• 한국세라믹학회지
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• 제43권6호
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• pp.351-357
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• 2006

The fabrication process of the honeycomb filter was investigated using synthesized cordierite with the addition of pore former and extrusion additives (either organic matter or graphite). Also, the effect of additives on the resultant properties of honeycomb filter such as porosity, thermal expansion coefficient and mechanical strength were investigated. With increasing the organic matter up to 10 wt%, porosity was increased but compressive strength was decreased. With increasing the graphite content, however, both porosity and compressive strength were increased. The specimen with an optimum processing condition (C-17A30G, sintering at $1150^{\circ}C$) was demonstrated 59% in porosity, 69 MPa in compressive strength, and $2.4{\times}10^{-6}/^{\circ}C\;(25{\sim}1000^{\circ}C$) in thermal expansion coefficient, which physical properties are appropriate for the honeycomb filter applications.

• 한국분말재료학회지
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• 제17권1호
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• pp.44-51
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• 2010

The rheological behavior of a cordierite honeycomb extrusion paste was investigated by measuring torque values in a Brabender plastograph. The extrusion pastes were formulated using binder (methy cellulose, MC), solvent (water), plasticizer (ploy ethylene glycol, PEG) and lubricants (oleic acid, OA). The mixing sequence and optimum organic binder, at least for homogeneous mixed state, can be determined from the rheological point of view. 3%MC-30%$H_2O$-1.5%PEG-1.0%OA with respect to the cordierite powder was chosen as a binder composition for the extrusion process of cordierite powder.

• 한국결정성장학회지
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• 제31권3호
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• pp.116-126
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• 2021

코디어라이트(Mg₂Al₄Si₅O₁₈) 하니컴 세라믹스의 대표적 응용분야는 자동차 배기가스 정화용 필터(diesel particulate filter(DPF))이다. 천연광물, 조공제, 유기바인더를 혼합한 슬러리를 압출하여 DPF용 하니컴 코디어라이트를 성형한 후 980~1450℃ 범위에서 소결하였다. 소결온도에 따른 결정상(indialite, cordierite, cristobalite, alumina, spinel, mullite, pro-enstatite)의 형성과정을 XRD Rietveld 정밀화법을 이용하여 정량분석 하였다. 동시에, 세라믹 에칭(etching) 방법으로 소결 시료 표면의 비정질상을 제거한 후 SEM/EDS법을 사용하여 결정상들의 형상과 조성을 확인하였다. 이들 결과로부터 DPF 하니컴에서 결정상 형성 과정을 명확히 밝힐 수 있었다. 또한, DPF 하니컴의 소결온도에 따른 열팽창계수(linear coefficient of thermal expansion, CTE) 변화를 분석하였고, 결정상의 정량분석결과를 바탕으로 계산된 CTE와 비교하였다. 소결된 DPF 하니컴 내의 결정상들이 CTE 특성에 미치는 영향을 고찰하였다.

• 한국세라믹학회지
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• 제53권2호
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• pp.227-233
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• 2016

In order to make a highly ordered three-dimensional porous structure of titania ceramics, porogen beads of PS [Polystyrene] and PMMA [poly(methylmetacrylate)] were prepared by emulsion polymerization using styrene monomer and methyl methacrylate monomer, respectively. The uniform beads of PS or PMMA latex were closely packed by centrifugation as a porogen template for the infiltration of titanium butoxide solution. The mixed compound of PS or PMMA with titanium butoxide was dried and the dry compacts were calcined at $450^{\circ}C-750^{\circ}C$ according to the firing schedule to prepare micro- and meso- structures of polycrystalline titania with monodispersed porosity. Inorganic frameworks composed of $TiO_2$ were formed and showed a three Dimensionally Ordered Microstructure [3DOM] of $TiO_2$ ceramics. The pulverized particles of the $TiO_2$ ceramic skeleton were characterized using XRD analysis. A monodispersed crystalline micro-structure with micro/meso porosity was observed by FE-SEM with EDX analysis. The 3DOM $TiO_2$ skeleton showed opalescent color tuning according to the direction of light.