• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.642-648
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• 2002

Barium Titanate(BaTiO$_3$) nanoparticles were prepared at 22$0^{\circ}C$ through glycothermal process by using barium hydroxide and amorphous titanium hydrous gel as precursor and 1,4-butanediol and distilled water as solvent. It is demonstrated that the size of BaTiO$_3$ particles can be controlled by reaction conditions such as various content of 1,4-butanediol/distilled water volume ratio. This processing method can fabricate BaTiO$_3$ powders, which have a narrow distribution and exhibit good dispersion. The particle size of BaTiO$_3$ powders obtained by glycothermal process were about 50 nm to 200 nm on the condition that reaction temperature was 22$0^{\circ}C$ and holding time was 24 h.

• Journal of the Korean Ceramic Society
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• v.34 no.11
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• pp.1159-1164
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• 1997

Magnetite(Fe3O4) powders were synthesized through glycothermal reaction by using crystalline $\alpha$-FeOOH as precursor and ethyleanne glycol as solvent. The phase, morphology and particle size of synthesized powders were characterized by XRD and an SEM. When only ethylene glycol was used as solvent, the phase was transformed from $\alpha$-FeOOH to $\alpha$-Fe2O3 and finally Fe3O4 at 27$0^{\circ}C$ for 6hr without morphological change. But by addition of water, Fe3O4 powders were synthesized at 23$0^{\circ}C$ for 3hr through solution-recrystalization process. As the content of water addition increased, the particle shape changed from sphere to octahedron and the partcle size increased. When the excess amount of water added, residual $\alpha$-FeOOH or $\alpha$-Fe2O3 was recrystalized.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.26.2-26
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• 2003

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.47.1-47
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• 2002

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.167-168
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• 2009

Phase pure barium magnesium tantalate $Ba(Mg_{1/3}Ta_{2/3})O_3$(BMT) nanopowders were synthesized at temperature as low as $220^{\circ}C$ through glycothermal reaction by using $Ba(OH)_2{\cdot}8H_2O$, $Mg(NO_3){\cdot}6H_2O$, and $TaCl_5$ as precursors and 1,4-butandiol as solvent. XRD, SEM, and TGA data support that glycothermal processing method provides a simple low temperature route for producing fine grained BMT nanopowders without alkaline mineralizers. BMT nanopowders synthesized at $220^{\circ}C$ showed more homogenous with rounded morphologies.

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.903-906
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• 2002

Nanosized $Mn_xFe_2O_4$ powders were prepared in ethylene glycol solution under mild temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. The average size and distribution of the synthesized $Mn_xFe_2O_4$ powders was about 20 nm and broad, respectively. The phase of synthesized particles was crystalline reacted at 200${\circ}C$ for 6h. The magnetic properties of the synthesized $Mn_xFe_2O_4$ powders were about 35-60 (emu/g) with superparamagnetic character.

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.11a
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• pp.118-118
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• 2001

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.567-572
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• 1997

The ZnO powder was prepared under glycothermal conditions by precipitation from metal nitrates with aqueous potassium hydroxide. The fine powder was obtained at temperatures as low as 225 to $275^{\circ}C$, The microstructure and phase of the powder were studied by SEM and XRD. The properties of the ZnO powder were studied as a function of various parameters (reaction temperature, reaction time, solid loading, etc). The average particle size of the ZnO increased with increasing reaction temperature. After glycothermal treatment at $225^{\circ}C$ for 8 h, the average particle size of the ZnO powder was about 150 nm and the particle size distribution was narrow.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.319-319
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• 2005

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.386-386
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• 2012

For white light emitting diode (LED) applications, it has been reported that Y3Al5O12:Ce3+ (YAG:Ce) in nano-sized phosphor performs better than it does in micro-sized particles. This is because nano-sized YAG:Ce can reduce internal light scattering when coated onto a blue LED surface. Recently, there have been many reports on the synthesis of nano-sized YAG particles using bottom-up method, such as co-precipitation method, sol-gel process, hydrothermal method, solvothermal method, and glycothermal method. However, there has been no report using top-down method. Top-down method has advantages than bottom-up method, such as large scale production and easy control of doping concentration and particle size. Therefore, in this study, nano-sized YAG:Ce phosphors were synthesized by a high energy beads milling process with varying beads size, milling time and milling steps. The beads milling process was performed by Laboratory Mill MINICER with ZrO2 beads. The phase identity and morphology of nano-sized YAG:Ce were characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. By controlling beads size, milling time and milling steps, we synthesized a size-tunable and uniform nano-sized YAG:Ce phosphors which average diameters were 100, 85 and 40 nm, respectively. After milling, there was no impurity and all of the peaks were in good agreement with YAG (JCPDS No. 33-0040). Luminescence and quantum efficiency (QE) of nano-sized YAG:Ce phosphors were measured by fluorescence spectrometer and QE measuring instrument, respectively. The synthesized YAG:Ce absorbed light efficiently in the visible region of 400-500 nm, and showed single broadband emission peaked at 550 nm with 50% of QE. As a result, by considering above results, high energy beads milling process could be a facile and reproducible synthesis method for nano-sized YAG:Ce phosphors.