• 한국진공학회지
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• 제12권S1호
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• pp.21-27
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• 2003

Micro-arc discharge oxidation (MDO) is a cost-effective plasma electrolytic process which can be used to improve the wear and corrosion resistance of Al-alloy parts by forming a alumina coating on the component surface. However, the MDO coated Al-alloy components often exhibit relatively high friction coefficients and low wear resistance fitted with many counterface materials, additionally, the pitting corrosion for the MDO coated AI-alloy components, especially for a thinner alumina coating, often occurs in atmosphere circumstance due to the porous alumina coats. Therefore, a duplex treatment, combining a MDO coated ahumina thin layer with a TiN coating, prepared by magnetron sputtering (MS), has been investigated. The Vicker's microhardness, pin-on-disc, electrochemical measurement, salt spray, XRD and SEM tests were used to characterize and analyze the treated samples. The work demonstrates that the MDO/MS coated samples have a combination of a very low friction coefficient and good wear resistance as well as corrosion since the micro-holes on alumina coating are partly or fully covered by TiN material.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.359-361
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• 2003

Nano-porous alumina was investigated as a protecting layer in an AC Plasma Display Panel. A 2 ${\mu}m$ thick nano-porous $Al_2O_3$ layer inserted with MgO was formed on the dielectric layer instead of the conventional 500 nm-thick MgO thin film. Both nano-porous $Al_2O_3$layer and inserted MgO were prepared by wet process. The luminance and luminous efficiency of 3-inch test panel adopting nano-porous $Al_2O_3$ was higher than that of the conventional PDP.

• 공업화학
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• 제20권6호
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• pp.586-592
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• 2009

나노 크기의 배향성을 갖는 구조물의 제작은 자연에 존재하는 여러 가지 형상의 모방을 가능하게 한다. 고분자는 가격이 매우 저렴하며 합성과 가공 그리고 그 구조가 잘 알려져 있는 장점을 갖고 있어 필름(film)의 표면에 이러한 나노 구조물을 제작하고 나노 구조의 특성을 발현하는데 손쉽게 활용할 수 있는 재료이다. 나노 구조물을 제작하는 방법 중 양극산화를 통하여 제작한 다공성 알루미나 템플레이트(porous alumina template)는 매우 규칙적으로 정렬되어 있고 제어하는 공정이 비교적 쉽고 경제적이기 때문에 이를 이용한 연구가 매우 활발하게 진행되고 있다. 본 총설에서는 양극산화 알루미나 템플레이트의 제작과 이를 이용한 나노 구조 고분자 필름의 제작을 설명하고 이러한 나노 구조 필름의 응용범위 및 응용에 필요한 특성에 대하여 기술하였다.

• 신재생에너지
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• 제1권1호
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• pp.64-71
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• 2005

The stability of alumina-coated NiO cathodes was studied in $Li_{0.62}/K_{0.38}$ molten carbonate electrolyte. Alumina was effectively coated on the porous Ni plate using galvanostatic pulse plating method. The deposition mechanism of alumina was governed by the concentration of hydroixde ions near the working electrode, which was controlled by the temperature of bath solution. Alumina-coated NiO cathodes were formed to $A1_2O_3-NiO$ solid solution by the oxidation process and their Ni solubilities were were than that of NiO up to the immersion time of 100h. However, their Ni solubilities increased and were similar to that of the bare NiO cathode after 100h. It was because aluminum into the solid solution was segregated to $\alpha-LiAlO_2$ on the NiO and its Product did not Play a role of the Physical barrier against NiO dissolution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.375-375
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• 2007

In the conventional crystallization method, thepoly-Si TFTs show poor device-to-device uniformity because of the random location of the grain boundaries. However, our new crystallization method introduced in this paper employed substrate-embedded seeds on the highly ordered anodic alumina template to control both the location of seeds and the number of grain boundaries intentionally. In the process of excimer laser crystallization (ELC), a-Si film deposited on the anodic alumina by low pressure chemical vapor deposition (LPCVD) is transformed into fine poly-Si grains by explosive crystallization (XC) prior to primary melting. At the higher energy density, the film is nearly completely melted and laterally grown by super lateral growth (SLG) from remained small part of the fine poly-Si grains as seeds at the Si/anodic alumina interface. Resultant grain boundaries have almost linear functions of the number of seeds in concavities of anodic alumina which have a constant spacing. It reveals the uniformity of. device can be enhanced prominently by controlling location and size of pores which contains fine poly~Si seeds under artificial anodizing condition.

• 멤브레인
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• 제15권2호
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• pp.105-113
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• 2005

표면 개질한 다공성 금속 지지체에 초음파 분무 열분해법을 이용하여 silica막을 합성하고, 고온 기체 선택 투과 분리 특성을 조사하였다. Tetraethyl orthosilicate (TEOS)를 전구체로 하여 지지체 세공을 통한 감압 진공을 하면서 873K에서 표면에 defect 없이 균일한 양질의 silica막이 형성되었다. 투과 온도 523 K에서 silica막의 수th/질소 및 수증기/메탄을 분리 계수가 각각 17 및 16 정도의 우수한 선택 투과 성능을 나타냈다. 다공성 금속 지지체의 불균일한 기공에 silica 분체 및 $\gamma-alumina$층을 중간층으로 도입하고, 그 위에 열분해법에 의한 silica를 합성한 결과, Knudsen 확산에 의한 투과 영역의 세공이 완전히 제거되어 높은 수소 및 수증기 선택성을 가지는 복합 막이 형성되었다.

• 한국세라믹학회지
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• 제39권12호
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• pp.1153-1157
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• 2002

입도가 다른 두 가지 고순도 ${\alpha}-Al_2O_3$ 분말을 이용하여 slip casting법과 담금코팅(dip coating)법으로 다공질 알루미나 지지체와 중간층을 각각 제조하였으며, 그 위에 분리막인 산화티탄($Tio_2$)층을 Ti-naphthenate용액으로 screen printing한 후 열분해시켜 형성시킴으로써, 3층 구조의 비대칭성 세라믹 분리막을 제조하였다. 알루미나 지지체의 곡강도, 기공율 및 평균 기공크기는 각각 231 Kg/$cm^2$, 30.26%, 0.19 ${mu}m$였으며, 중간층은 두께가 약 30 ${mu}m$, 평균 기공크기가 0.063 ${mu}m$였다. 또한 최상층 $Tio_2$ 분리막은 그 두께가 약 0.5 ${mu}m$였으며 평균 약 20 nm 정도의 미세 기공들이 매우 균일하게 형성되어 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.18.2-18.2
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• 2009

Ceramics have some properties that are unmatched by other kind of materials like metals or polymers. The ability of high thermal and chemical resistance and in case of being superior in specific mechanical properties makes the ceramic materials suitable for arange of applications. The microstructure and morphology of a material arguably permit the use of many advanced application otherwise difficult to achieve.Porous structures have some important applications in biomedical and environmental field. For human hard tissue reconstruction and augmentation procedure suitable biomaterials are used with a desirable porosity. A range of porous bioceramics were fabricated with tailored design to meet the demand of specific applications. Channeled and interconnected porosity was introduced in alumina, zirconia, and hydroxyapatite or tri calcium phosphate ceramics by different methods like multi-pass extrusion process, bubble formation in viscous slurry,slurry dripping in immiscible liquid, sponge replica method etc. The detailed microstructural and morphological investigations were carried out to establish the unique features of each method and the developed systems. For environmental filters the porous structures were also very important. We investigated a range of channeled and randomly porous silicon based ceramic composites to enhance the material stability and filtration efficiency by taking advantage of the material chemistry of the element. Detailed microstructural and mechanical characterizations were carried out for the fabricated porous filtration systems.

• 멤브레인
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• 제10권3호
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• pp.121-129
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• 2000

높은 선택도와 투과도를 가진 분리막이 요구되지만 선택도가 높은 막은 투과도가 낮은 것이 일반적이다. 본 연구에서는 적절한 선택도를 유지하면서 높은 투과도를 갖는 분리막을 제조하기 위하여 다공성 알루미나막을 실란커플링제로 코팅하였다. 코팅된막에 대한 물의 접촉각은 90$^{\circ}$ 이상이었으며, 큰 소수성을 가짐을 의미하기 때문에 에탄올, 이소프로판올, 부탄을 수용액의 농축을 위한 증기투과실험을 수행하였다. 공급액중의 알코을 농도가 증가함에 따라 투과도가 증가하였으며, 이는 물에 비하여 코팅된 막에 대한 에탄올, 이소프로판올, 부탄올의 친화도가 크기 때문으로 판단된다. 코팅된 알루미나막의 투과도는 고분자막의 투과도에 비하여 20~1000배로 크게 나타났다.

• 한국전기전자재료학회논문지
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• 제30권11호
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• pp.683-687
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• 2017

We investigated the structure of an ultra-thin insulating board with low thermal conductivity along z-axis, which was based on the idea of void layers created during the glass infiltration process for the zero-shrinkage low-temperature co-fired ceramic (LTCC) technology. An alumina and four glass powders were chosen and prepared as green sheets by the tape casting method. After comparison of the four glass powders, bismuth glass was selected for the experiment. Since there is no notable reactivity between alumina and bismuth glass, alumina was selected as the supporting additive in glass layers. With 2.5 vol% of alumina powder, glass green sheets were prepared and stacked alternately with alumina green sheet to form the 'alumina/glass (including alumina additive)/alumina' structure. The stacked green sheets were sintered into an insulating substrate. Scanning electron microscopy revealed that the additive alumina formed supporting bridges in void layers. The depth and number of the stacking layers were varied to examine the insulating property. The lowest thermal conductivity obtained was 0.23 W/mK with a $500-{\mu}m-thick$ substrate.