• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.283-283
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• 2006

Multigram-scale product exclusively containing magnetic carbon nanoparticles (MNCPs) with uniform size was successfully fabricated without a specific separation process. The iron-doped PPy nanoparticles were synthesized by micelle templating and used as the carbon precursor in order to generate MCNPs. The magnetic carbon nanoparticles possessed a microporous structure and exhibited ferromagnetic properties at room temperature. This approach may be an effective alternative to generate magnetic carbon nanoparticles against the conventional arc-discharge technique.

• Journal of the Korean Ceramic Society
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• v.30 no.1
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• pp.34-40
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• 1993

ORMOSIL was synthesized with inorganic precursor, TEOS and organic precursor, PDMS, and the variation of composite properties according to the concentration of HCl, solvent content and reaction time were studied. As the concentration of HCl increased, condensation reaction was well proceeded and more regularly distributed network was observed. Increase in reactivity was found with the amount of solvent, and composite had a tendency of forming more porous microstructure as reaction time was increased, which had no influence on the bonding degree.

• Korean Journal of Materials Research
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• v.9 no.2
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• pp.155-162
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• 1999

Zirconia thin films of uniform structure were fabricated by plasma-enhanced metal-organic chemical vapor deposition. Deposition conditions such as substrate temperature were observed to have much influence on the formation of zirconia films, therefore the mechanism of decomposition of $Zr[TMHD]_4$precursor and film growth were examined by XRD, FT-IR etc., as well as the determination of the optimal deposition condition. From temperature dependence on zirconia, below the deposition temperature of 523K, the amorphous zirconia was formed while the crystalline of zirconia with preferred orientation of cubic (200) was obtained above the temperature. Deposits at low temperatures were investigated by FT-IR and the absorption band of films revealed that the zirconia thin film was in amorphous structure and has the same organic band as that of Zr precursor. In case of high temperature, it was found that Zr precursor was completely decomposed and crystalline zirconia was obtained. In addition, at 623K the higher RF power yielded the increased crystallinity of zirconia implying an increase in decomposition rate of precursor. However, it seems that RF power has nothing with the zirconia deposition process at 773K. It was found that the proper bubbler temperature of TEX>$Zr[TMHD]<_4$ precursor is needed along with high flow rate of carrier gas. Through AFM analysis it was determined that the growth mechanism of the zirconia thin film showed island model.

• Journal of the Korean Ceramic Society
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• v.41 no.5
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• pp.349-352
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• 2004

Organic-inorganic hybrid sol based on ZrO$_2$-SiO$_2$ system was prepared by sol-gel process. Firstly, ZrO$_2$ non-aqueous precursor sol was synthesized and then organosilane compounds which include epoxy silane (GPTS; 3-g1ycidoxypropyl tri-methoxysilane) and acryl silane (ACS; (3-(tri-methoxysilyl)propylmethacrylate)) were added to ZrO$_2$precursor sol for hybridization. Finally, com-mercial silica sol was added to improve the mechanical properties. Synthesized organic-inorganic Zr-hybrid sol was coated on polycarbonate substrate for enhancing it’s mechanical properties, especially hardness. Vicker’s hardness of polycarbonate sub strate was increased from 13.6 to 17.8 MPa and its pencil hardness was increased from 2 to 7 H, respectively, after coating and drying at 10$0^{\circ}C$ for 30 min.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1459-1461
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• 2009

In this study, we prepared the multi-refraction film thin by ink-jet technique with sol-gel precursor. The precursors were prepared by using some transition metal alk-oxide and the tetraethylorthosilicate (TEOS) mixed separately with n-Butyl Alcohol and PVB (Poly(vinyl butyral)).The structure and morphology of the resulting films were investigated by atomic force microscope (AFM). It is shown that the shape of the pattern of the films would affect the refraction proportion.

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.64-64
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• 2002

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.523-527
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• 2012

Silicon carbide (SiC) has recently drawn an enormous amount of industrial interest due to its useful mechanical properties, such as its thermal resistance, abrasion resistance and thermal conductivity at high temperatures. In this study, RF thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) was utilized for the synthesis of high-purity SiC powder from an organic precursor (hexamethyldisilazane, vinyltrimethoxysilane). It was found that the SiC powders obtained by the RF thermal plasma treatment included free carbon and amorphous silica ($SiO_2$). The SiC powders were further purified by a thermal treatment and a HF treatment, resulting in high-purity SiC nano-powder. The particle diameter of the synthesized SiC powder was less than 30 nm. Detailed properties of the microstructure, phase composition, and free carbon content were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), a thermogravimetric (TG) analysis, according to the and Brunauer-Emmett-Teller (BET) specific surface area from N2 isotherms at 77 K.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.480-484
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• 2004

$LiGaO_2$ films have been grown on Si (100) substrates using a new single precursor $[Li(OCH_2CH_2OCH_3)_2-Ga(CH_3)_2]_2$ under high vacuum conditions $(5{\times}10^{-6}Torr)$. The $[Li(OCH_2CH_2OCH_3)_2Ga(CH_3)_2]_2$ was synthe-sized and characterized by using spectroscopic methods and single-crystal X-ray diffraction analysis. The chemical composition, crystalline structure, and morphology of the deposited films were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The results show that polycrystalline $LiGaO_2$ films preferentially oriented in the [010] direction can be deposited on Si (100) at 500-550$^{\circ}C$ by metal organic chemical vapor deposition (MOCVD). The single precursor $[LiOCH_2CH_2OCH_3)_2-Ga(CH_3)_2]_2$ has been found suitable for chemical vapor deposition of $LiGaO_2$ thin films on Si substrates.

• Journal of Powder Materials
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• v.10 no.5
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• pp.310-317
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• 2003

Two-component ceramic (alumina-zirconia) composites were fabricated by a soft-solution process in which polyethylene glycol (PEG) was used as a polymeric carrier. Metal salts and PEG were dissolved in ethyl alcohol without any precipitation in 1:1 volume ratio of alumina and zirconia. In the non-aqueous system, the flammable solvent made explosive, exothermic reaction during drying process. The reaction resulted in formation of volume expanded, porous precursor powders by a vigorous decomposition of organic components in the precursor sol. The PEG content affected the grain size of sintered composites as well as the morphology of precursor powders. The difference of microstructure in sintered composite was attribute to the solubility and homogeneity of metal cations in precursor sol. At the optimum amount of the PEG polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. It made less agglomerated particles in the precursor sol and affected on uniform grain size in sintered composite.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 2000.06a
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• pp.151-163
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• 2000

A polymerized organic-inorganic complexation route is introduced for the synthesis of oxide ceramic powders. Polyvinyl alcohol was used as the organic carrier for precursor ceramic gel. Porous and soft powders, which have a high specific surface area, were obtained after calcinating the aerated precursors. The PVA content and its degree of polymerization had a significant influence on the homogeneity of the final powder. In particular, attrition milling process with the porous powder resulted in ultra-fine particles. In the case of the preparation of cordierite powder, nano-size powder, which has a high specific surface area of 181 ㎡/g, was obtained by the milling process. The complexation route was also applied to the synthesis of unstable phase in room temperature like beta-cristobalite, high temperature form of silica.