• Journal of the Korean Ceramic Society
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• v.26 no.2
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• pp.242-248
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• 1989

The powder properties and sinterability of ZrO2-8m/o Y2O3 prepared by coprecipitation were investigated. The specific surface area and the total pore volume were increased with increasing pH of sediment and using of ethyl alcohol for washing. The powders of prepared by freeze drying method were showed the smallest particle size and lowest agglomerate rate, and the powders obtained from spray drying method were showed porous structure. At 130$0^{\circ}C$, their relative density were 94-96%, so these sintered bodies have revealed high sinterability in spite of low sintering temperature.

• Journal of the Korean Ceramic Society
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• v.20 no.1
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• pp.55-62
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• 1983

the preliminary work on the prepartion of fine hydroxyapatite powder and the synthesis of dense hydroxyapatite ceramic from the powder were investigated for the development of artificial bone and tooth materials for implants. The effects of the process variables such as compositions of the raw materials the initial pH of the solutions and sintering temperature on the physical properties were investigated in order to determine the optimum conditions for the fabrication of tooth implant material. As the initial pH of the solutions was increased in the range of 10-11.6 the initial particle size of precipitates was decreased thus the sinterability of precipitates was improved. It was found that the composition of calcium rich of 1.75 in Ca/P mole ratio exhibited better sinterability and mechanical strength of the apatite ceramics for example the highest value of Vicker's hardness obtained from the compositions of 1.75 in Ca/P mole ratio was 764±30 Kg/mm2 compared to the maximum value of 600 kg/mm2 obtained from the compositions of 1.67 in Ca/P mole ratio.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.49-49
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• 1999

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.10a
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• pp.29-29
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• 1997

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.269.2-269
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• 2001

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.30.2-30.2
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• 2000

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.222.2-222
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• 2001

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.05a
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• pp.21-21
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• 1996

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.208-209
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• 2006

Sinterability and microwave dielectric properties of the $Zr1-x(Zn_{1/3}Nb_{2/3})xTiO_4$(x=4, 6) system ceramics have been investigated as functions of zinc-borosilicate(ZBS) glass contents and amount of $Zn_{1/3}Nb_{2/3}O_2$ substitution with a view to applying the composition to LTCC technology. The addition of 25 wt% ZBS glass ensured successful sintering below $925^{\circ}C$. With increasing ZBS glass and $Zn_{1/3}Nb_{2/3}O_2$ contents increased dielectric constant and sinterability but addition ZBS glass decreased the quality factor significantly due to the formation of an excessive liquid and second phases. The sintered $Zr4(Zn_{1/3}Nb_{2/3})6TiO_4$ system ceramics at $925^{\circ}C$ with 25 wt% ZBS glass demonstrated 27.7 in dielectric constant (${\varepsilon}_r$), 3,850 m quality factor($Q{\times}f_0$), and +6 ppm/$^{\circ}C$ in temperature coefficient of resonant frequency($\tau_f$).

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.231-237
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• 1996

Defect equilibrium equations were modelled, and the relations of P $o_2$, venus x were derived using the mass action law. The dominant defect species active in a specified region were determined by fitting the curve of experimental data to the calculated curve of log P $o_2$, versus log x for each theoretical model. The calculated curve for (2:1:2) and (Er')$^{x}$ in the hyperstoichiometric $U_{1-y}$E $r_{y}$ $O_{2＋x}$ and that for (2Er'quot;)$^{x}$ $_{dec}$ in the hypostoichiometric $U_{1-y}$E $r_{y}$ $O_{2－x}$ are in good agreement with the present experimental results. The sintering behavior of Er-doped U $O_2$ is observed with erbium content in oxidizing and reducing atmospheres. For sintering in oxidizing atmosphere, sintered density decreases as increasing y in $U_{1-y}$E $r_{y}$ $O_{2＋x}$. However, in hydrogen atmosphere, sintered density decreases as increasing y at lower erbium content but the density increases again above y=0.10. In oxidizing sintering conditions, the formation of (Er'U')$^{x}$ clusters hinders the diffusion of cations, and hence the sinterability of Er-doped U $O_2$ decreases. In reducing atmosphere of Er-doped U $O_2$ for higher Er concent, the oxygen vacancies make (Er')$^{x}$ cluster decompose by charge compensation and the concentration of mobile cations increases, thereby improving the sinterability.ntration of mobile cations increases, thereby improving the sinterability.ability.