate the machinability of lead brass, orthogonal machining experiment was conducted in SEM(Scanning Electron Microscope) equipped with a micro-machining device at a cutting speed of $7{\mu}m/s$ for brass containing 0.2 to 3wt% Pb. The microfactors (i.e., shear angle, contact length between chip and tool) were determined by in-situ observations. Machinability of brass containing lead is discussed in terms of the microfactors and the cutting resistant force tested by lathe cutting. The dynamic behavior of the chip formation of lead brass during the machining process was examined: The chips of lead brass form as a shear angle type. The shear angle increases with the content of lead in (6:4) brass. The pronounced effect of lead on the contact length between chip and tool was observed above 1% Pb. The cutting resistant force tested by lathe decreases remarkably with the lead content in brass. The observed microfactors are in close relation to the tested resistant force in macromachining.

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A Study on Mechanical Properties and Fracture Behaviors of In-situ Liquid Mixing Processed FeAl/TiC Intermetallic Matrix Composite (In-situ Liquid Mixing 방법으로 제조된 FeAl/TiC 금속간화합물 복합재료의 기계적 특성과 파괴양상에 관한 연구)

  • Chung, Euihoon;Park, Ikmin;Park, Yongho
    • Korean Journal of Metals and Materials
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    • v.48 no.7
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    • pp.683-689
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    • 2010
  • In this study, FeAl based intermetallic matrix composites reinforced with in-situ synthesized TiC particles were fabricated by an in-situ liquid mixing process. The microstructures, mechanical properties and fracture behaviors of the in-situ liquid mixing processed composite were investigated and compared with the vacuum suction casting processed composite. The results showed that the in-situ formed TiC particles exhibited fine and uniform dispersion in the liquid mixing processed composite, while significant grain boundary clustering and coarsening of TiC particles were obtained by the vacuum suction process. It was also shown in both types of composites that the hardness and bending strength were increased with the increase of the TiC volume fractions. Through the study of fractography in the bending test, it was considered that the TiC particles prohibited brittle intergranular fracture of FeAl intermetallic matrix by crack deflections. Because of the uniformly distributed fine TiC particles, the bending strength of the liquid mixing processed composite was superior to that of the casting processed composite.

Structural and Morphological Changes of Co Nanoparticles and Au-10at.%Pd Thin Film Studied by in Situ Heating in a Transmission Electron Microscope

  • Ji, Yoon-Beom;Park, Hyun Soon
    • Applied Microscopy
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    • v.47 no.3
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    • pp.208-213
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    • 2017
  • The microstructural changes in Co nanoparticles and an Au-10at.%Pd thin film have been investigated using an in situ heating holder with a micro-electro-mechanical system (MEMS). In Co nanoparticles, two phases (face-centered cubic and hexagonal close-packed crystal structures) were found to coexist at room temperature and microstructures at temperatures, higher than $1,000^{\circ}C$, were observed with a quick response time and significant stability. The actual temperature of each specimen was directly estimated from the changes in the lattice spacing (Bragg-peak separation). For the Au-10at.%Pd thin film, at a set temperature of $680^{\circ}C$, the actual temperature of the sample was estimated to be $1,020^{\circ}C{\pm}123^{\circ}C$. Note that the specimen temperature should be carefully evaluated because of the undesired effects, i.e., the temperature non-uniformity due to the sample design of the MEMS chip, and distortion due to thermal expansion.