• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.401-402
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• 2005

The important parts of material science in the film preparation fields and sol-gel technology are presented. For the present work, a series of amorphous films was prepared in air by sol-gel method without using some alkoxide stabilizer, which reduces the reactivity of the metal alkoxides. The choice of precursors can affect the chemical-reaction kinetics, microstructures and properties of the product. In this report author compared the crystallization behavior of oxide functional films derived from the same precursors, stressing the influence of experiment conditions and where it was possible to obtain the uniform amorphous or crystalline dielectric films. A short analysis of sol-gel technology and thin film methods about development of dielectric materials has been given.

• 공업화학
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• 제18권6호
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• pp.568-574
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• 2007

투명결정화 유리의 전구체로서 균열이 없는 $Li_2O1{\cdot}7Al_2O_3{\cdot}8.6SiO_2$ 조성인 다공성 괴상 겔을 formamide를 첨가한 알콕시드 용액으로부터 sol-gel방법으로 합성하였다. 겔 합성에서 겔화 활성화 에너지, 비표면적, 습윤겔의 완전 탈수에 필요한 온도, 기공의 부피 및 기공크기와 분포를 측정하였고, 겔의 결정화온도를 검토하고자 시차열분석을 실시하였다. 겔화의 활성화에너지는 가수분해에 필요한 물의 첨가량에 따라 13~14 kcal/mol 범위를 나타내고, 물의 첨가량이 가수분해시 필요한 이론량의 3배 이상일 경우, $70{\sim}75^{\circ}C$, 건조속도 0.1~0.3 %/h에서는 겔의 균열을 방지할 수 있어 안정한 괴상 겔을 제조할 수 있었다. $180^{\circ}C$에서 건조한 겔체는 비표면적, 기공부피 및 기공크기분포는 $239.40m^2/g$, 0.001~0.03 mL/g 그리고 1~122 nm 반지름의 미세구조로 된 투명 겔체로서 다공질 물질임이 확인되었고, 건조겔의 시차열분석 결과 $800^{\circ}C$ 부근에서 1차 발열피크, $980^{\circ}C$ 부근에서가 2차 발열피크가 확인되어 결정화가 일어남을 알 수 있었다.

• 분석과학
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• 제26권3호
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• pp.205-210
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• 2013

졸-겔법에 의한 LAS계 결정화 유리합성공정에서 출발물질로 사용된 금속 알콕사이드의 조성비, 조핵제의 첨가량 및 열처리조건이 생성된 유리의 결정화 특성에 미치는 영향을 조사하였다. LAS 유리전구체의 겔화시간은 $TiO_2$의 첨가량이 늘어남에 비례하였고, 금속 알콕사이드 중의 TEOS의 몰비가 증가함에 따라서 폭발적으로 증가하였다. 또한 TEOS의 조성비가 커지면 LAS계 유리의 결정화 온도는 증가 하였지만, $TiO_2$ 첨가량의 영향은 미미하였다. 그리고 $TiO_2$의 첨가량이 늘어나면 낮은 온도에서도 결정성이 증가하는 것으로 나타나 이는 조핵제가 LAS계 결정화 유리의 결정성을 향상시키는 것으로 판단되었다.

• 한국세라믹학회지
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• 제32권3호
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• pp.305-312
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• 1995

Thin films of Pb(Mg, Zn)1/3Nb2/3O3 were fabricated by spin coating the Pb-Mg-Zn-Nb-O complex alkoxide sols on(111) Pt-coated MgO (100) planes. It was observed that the content of H2O and the rheological characteristics of sol greatly influenced the orientation of perovskite grains after thin-film formation. A strong preferential orientation of (100)-type planes of the perovskite grains was obtained for the sol aged for 15 days with the molar ratio of H2O to total metal alkoxides=2. As small angle X-ray scattering experiment in the Porod region was performed to correlate the observed preferential orientation with the network structure of precursors at various stage of aging. It was shown that the degree of branching of the Pb-Mg-Zn-Nb-O precursor chain had a direct effect on the preferred oreintation, and weakly branched precursor systems led to highly oriented grains after thin-film formation.

• 한국광물학회지
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• 제20권3호
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• pp.155-163
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• 2007

국내의 실리카 광물인 규질이암으로부터 실리콘알콕사이드와 같은 실리콘 유기화합물을 합성하였다. 이 실험에서는 알카리금속염 촉매 존재 하에서 트리에탄올아민과 규질이암의 반응에 의해 트리에탄올아민의 치환체인 트리스실라트라닐옥시에틸아민의 합성이 관찰되었다. 이 트리스실라트 라닐옥시에틸아민은 산성촉매인 발연황산의 존재 하에서 메탄올과의 반응으로 메톡시실란을 얻을수가 있었으며, 이 메톡시실란과 메탄올과의반응으로 테트라메톡시실란이 합성되었다. 반응의 중간 생성물 및 최종 산물은 FT-IR, XRD, SEM, 1H and 13C NMR 및 가스크로마토그래피에 의해 확인할 수 있었다.

• 한국세라믹학회지
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• 제23권4호
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• pp.27-34
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• 1986

In the present study an attempt was made to synthesize $10TiO_2$.$90SiO_2$ glass by Sol-Gel process. Tetra-ethyl-ortho-silane and titanium-iso-propoxide were used as precursors. As the mutual solvent ethanol and iso-propanol were used. TEOS was partially hydrolyzed with one-fold mole of $H_2O$ prior to the reaction with titanium-iso-propoxide to control the difference of hydrolysis rate of the two metal alkoxides. At gelling temperature higher than 6$0^{\circ}C$ it was difficult to obtain monolithic gels. At such a low temperature as 85$0^{\circ}C$ clear amorphous gel derived glass with Si-O-Ti bonding was obtained.

• 한국세라믹학회지
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• 제30권7호
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• pp.535-542
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• 1993

It was investigated in this study that a preparation method, activation energy, surface area, pore volume, pore size distribution and DTA analysis of the dry gel in process of producing monolithic porous gel in Li2O-Al2O3-TiO2-SiO2 system by the sol-gel technique using metal alkoxides. Activation energy for gellation according to the variation of water concentration and the kind of catalysts ranged from 10 to 20kcal/mole. Monolithic dry gels were prepared after drying at 9$0^{\circ}C$ when the amount of water for gellation was 4~8 times more than the stoichiometric amount, that was necessary for the full hydrolysis of the mixed metal alkoxide. The specific surface area, the pore volume, the average pore radius of the dried gel at 18$0^{\circ}C$ according to the various kinds of catalyst were about 348~734$m^2$/g, 0.35~0.70ml/g and 10~35$\AA$, respectively. It showed that the dry gels were porous body. As a result ofthe analysis of DTA, it was confirmed that the exothermaic peaks at 715$^{\circ}C$ and 77$0^{\circ}C$ was clue to the crystallization of dried gel.

• 한국세라믹학회지
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• 제25권5호
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• pp.541-551
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• 1988

The purpose of this investigation was to prepare multicomponent monolithic Li-Al-Si gels of composition(mol%) 16.67 Li2O-16.67 Al2O3-66.67 SiO2 and to convert the gels to monolithic glass-ceramic at low temperature without melting. The hydrolysis, DTA, TGA, TMA, SEM, pore distribution, density and the activation energy for crystallization of the glass-ceramic formation with rawmaterials of which tetraethl orhosilicate of networkforming cation(Si) is partially hydrolyzed, aluminum isoproxide and lithium methoxide prepared by Li-metal react with methanol were studied. The results were as follows : 1) Monolithic gels which were added with additional water, resulting in a total water content 2.5 to 3.0 times the stoichiometric amount required to fully hydrolyze the alkoxides. 2) Specimens were dried to form crylinders 60mm in length and 40mm in diameter in about 800 hrs at 5$0^{\circ}C$. 3) $\beta$-eucryptite crystals and $\beta$-spodumene crystals were detected in samples heated above 75$0^{\circ}C$. 4) Within the temperature and range of 25-50$0^{\circ}C$ and 1,00$0^{\circ}C$ the thermal expansion coefficient for crystallized samples were shown as 2.6-5.7$\times$10-7/$^{\circ}C$ and 7.4-12.5$\times$10-7/$^{\circ}C$, respectively. 5) The activation energy for the crystal growth was 11.01kcal/mol at 794$^{\circ}C$ to 85$0^{\circ}C$.

• 한국세라믹학회지
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• 제32권4호
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• pp.507-515
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• 1995

The monolithic dry gels of the Li2O-Al2O3-TiO2-SiO2 system were prepared by the sol-gel technique using metal alkoxides as starting materials to obtain monolithic glass-ceramics at low temperature without melting. Activation energy for the crystal growth of the gel with 6.05% TiO2, nucleating ageng, for the preparation of Li2O-Al2O3-TiO2-SiO2 system glass-ceramic was 101.14kcal/mol. As a result of the analysis of DTA & XRD, it was confirmed that the crytallization of Li2O-Al2O3-TiO2-SiO2 system glass-ceramic was the most efficient when 6.05% TiO2, nucleating agent, was added. $\beta$-eucryptite solid solution crystals and $\beta$-spodumene solid solution crystals were detected in the sample heat treated above 85$0^{\circ}C$. The sintered gel heat treated at 85$0^{\circ}C$ had the specific surface area of 185$m^2$/g, the pore volume of 0.19cc/g and the average pore radius of 20.8$\AA$. This shows that the sintered gel is also comparatively porous material. In temperature range of 25~85$0^{\circ}C$ thermal expansion coefficient of the specimen which was crystallized for 10hrs at 85$0^{\circ}C$ was 6.7$\times$10-7/$^{\circ}C$, which indicated that the crystallized specimen was turned out to be the glass-ceramic with low thermal expansion.

• 센서학회지
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• 제4권4호
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• pp.75-80
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• 1995

금속 alkoxide를 출발물질로 PZT-PNN 3성분계 압전박막을 제작하여, 박막의 결정성과 전기적 특성을 평가하였다. 박막의 X-RD 분석결과 $550^{\circ}C$ 소결온도에서 결정성이 가장 양호하였다. D-E 이력곡선의 관측 결과 항전계는 28.8 kV/cm, 잔유분극은 $18.3\;{\mu}C/cm^{2}$ 이었다. 박막의 진성파괴전압은 $76.0\;{\sim}\;27.0\;MV/m$이었고, 소결온도가 상승함에 따라 특성이 저하되었다. 박막의 비유전율은 조성비에 따라 (50:40:10)은 406, (50:30:20)은 1084, (45:35:20)은 723, (40:40:20)은 316이었다.