• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.82-88
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• 1999

In this study, the formation of mullite phase with mineralizer have been investiagated Hadong Kaolin and boehmite were used as starting materials and also of TiCl4 and MnCl4 aquous solution were used as a mineralizer. In the addition of 3.5% MnO as a mineralizer, mullite single phase could be obtained at 125$0^{\circ}C$ without any other second phases. However in the addition of TiO2 as a mineralizer, mullite single phase is obtained at above 135$0^{\circ}C$. Therefore the formation of mullite is lowered in the case of MnO as a mineralizer than of TiO2. Because it is easy to obtain mullite single phase in the case of MnO addition, all the characteristics improved. The values of bulk density, water absorption and bending strength at room temperature were 2.72g/㎤, 0.27% and 180 MPa, respectively.

• Journal of the Korean Ceramic Society
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• v.45 no.5
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• pp.256-262
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• 2008

$ZnAl_{1-x}\;Cr_xO_4$ solid solutions were synthesized as pink pigments with and without mineralizer. The pigments were examined to optimize color development conditions of temperature and $Cr_2O_3$ contents. The characteristics of synthesized pigments were analyzed by XRD, XPS, FT-IR and UV-vis spectrophotometer. While samples without mineralizer fired at $1300^{\circ}C$, showed $ZnAl_2O_4$ and $ZnCr_2O_4$ spinel in XRD analysis. While samples with mineralizer resulted in $ZnAl_2O_4$. As a results, the pigments show pink color and most effective pink color was obtained at X=0.15 and $1250^{\circ}C$ when mineralizer was used. The chromatic coordinates are $L^*$ 58.61 $a^*$ 24.48, and $b^*$ 9.60.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.743-748
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• 2005

The effect of reaction parameters in the characteristic of $Pb(Zr_{0.52} Ti_{0.48})O_3$ powders by hydrothermal process was investigated in this study. In the preparation of PZT, the types of starting material and concentration of mineralizer on phase fraction and morphology was investigated respectively. Regardless the types of Pb precursor, PZT was able to synthesize ranging from 7 to 20 on KOH concentration and from 13.01 to 13.55 on pH of solution. The particle size of the PZT powders can be controlled by the mineralizer concentration and various types of precursor.

• Journal of the Korean Ceramic Society
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• v.37 no.8
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• pp.739-744
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• 2000

YAG(Y3Al5O12) as host material of YAG:Tb3+ was studied via hydrothermal synthesis of metal hydroxides. We changed the kind of mineralizer, the concentrations and process conditions in hydrothermal synthesis. As a result, we found, acicular YAG powders were obtained by the use of KOH as a mineralizer, the concentration of KOH affected the shape and size of YAG powder. Fine grained YAG were perpared by the use of NH4OH as a mineralizer and the concentration of NH4OH affected crystal phases but did not affect particle size. We could finally get the spherical looking YAG powder at 8 M NH4OH and at 35$0^{\circ}C$ for 12h. The average particle size was about 0.2${\mu}{\textrm}{m}$.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.516-520
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• 2005

Conditions for formation of perovskite Pb(Zr$_{0.52}$Ti$_{0.48}$)O$_{3}$ phase by the hydrothermal synthesis are investigated. Pb(Zr$_{0.52}$ Ti$_{0.48}$)O$_{3}$ ceramics were synthesized by hydrothermal process above 180$^{\circ}C$ for 2 h reaction using 5$\~$30 M KOH solution as a mineralizer. Particle size increases in proportion to the mineralizer concentration. As a result of EOX analysis, PZT powders synthesized using 50 M of KOH as a mineralizer were considered as 2.42 mol$\%$ K doped-PZT powders. And 2.42 mol$\%$ K doped-PZT has much higher mechanical quality factor than undoped PZT ceramics. The sintering properties showed 7.987 g/cm$^{3}$ of sintered density and 3$\~$4 $\mu$m of grain size.

• Cement Symposium
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• no.25
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• pp.41-47
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• 1997

• Journal of the Korean Ceramic Society
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• v.46 no.4
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• pp.372-378
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• 2009

The coloring agents $Cr_2O_3$ and $CrCl_3$ were manipulated in this study to synthesize ZnO-$Al_2O_3-Cr_2O_3$ system pigments by changing their mixing ratio. The addition of varying amounts of mineralizer was also tested to obtain better color development of the pink pigment. In the synthesis of ZnO- $Al(OH)_3-Cr_2O_3-CrCl_3$ pigments, the best composition is $Cr_2O_3$-0.1 mole and $CrCl_3$-0.2 mole when $Cr_2O_3$ is partially substituted with $CrCl_3$ to synthesize them. Among the $ZnAl_{1.6-x}Cr_{0.2+x}O_4$ compositions to which a mineralizer was not added, ZnO-1mole, $Al(OH)_3$-1.7 mole, $Cr_2O_3$-0.075 mole, and $CrCl_3$-0.15 mole showed a desirable pink hue. The measurements of pigments $L^*$, $a^*$ and $b^*$, were $L^*$ 81.81, $a^*$ 16.65 and $b^*$ 0.45, and when the synthesized pigments were applied to a zinc glaze, the measurements were $L^*$ 60.41, $a^*$ 28.39, and $b^*$ 16.97. When adding a mineralizer, a 2 wt% addition resulted in the most favorable pink color. The composition for the most favorable result that included a mineralizer was $Al(OH)_3$-1.8 mole, $Cr_2O_3$-0.05 mole, and $CrCl_3$-0.1 mole, and the calcination temperature was $1250^{\circ}C$. The pigment color analysis showed $L^*$ 82.52, $a^*$17.14 and $b^*$-1.18, and the measurements of $L^*$, $a^*$ and $b^*$ in the glaze were $L^*$ 60.97, $a^*$ 28.77 and $b^*$ 13.72.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.254-262
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• 1996

$Pb(Zr_{0.52}Ti_{0.48})O_{3}$ (PZT) ceramics were prepared with uniform particle size of $1~3\;\mu\textrm{m}$ by hydrothermal synthesis at various conditions, such as hydrothermal reaction temperature, concentration of mineralizer and reaction time. PZT ceramics were formed above $180^{\circ}C$ for 2 hrs reaction using 10 M KOH solution as a mineralizer, but reaction condition was slightly different by starting materials. Morphology and characterization of PZT powders were investigated by XRD and SEM. By increasing the reaction temperature, KOH concentration and reaction time, the composition of the PZT phase tended to be homogeneous phase.

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.05a
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• pp.96-96
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• 2002

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.47-58
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• 1997

In this study single crystalline corundum ($\alpha$-$Al_2O_3$) powders were prepared from gibbsite using hydrothermal growing processes. Addition of a mineralizer and the characteristics of solid substances were investigated to find their effects on the size distribution and crystalllnity of products. Experimental results showed that as the concentration of potassium hydroxide (KOH), a mineralizer, the particle size of corundum powders became larger at lower reaction temperatures. However, the size of corundum powders became smaller as the concentration of gibbsite increased in the feedstock. The hydrothermal synthetic conditions are also strongly dependent on the properties of hydrothermal solutions. Corundum powders which have the weight mean particle size of 1~10 $\mu\textrm{m}$ with shapes of hexagonal were prepared in this experiment.