• 한국세라믹학회지
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• 제37권6호
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• pp.564-568
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• 2000

Spinel LiMn2O4 catalyst with submicron and single phase particles was synthesized at 48$0^{\circ}C$ for 12 hr in air by a sol-gel method. The spinel LiMn2O4 was deoxidized by hydrogen at various temperatures. Effects of physiochemical properties of the catalyst reduced by hydrogen were examined with X-ray diffractometer, thermogravimetric analysis and scanning electron microscope. The decomposition rate of carbon dioxide was measrued using the catalyst deosidized at 35$0^{\circ}C$.

• 한국세라믹학회지
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• 제31권4호
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• pp.427-435
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• 1994

Cu-metallized low firing temperature substrates were synthesized by cofiring green sheet of cordierite-based glass with Cu. By Sol-Gel method, Cu powder was coated with borosilicate gel which should act as a glass frit in Cu paste during cofiring. Theoretical weight ratios of Glass/Cu were controlled to be 2.5, 5, 10 and 15% by varying alkoxide concentrations. Average particle size of coated Cu was 0.629~0.674 ${\mu}{\textrm}{m}$ in comparison to that of as-received Cu(0.596 ${\mu}{\textrm}{m}$), which increased with alkoxide concentration but did not increase above certain concentration. The weight ratios of coated layer were 2.11~5.37%. The properties of Cu-metallized low firing temperature substrate, cofired at 90$0^{\circ}C$ for 1h under H2/N2 atmosphere, were as follows; sheet resistance was 13~43 m{{{{ OMEGA }}/$\square$, adhesion strength was 1.0~2.1 kgf/$\textrm{mm}^2$. From the observations of SEM photographs, the gel coated on Cu performed excellently as a glass frit.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.135-135
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• 2003

This paper presents the preparation of SnO$_2$ films by Sol-Gel process and using spin coating method, and their sensing properties in CO gas. Experimental procedure consisted of following steps: (1) Tin chloride(SnCl$_4$) and Ammonium hydrogen carbonate (NH$_4$HCO$_3$) were used as precursors; (2) the Sol solution with concentration of about 10wt% SnO$_2$ was prepared from washed Gel-precipitate for spin coating step; (3) thereafter, the coating solution was dropped onto the alumina (Al$_2$O$_3$) substrate that was then spun, the spin coating was carried out with total 10 times; (4) finally, the films were calcined for 3 hours at 50$0^{\circ}C$ or higher temperature (600, 700, 800 or 90$0^{\circ}C$) in order to obtain various gram sizes. The average grain size was calculated by Scherrer's equation using main peaks in XRD spectra; meanwhile the thickness, microstructure and surface morphology of the films were observed by FE-SEM.

• Journal of Electrochemical Science and Technology
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• 제10권4호
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• pp.394-401
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• 2019

The unique study of TiO₂ sol-gel modified carbon paste electrode (CPE) nanocomposites have been developed for electrochemical sensor detecting fipronil pesticide compound. We develop the easy synthesized TiO₂ via a sol-gel method and modified in CPE which applied electrochemical system as cyclic voltammetry (CV) because the concentration is proportional with current peaks. We discover the TiO₂ optimal mass used of 0.1 g which is compared with 0.7 g carbon and 0.3 mL paraffin. It has high-current anodic (Ip_a) of 1.13×10³ μA and high-current cathodic (Ip_c) -0.96×10³ μA in scan rate of 0.5 V/s. The limit of detection (LOD) of fipronil has been determined of 34.0×10^-5 μM in percent recovery of 0.8%. Its high-stability for lifetime TiO₂-CPE nanocomposites was expressed for 13 days which mean that can be used for detecting fipronil pesticide.

• 전기화학회지
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• 제14권1호
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• pp.27-32
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• 2011

Cr을 첨가한 $Li_4Ti_5O_{12}$의 전기화학적 특성을 고찰하였다. 산화물에 금속원자가 치환될 경우에 결정구조가 변화되며, $Li_4Ti_5O_{12}$의 전기화학적 특성이 변화하게 된다. 졸-겔법을 이용하여 $Li_4Ti_{5-x}Cr_xO_{12}$ (x = 0~0.2)를 제조하였으며, 전기로에서 $800{\sim}850^{\circ}C$로 공기중에서 12시간 동안 열처리하였다. 시료의 물리적인 특성은 TG-DTA, XRD, SEM, FT-IR을 사용하여 측정하였으며, 전기화학적인 특성은 0.01~2.0V의 범위에서 배터리충방전기를 사용하여 측정하였다. $Li_4Ti_5O_{12}$는 1C에서 169.9 mAh/g의 용량을 나타내었으며, 0.1C로 변화되었을 경우에 초기용량의 97.5%를 나타내었다. $Li_4Ti_{4.9}Cr_{0.1}O_{12}$ 시료는 1C에서 193.8 mAh/g의 용량을 보였으며, 0.1C에서는 초기용량의 98.8%를 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.622-628
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• 2013

Nanocrystalline spinel lithium manganese oxide ($LiMn_2O_4$) powders with narrow-size-distribution, pure-phase particles, and high crystallinity with an average crystallite size of about 70 nm were synthesized at $600^{\circ}C$ for 6 h in air by freeze drying method. Spinel $LiMn_2O_4$ is also prepared by sol-gel using citric acid as a chelating agent. The influence of different parameters such as pH conditions, solvent, molar ratio of citric acid to total metal ions, calcination temperature, starting material on the structure, morphology and purity of this oxide was investigated. The results of sol-gel method show that pure $LiMn_2O_4$ with average crystallite size of about 130 nm can be produced from nitrate salts as starting materials at $800^{\circ}C$ for 6 h in air. The optimum pH and molar ratio of chelating agent to total metal ions are $4{\leq}pH{\leq}6$ and 1.0, respectively. A possible mechanism on the formation of the nanocrystallines synthesized by sol-gel was also discussed. At the end a comparison of the differences between two methods was made on the basis of x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) tests.

• 멤브레인
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• 제18권2호
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• pp.176-184
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• 2008

본 연구에서 졸-겔 방법에 의하여 나노 기공을 가지는 세라믹막을 제조하여 단일 조성의 헬륨과 질소를 가지고 기체투과 실험을 수행하였다. 기공 크기 $0.1{\mu}m$, 기공율 32%의 평막형 ${\alpha}-Al_2O_3$ 지지체를 제조하였으며, 지지체를 담지하여 코팅하는 방법으로 4nm의 기공 크기를 가지는 ${\gamma}-Al_2O_3$ 중간층을 제조하였다. 실리카 졸은 TEOS의 산 촉매 가수분해와 축중합반응을 통하여 합성하였다. 막은 딥코팅과 소결과정을 거쳐 제조되었다. 졸-겔 법에 의해 합성된 세라믹 막을 통한 헬륨, 질소 투과 실험은 기체의 투과 특성을 파악하기 위하여 시행하였다. 질소에 대한 헬륨의 선택도는 $100{\sim}160$ 정도였으며 헬륨의 투과도는 $303{\sim}363K$의 온도 범위에서 $10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ 정도였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.106-108
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• 2001

As 3V cathode material, a new doping spinel material, LiMn1.6Se0.4O4 powder with a phase-pure polycrystalline was synthesized by a sol-gel method. In spite of Jahn-teller distortion in 3V region($2.4{\sim}3.5V$), the LiMn1.6Se0.4O4 electrode shows no capacity loss. The material in the 3V region initially delivers a discharge capacity of 100mAh/g which increase with cycling to reach 105mAh/g after 90cycles. And 5V cathode material LiNi0.5-xMxMn1.5O4(M=Cr, V, Fe) compounds have been synthesized by sol-gel method. a series of electroactive spinel compounds, LiNi0.5-xMxMn1.5O4(M=Cr, V, Fe) has been studied by crystallographic and electrochemical methods. The material presents only one plateau at around 4.5 V vs. Li/Li+ with a large discharge capacity of 152mAh/g and fairly good cyclability.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.77-82
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• 2015

To increase the performance of solid oxide fuel cell operating at intermediate temperature ($600^{\circ}C{\sim}800^{\circ}C$), $Sm_{0.2}Ce_{0.8}O_2$ (SDC) thin layer was applied to the $La_{0.8}Sr_{0.2}Mn_{0.8}Cu_{0.2}O_3$ (LSMCu) cathode by sol-gel coating method. The SDC was employed as a diffusion barrier layer on the yttria-stabilized zirconia(YSZ) to prevent the interlayer by-product formation of $SrZrO_3$ or $La_2Zr_2O_7$. The by-products were hardly formed at the electrolyte-cathode interlayer resulting to reduce the cathode polarization resistance. Moreover, SDC thin film was coated on the cathode pore wall surface to extend the triple phase boundary (TPB) area.

• 한국자기학회지
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• 제13권1호
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• pp.21-28
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• 2003

BaF $e_{12-2x}$ $Co_{x}$ $Ti_{x}$ $O_{19}$ (0$\leq$x$\leq$1.0) 분말을 sol-gel을 이용하여 제조하였다. 결정학적 및 자기적 성질을 x선 회절분석기(XRD), 열분석기(TG/DTA), 적외선분광기(FT/IR), 시료진동형자화율측정기(VSM), 및 Mossbauer 분광기를 이용하여 연구하였다. X선 회절 분석결과 격자상수 $\alpha$와 c는 x=0.0일 때 $\alpha$=5.822, c=23.215 $\AA$에서 x=1.0일 때 $\alpha$=5.895, c=23.295 $\AA$으로 x의 치환량이 늘어남에 따라 증가함을 알 수 있었다. Mossbauer 스펙트럼 분석 결과 $Co^{2+}$- $Ti^{4+}$ 이온의 site 점유도가 포화자화 값과 보자력을 조절할 수 있음을 알 수 있었다. $Co^{2+}$와 $Ti^{4+}$ 의 치환량이 증가함에 따라 Curie 온도는 선형적으로 감소함을 알 수 있었다.