• 한국세라믹학회지
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• 제46권1호
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• pp.108-115
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• 2009

In this study, a novel-processing route for producing microcellular zirconia ceramics has been developed. The proposed strategy for making the microcellular zirconia ceramics involves hollow microsphere as a pore former which has extremely low density of $0.025\;g/cm^3$. Effects of hollow microsphere content and sintering temperature on microstructure, porosity, pore distribution, and compressive strength were investigated in the processing of microcellular zirconia ceramics. By controlling the content of hollow microsphere, it was possible to make the porous zirconia ceramics with porosities ranging from 45% to 75%. Typical compressive strength value of microcellular zirconia ceramics with ${\sim}65%$ porosity was over 50 MPa. By adjusting the mixing ratio of large and small zirconia powders, it was possible to control the pore structure from close to open pores.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.101-102
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• 2006

Processing techniques for producing microcellular silicon carbide, mullite, and cordierite ceramics have been developed by a reaction method that incorporates a polysiloxane and reactive fillers. The techniques developed in this study offer substantial flexibility for producing microcellular ceramics whereby cell size, cell density, degree of interconnectivity, composition, and porosity can all be effectively controlled. It is demonstrated that the adjustment of filler composition enables the possibility of tailoring the composition and properties of the microcellular ceramics. The present results suggest that the proposed novel processing techniques are suitable for the manufacture of microcellular ceramics with high morphological uniformity.

• 한국분말재료학회지
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• 제18권6호
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• pp.502-509
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• 2011

In this study, a novel-processing route for fabricating microcellular zirconia ceramics has been developed. The proposed strategy for making the microcellula zirconia ceramics involved hollow microspheres as pore former. Compared to conventional dense microspheres pore former, well-defined pore structured zirconia ceramics were successfully fabricated. Effects of hollow microsphere content and sintering temperature on microstructure, porosity, pore distribution, and strength were investigated in the processing of microcellular zirconia ceramics.

• 한국세라믹학회지
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• 제44권5호
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• pp.184-189
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• 2007

In this study, a novel-processing route for producing microcellular cordierite ceramics has been developed. The proposed strategy for making the microcellular cordierite ceramics involves three steps: (i) fabricating ceramic-filled preceramic foams by heating a mixture of polysiloxane, expandable microspheres, talc, and alumina in a mold, (ii) cross-linking the foamed body, and (iii) transforming the body into microcellular cordierite ceramics by sintering. Cu jig was used for near net shaping in the foaming step. The experimental variables such as the shape of foaming jig and the content of expendable microsphere were investigated. By controlling the content of expendable microsphere, it was possible to make the porous cordierite ceramics with cell density of ${\sim}1.0{\times}10^9\;cells/cm^3$.

• 한국세라믹학회지
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• 제48권5호
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• pp.404-411
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• 2011

The humidity controlling ceramic materials was developed by applying the phenomena of dew condensation in the capillary. It is said that the humidity range which human feels comfortable is from 40 to 70% in relative humidity. In this study, the ceramic tile using natural soils such as diatomite for interior wall was investigated. In particular, we had introduced novel processing routes for fabricating microcellular ceramics tile using hollow microsphere as a pore former. The microcellular pores in the humidity controlling ceramic materials showed the superior properties such as light-weight, heat insulation. The cell density was ${\sim}1.0{\times}10^9$ cells/$cm^3$ and density of sample was 0.65 g/$cm^3$ in the case of 1.71 wt% hollow microsphere content. Also, it is observed that the BET surface area and the pore volume of the sintered diatomite tile have the values of 40.92 $m^2$/g and 0.173 $cm^3$/g.

• 한국세라믹학회지
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• 제49권6호
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• pp.566-574
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• 2012

Porous zirconia ceramics are widely considered to be important due to their unique properties and potential applications. In this paper, we propose a novel approach to produce porous zirconia ceramics. The linear shrinkage of the prepared porous zirconia ceramics could be controlled to 4% by incorporating pre-sintered zirconia granules and hollow polymeric spheres. We also investigated the effect of pre-sintered zirconia granules on the microstructure and the properties, such as the porosity, pore distribution, and bending strength of the porous zirconia ceramics.