• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 춘계학술발표회 논문집
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• pp.319-319
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• 2012

수용액에서 양극산화법을 이용하여 티타늄 표면에 $TiO_2$ 나노튜브를 형성시켰고, XRD 및 전자현미경을 통해 열처리를 한 $TiO_2$ 나노튜브 소재표면, 계면구조를 관찰하였으며, 이는 향후 나노튜브의 결정구조를 제어할 수 있는 자료로 활용 될 것으로 기대된다.

• 한국분말재료학회지
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• 제19권3호
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• pp.196-203
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• 2012

$TiO_2$ was successfully formed on a Ti specimen by MAO (Micro-Arc-Oxidation) method treated in $Na_3PO_4$ electrolyte. This study deals with the influence of voltage and working time on the change of surface microstructure and phase composition. Voltage affected the forming rate of the oxidized layer and surface microstructure where, a low voltage led to a high surface roughness, more holes and a thin oxidized layer. On the other hand, a high voltage led to more dense surface structure, wider surface holes, a thick layer and fewer holes. Higher voltage increases photocatalytic activity because of better crystallization of the oxidized layer and good phase composition with anatase and rutile $TiO_2$, which is able to effectively separate excited electrons and holes at the surface.

• 한국재료학회지
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• 제20권1호
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• pp.12-18
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• 2010

$CuInSe_2$ (CIS) thin films were electrodeposited on Mo-coated glass substrates in acidic solutions containing $Cu^{2+}$, $In^{3+}$, and $Se^{4+}$ ions, depending on deposition parameters such as deposition potential (-0.4 to -0.8 V[SCE]) and pH (1.7 to 1.9). The influences of PH and deposition potential on the atomic composition of Cu, In, and Se in the deposited films were observed. The best chemical composition, approaching 1:1:2 atomic ratio for the elements, was achieved at -0.5 V (SCE) and pH 1.8. The as-deposited films showed low crystallinity and were annealed at 300 to $500^{\circ}C$ for 30 min to improve crystallization. The surface morphologies, microstructures, and crystallographic structures of the annealed films as well as the as-deposited films were analyzed with AFM, SEM, and XRD. The defects of spherical particles appeared on the surfaces of CIS thin films in the as-deposited state and decreased in size and number with increasing annealing temperatures. Additionally, the crystallization to chalcopyrite structure and surface roughness (Ra) of the as-deposited thin films were improved with the annealing process.

• 한국결정성장학회지
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• 제12권5호
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• pp.229-233
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• 2002

유기화학적 방법인 착체중합법을 이용하여 나노사이즈의 ZnO 분말을 저온에서 합성하였다. 고분자 전구체는 Zn nitrate hexahydrate를 사용하였고, chelating agent로서 citric acid를 reaction medium으로서 ethylene glycol을 혼합하여 제조하였다. 고분자 전구체를 300~$700^{\circ}C$의 온도범위에서 3시간 동안 하소하였으며, 열분해와 결정화 과정을 TG-DTA, FI-IR과 XRD 등을 이용하여 분석하였다. 결정화 온도에 따른 입자의 형상이나 크기를 SEM, TEM의 분석 및 Scherrer's equation을 이용한 계산을 통하여 관찰 및 비교를 하였다. ZnO의 결정화는 $300^{\circ}C$부터 시작되었고, $400^{\circ}C$에서 완전히 합성되었음을 알 수 있었다. 400~$700^{\circ}C$에서 하소된 ZnO 입자들은 대부분 둥근 형태로 균일하게 분포되었으며, $400^{\circ}C$에서 하소된 분말의 평균입도는 약 30~40nm를 보였다. 일반적으로 온도의 상승에 따라 입경이 증가되는 일반적인 경향이 관찰되었다.

• 한국세라믹학회지
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• 제40권2호
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• pp.132-138
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• 2003

출발물질의 종류와 몰비 혼합 방법, 숙성, 결정화 온도와 결정화 시간 등 제올라이트 입자를 합성하는 조건이 FAU 형 제올라이트의 입자크기에 미치는 영향을 연구하였다. 동일한 출발물질이라도 혼합 경로에 따라 생성물의 결정상이 달랐다. 일반적으로 숙성과정을 거친 경우, 특히 숙성온도가 낮은 쪽이 입자 크기가 작았다. 2단계의 혼합겔 제조 방법을 거치는 경우 결정화 기간은 크게 단축되고 입자 크기도 작아졌으나. 1단계에서 제조된 2종의 혼합겔을 모두 숙성하지 않는 경우에는 결정화 시간은 단축되지만, 입자크기는 작아지지 않았다. 액상규산나트륨과 알루민산나트륨, 수산화나트륨을 출발물질로 하여. 저농도와 고농도의 혼합겔을 1차 제조하고, 이 혼합겔을 각각 숙성하고 다시 혼합하여 숙성하는 방법으로 결정화 시간을 단축하고 평균입경 0.4$\mu$m. 비표면적 838 $m^2$/g의 우수한 특성을 가지는 FAU혈 제올라이트를 합성하였다.

• 한국세라믹학회지
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• 제25권4호
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• pp.373-379
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• 1988

$\alpha$-Al2O3-15m/o ZrO2 powder was prepared by a sol-gel method from boehmite and zirconium acetate. The transformation temperature of boehmite to $\alpha$-Al2O3 in the system Al2O3-ZrO2 was increased due to the coupled crystallization. On the other hand, the transformation temperature from boehmite to $\alpha$-Al2O3-15m/o ZrO2 could be prepared at 110$0^{\circ}C$ for 100min. The specific surface area of the product of $\alpha$-Al2O3-15m/o ZrO2 was 13.2$m^2$/g.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.818-821
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• 2003

Sn-doped $In_{2}O_{3}$ (ITO) thin film is one of the materials widely on research not only in the academic fields but also in industrial fields because of their transparency, high conductivity and good adhesion characteristics on substrate. ITO thin films are usually preferred oriented to one of the (222), (400), and (440) planes during crystallization process, which is dependent on processing variables. The preferred orientation affects electrical, optical and etching properties of the films. In this study, thin films of preferred oriented in different orientation were fabricated by controlling processing variables. The crystallization behavior, grain size, surface roughness, transparency and electrical properties of the thin films in different orientation were examined.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.273-276
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• 2005

Packing characteristics of amorphous alloy particles were investigated by scanning electron microscopy, compositional analysis, micro-hardness test and finite element method (FEM). Electroless Ni-plating was made on the surface of the Cu-based amorphous particles before consolidation in ambient atmosphere at an intermediate region of glass transition and crystallization temperatures $(T_g\;and\;T_x)$. Some parts of the Ni-layer in the interfaces of the consolidated particles disappeared, while some of them still remained without appreciable change in compositions. No cracks or fractures were found in the particles, which may occur at low temperatures below or near $T_g$ as anticipated by the FEM analysis. Crystallization and change in hardness were not observed after consolidation.

• 한국세라믹학회지
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• 제29권10호
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• pp.815-821
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• 1992

The batches having excess SiO2 to tetrasilicic mica KMg2.5 (Si4O10)F2 were melted at 1450℃. The fabricated samples were heat-treated for the nucleation and the crystallization. The crystallized samples were investigated on several properties. The tetrasilicic mica composition with excess 10 wt% SiO2 was successful both in glassifying and in crystallizing. The optimum temperatures for the nucleation and the crystallization were 680℃ and 1000-1100℃, respectively. The mica and the cristobalite crystallines were identified after heat-treatment. The properties of the samples processed appropriately were as follows, bulk density 2.64g/㎤, thermal expansion coefficient ∼80×10-7/℃, Vicker's hardness ∼105 Kgf/㎟, bending strength ∼666Kgf/㎟, dielectric constant ∼11.1, tan δ 2.5%, volume resistivity 2.35×107∼1.3×1011{{{{ OMEGA }}cm, surface roughness 6.984㎛.

• Journal of Electrochemical Science and Technology
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• 제9권1호
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• pp.1-8
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• 2018

The effect of mixing ratio on the corrosion protection of carbon steel coated by a film composed of poly(vinylidene) fluoride (PVDF) and poly(methyl methacrylate) (PMMA) was examined using electrochemical impedance spectroscopy. Surface crystallization behavior and thermal properties of the PVDF/PMMA coated carbon steel were evaluated using polarized optical microscopy and differential scanning calorimetry, respectively. A Maltese cross-pattern spherulite crystal was observed in the PVDF/PMMA coating film, which became more apparent with increasing PVDF content. The highest corrosion protection performance was achieved with 60 wt.% PVDF-coated carbon steel, and delamination and corrosion reactions were observed for 20 wt.% PVDF-coated carbon steel. Further, corrosion protection performance with an amorphous/crystal mixture (PVDF/PMMA, 60/40 (w/w)) was better than those observed in the amorphous domain and the perfect-crystal domain of the PVDF/PMMA blended coating system.