• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.3
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• pp.284-293
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• 1994

The various methods of preparation for the porous hydroxyapatite ceramics using naphthalene, $H_20_2$ and chlorinated paraffine with $H_20_2$ were investigated. And then the prepared orous hydroxyapatite ceramics were characterized by XRD, SEM, FT-IR and the apparent porosity. The pore size of porous hydroxyapatite ceramics was controlled by the content and size of naphthalene granular. It was found that the porosity of it was increased with the amount of naphthalene, but the bending strength was decreased. The application of hydrogen peroxide produced porous materials like a sponge tissue, but the porosity and the shape of sintered body were hardly controlled. In the case of using chlorinated paraffine with the simultaneous addition of hydrogen peroxide, the sponge tissue was obtained and also could be controlled from 50 up to about 65% porosity of it.

• Journal of the Korean Ceramic Society
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• v.26 no.6
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• pp.771-782
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• 1989

Synthesis of $\beta$-Sialon powder was attempted with carbothermal reduction of porous glass. The porous glass was prepared by heat and hydrothermal treatments of 9.32 Li2O.46.5B2O3.37.2SiO2.6.98Al2O3 glass. Carbon pyrolyzed from propane gas was deposited on the porous glass, thereafter activated carbon was added as reducing agents. The synthesized $\beta$-Sialon powder was pressureless sintered at 175$0^{\circ}C$ for 1hr in N2 atmosphere. The characterization of the $\beta$-Sialon powder was performed with XRD, BET, SEM and particle size analysis. The sinterability and mechanical properties of the sintered bodies were investigated in terms of bulk density, M.O.R., fracture toughness, morphology of microstructure and etc. The reduction effect of deposited carbon was better than that of activated carbon mechanically added. The formation of SiC was precominant over that of Si2ON2 and $\beta$-Sialon owing to low partial pressure of N2 inside the pore, wehreas on the surface of porous glass the formation of Si2ON2 and $\beta$-Sialon were predominant. Thereafter, SiC reduced unreacted glass to be $\beta$-Sialon. Single phase of $\beta$-Sialon(Z=1.92) was obtained from PGA porous glass having the largest pore radius by the simultaneous reduction and nitridation method at 145$0^{\circ}C$ for 5hrs. The bulk density, M.O.R., and KIC of the sitered body are 3.17g/cc, 434.4MPa and 4.1MPa.m1/2, respectively.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.67-71
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• 2013

Porous $Al_2O_3$ dispersed with nano-sized Cu was fabricated by freeze-drying process and solution chemistry method using Cu-nitrate. To prepare porous $Al_2O_3$, camphene was used as the sublimable vehicle. Camphene slurries with $Al_2O_3$ content of 10 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled to $-25^{\circ}C$ while unidirectionally controlling the growth direction of the camphene. Pores were subsequently generated by sublimation of the camphene during drying in air for 48 h. The green body was sintered in a furnace at $1400^{\circ}C$ for 1 h. Cu particles were dispersed in porous $Al_2O_3$ by calcination and hydrogen reduction of Cu-nitrate. The sintered samples showed large pores with sizes of about $150{\mu}m$; these pores were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores due to the traces of camphene left between the concentrated $Al_2O_3$ particles on the internal wall. EDS analysis revealed that the Cu particles were mainly dispersed on the surfaces of the large pores. These results strongly suggest that porous $Al_2O_3$ with Cu dispersion can be successfully fabricated by freeze-drying and solution chemistry routes.

• Journal of Industrial Technology
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• v.4
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• pp.43-46
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• 1984

In process of water removing safely from plastic clay, an electric field applied to a wet, porous solid such as day usually causes the rapid dehydration. The water-bearing positive ions move to negative electrode under the d. c. electrical stress or field. Therefore application of electro-osmosis to wet clay could include drying thick and large-scale ceramic body quickly and evenly. The d. c. power supply unit to 60 volts is necessary for safe practice. Also wider contact area and shorter distance between electrodes accelerate effectively the removal of water.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.891-898
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• 1990

This study deals with the porous sintered body which is obtained by blending solid naphthalene with fine particles of Hwasun flint clay. Apparent porosity is increased, and bulk density, thermal conductivity, strength and thermal expansion are decreased according to the additiion of naphthalene. Pore shape of sintered body showed elliptical form and median size and capilary percentage are increased by adding more naphthalene.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.04a
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• pp.35-35
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• 2001

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.05a
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• pp.38-38
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• 2001

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.69.2-69
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• 2003

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.18-19
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• 2000

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1999.10a
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• pp.6-7
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• 1999