• Membrane Journal
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• v.22 no.6
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• pp.435-440
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• 2012

In this study, nanoporous HKUST-1 membranes were synthesized by solvothermal method. It is very difficult to prepare uniform and crack-free HKUST-1 layer on macroporous alumina support by in-situ solvothermal method. In this study, continuous and crack-free HKUST-1 membranes could be obtained by spraying solvothermal precursor solution on the heated alumina support, followed by solvothermal synthesis. HKUST-1 membranes were characterized by XRD, FE-SEM and single gas permeation experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.225-225
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• 2010

박막 방식의 CIGS 태양전지는 공정이 복잡하고 대면적화가 어렵다는 단점을 가지고 있다. 이를 개선하기 위하여 후막 방식을 이용한 CIGS 태양전지에 대한 연구의 필요성이 대두되어지고 있다. 스크린 프린팅과 같은 후막공정은 나노 CIGS powder가 필요하다. CIGS 합성 방법 중에 solvothermal 방식이 다른 방식에 비해 균일한 크기의 구형의 나노입자를 대량생산이 쉽기 때문에 많이 연구되어지고 있다. 선행 연구 결과들은 CIS, CIGS 및 CGS는 solvothermal 법으로 합성 시 3개의 상이 모두 합성되며, 합성조건에 따라 상의 조성의 조절이 되지 않는다. 따라서 현재까지 solvothermal 법으로는 단일상의 CIGS 상의 합성이 보고되지 않고 있다. 본 연구에서는, solvothermal 방식을 이용하여 후막공정을 위한 CIGS powder를 합성하였다. 원료, 용매 및 합성 온도 등의 변화에 따른 상의 변화를 측정하였고, 원료의 농도에 따른 powder의 크기 및 형상을 제어 하였다. 또한 CIGS powder를 이용하여 페이스트을 제조한 후, 이 페이스트를 가지고 태양전지를 위한 치밀한 후막을 제조할 수 있었다.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.685-690
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• 2011

In this study, a solvothermal reaction to prepare nanocrystalline titania was carried out using $TiCl_4$ and mixed solvents of alcohol and water. The effects of the type and the composition of alcohol on the crystal structure and agglomeration of final $TiO_2$ products were investigated. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscopy (SEM). In the solvothermal reaction using the n-butanol solutions with different volume ratios of n-butanol/water (100/0, 75/25, 50/50, 25/75, 0/100), the extent of agglomeration of obtained rutile $TiO_2$ was found to change with the volume ratio of n-butanol/water, and the n-butanol/water ratio of 75/25 revealed the best result for the preparation of well-dispersed nanocrystalline $TiO_2$ powders. The crystal phase of $TiO_2$ prepared through the solvothermal reaction changed with the type of alcohol in solvent (alcohol/water = 75/25). $TiO_2$ products obtained with the aqueous solutions of methanol, ethanol and isopropanol have an anatase phase, while that with n-butanol has a rutile phase. The results showed that, in the solvothermal reaction using both $TiCl_4$ as a starting material and the alcohol-water mixed solvents without any other additive, the enhancement of dispersion and control of crystal structure of $TiO_2$ products can be feasible by simply varying the composition and type of alcohol in the mixed solvents.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1921-1923
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• 2013

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.48.2-48
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• 2003

• Korean Journal of Materials Research
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• v.26 no.5
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• pp.246-249
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• 2016

Nickel powders were prepared under solvothermal condition by precipitation from metal nitrates with aqueous ammonium hydroxide. The powders were obtained at in a temperature range of $190-250^{\circ}C$ for 6h. The morphology and size of nickel powders were studied as a function of reaction temperature. The synthesis of nickel crystalline particles is possible under a solvothermal conditions in ethylene glycol solution. Characterization of the synthesized nickel powders were studied by XRD, SEM(FE-SEM) and TG/DSC. X-ray diffraction analysis of the synthesized powders indicated the formation of nickel structure after reaction. The average crystalline sizes of the synthesized nickel powders were in the range of 200-1000 nm; and the distribution of the powders was broad. The shape of the synthesized nickel particles was almost spherical. The morphology of synthesized nickel powders changed with reaction condition. It was possible to synthesize nickel powders directly in ethylene glycol without reducing agent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.732-734
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• 2003

A solvothermal synthetic method to $BaTiO_3$ nanoparticle has been investigated in toluene solution with $BaTi(OR)_6$ as precursor. A precursor prepared from barium metal with toluene, isopropanol and titanium isopropoxide was used as a starting material. Weight ratio of precursor to solvent prepared in the mixture are 5/100, 10/100, 20/100 and 50/100wt%. At the weight ratio of 50/100wt%, $BaTiO_3$ butterfly twin crystalline(${\fallingdotseq}100nm$) was obtained after synthesis at $250^{\circ}C$ for 20hrs in an autoclave. X-ray diffraction and transmission electron microscopy showed that the product of 50/100wt% has crystallization. At 5/100, 10/100, and 20/100wt%, however, red colloidal solution was obtained after synthesis and crystalline phase of $BaTiO_3$ was not produced.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.655-658
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• 2001

The generation of fly ash tends to increase yearly so that this is currently considered a big environmental concern, which requires appropriate treatment approaches. In this research the consolidation of incineration fly ash by the hot-press solvothermal reaction was investigated to provide an alternative process for the treatment and utilization of this waste material. Results showed that at reaction conditions of 52 K treatment, 20 ㎫ pressure and 60 minutes treatment time, the resulting consolidate exhibited a compressive ness strengths of 37-40 ㎫, a tensile strength of 6.5-7.0 ㎫ and a Rockwell hardness of 20-23 RH15W. These properties are comparable to the compressive ness strength of Portland cement which ranges from 30-40 ㎫ as well as with the tensile strengths of mortar, ganite, artificial lightweight aggregate and solidified high connote whose values are 2-2.5 ㎫, 5-9 ㎫, 5-10 ㎫ and 3-5 ㎫ respectively- Furthermore, by mixing fly ash with glass at 50% ratio and then subjecting to similar treatment conditions, a consolidate with even higher tensile strength of 12.5-13.3 ㎫ and hardness of 77-80 RH15W may be achieved.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.78-81
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• 2012

$Y_2O_3$ nanomaterials have been widely used in transparent ceramics and luminescent devices. Recently, many studies have focused on controlling the size and morphology of $Y_2O_3$ in order to obtain better material performance. $Y_2O_3$ powders were prepared under a modified solvothermal condition involving precipitation from metal nitrates with aqueous ammonium hydroxide. The powders were obtained at temperatures at $250^{\circ}C$ after a 6h process. The properties of the $Y_2O_3$ powders were studied as a function of the solvent ratio. The synthesis of $Y_2O_3$ crystalline particles is possible under a modified solvothermal condition in a water/ethylene glycol solution. Solvothermal processing condition parameters including the pH, reaction temperature and solvent ratio, have significant effects on the formation, phase component, morphology and particle size of yttria powders. Ethylene glycol is a versatile, widely used, inexpensive, and safe capping organic molecule for uniform nanoparticles besides as a solvent. The characterization of the synthesized Y2O3 powders were studied by XRD, SEM (FE-SEM) and TG/DSC. An X-ray diffraction analysis of the synthesized powders indicated the formation of the $Y_2O_3$ cubic structure upon calcination. The average crystalline sizes and distribution of the synthesized $Y_2O_3$ powders was less than 2 um and broad, respectively. The synthesized particles were spherical and hexagonal in shape. The morphology of the synthesized powders changed with the water and ethylene glycol ratio. The average size and shape of the synthesized particles could be controlled by adjusting the solvent ratio.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.537-542
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• 2003

($Y_{l-x}$ $Gd_{x}$ )$O_2$$_3$: $Eu^{ 3＋}$ red phosphors were prepared with the solvothermal synthesis using the 2-methoxy-ethanol solvents and the emission intensity was investigated that applied with the 254 nm wavelength and the maximum excitation wavelength for energy source. The used solvents for the solvothermal synthesis were made of nitrate salt solutions of Y, Gd and Eu. These solutions dropped in autoclave have be reacted with the solvothermal synthesis at $200^{\circ}C$ for 5hrs and the red phosphors prepared here in were showed the pure cubic phase after annealing at $1000∼1200^{\circ}C$. The brightness of ($Y_{l-x}$ $Gd_{x}$)$_2$$O_3$: $Eu^{3＋}$ phosphors particles was increased as an increase of Gd ratio. The maximum excitation wavelengths of ($Y_{l-x}$ $Gd_{x}$ )$_2$$O_3$: $Eu^{3＋}$ / phosphors particles were increased according to increasing Gd ratio from 253 nm to 259 nm wavelength. The maximum emission intensity of $Gd_2$$O_3$: $Eu^{3＋}$ (Y/Gd = 1/0) phosphors particles under UV 259 nm was found to be higher than the commercial product of $Y_2$$O_3$: $Eu^{3＋}$ phosphors.