• 한국세라믹학회지
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• 제20권1호
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• pp.3-12
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• 1983

In the present study an attempt was made to synthesize the $Al_2O_3$.$2SiO_2$ glass in which atomic ratio is Al:Si=1:1 by sol-gel process. And at such a low temperature as 55$0^{\circ}C$ clear amorphous gel derived glass with Si-O-Al bonding was obtained. $Si(OC_2H_5)_4$ and $Al(NO_3)_3$.$9H_2O$ were used as the precursor and among the mutual solvents only n-butanol gave good results for the synthesis of the gel derived glass. Partial hydrolysis of TEOS with one-fold mol of $H_2O$ prior to the reaction with aluminum nitrate gave the better results., Total oxide content to the total reactants by weight was affective to the results.

• 공업화학
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• 제16권1호
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• pp.45-51
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• 2005

Aluminum nitrate 수용액을 원료로 사용하여 $K_2O-Li_2O-Al_2O_3$ 3성분계로부터 $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$를 합성하였다. 순수한 $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$의 합성을 위하여 원료물질은 $0.84K_2O{\cdot}0.082Li_2O{\cdot}5.2Al_2O_3$의 조성으로 액상상태에서 혼합되었다. 입자크기를 최소화하고 순수한 $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$를 합성하는데 있어서 분산첨가제와 용액의 pH의 영향을 조사하였다. 분산첨가제로써 에탄올을 0.0~4.0 M 첨가하였고 용액의 pH는 $NH_4OH$ 수용액과 $HNO_3$를 이용하여 조절하였다. 시료는 pH 1.0에서 7.5까지 0.5 간격으로 수집하였다. 각 시료들은 $1200^{\circ}C$에서 2 h 동안 하소한 후 XRD와 PSA 분석을 하였다. 용액의 pH는 입자크기와 상형성에 모두 중요한 영향을 미친 반면, 에탄올의 첨가는 입자크기에만 영향을 주었다. pH 조절에 $HNO_3$를 사용하였을 경우, $HNO_3$를 사용하지 않았을 때 보다 순수한 $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$ 상을 합성하는데 유리함을 알 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.191-191
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• 2003

가시광선영역에서 높은 광학적 투명도를 갖는 n-type 반도체인 ZnO 박막은 넓은 범위에서 응용되고 있다. 현재 ZnO 박막의 특성 향상을 위하여 여러 원소(Al, Ga)의 도핑을 시도하고 있다. 특히 Al-doped ZnO 박막은 sol-gel dip coating에 의해서도 높은 전기전도도와 투과율로 활발히 연구되고 있다 본 논문에서는 여러 도핑농도를 갖는 Al-doped ZnO 박막이 sol-gel dip coating법에 의해 준비되었다. Al-doped ZnO 박막은 zinc acetate [Zn($CH_3$COO$_2$)ㆍ2$H_2O$] powder 와 여러 도핑농도를 갖는 aluminum nitrate (Al(NO$_3$)$_3$ㆍ9$H_2O$) powder를 알코올에 용해하여 $H_2O$, Ethylene glycol, Ethylene diamine 등을 첨가하여 제조하였다 XRD와 SEM (Scanning electron microscope)이 막의 상형성 분석을 위해 이용되었으며, 가시광선 영역 투과율(UV/VIS spectrophotometer)과 표면전기저항(four point probe)이 주요 특성으로 분석되었다.

• Bulletin of the Korean Chemical Society
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• 제30권6호
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• pp.1388-1390
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• 2009

• 한국재료학회지
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• 제13권4호
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• pp.251-258
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• 2003

The effects of the salt and the precursor pH on the synthesizing behavior and the morphology of mullite have been studied. Two kinds of mullite precursor sols were prepared by the dissolution of two kinds of salt (aluminum nitrate enneahydrate, Al($NO_3$)$_3$ㆍ$9H_2$O; type I and aluminum sulfate 14∼18 water, (SO$Al_4$)$_3$$\cdot$$14∼18H_2$O; type II) into the mixture of colloidal silica sol, respectively. Precursor pH of the sols was controlled to the acidic (pH= 1.5∼2) and basic (pH= 8.5∼9) conditions. The co-products with nitrate and sulfate were completely eliminated at $500^{\circ}C$ and $850^{\circ}C$, respectively, which was confirmed by TG/DTA results. The synthesizing temperature of mullite phase was found to be above $1200^{\circ}C$ for pH= 1.5∼2 and above $1300^{\circ}C$ for pH= 8.5∼9 in type I. However, in type II, the synthesizing temperature of mullite was decreased to $850^{\circ}C$ for pH= 1.5∼2 and $1100^{\circ}C$ for pH= 8.5∼9. The grain size of the mullite synthesized at pH= 8.5∼9 was larger than that at pH= 1.5∼2 in overall heat-treated temperatures, showing smaller grain size in type II. Aspect ratio of the mullite grains was more increased at pH= 1.5∼2 than pH= 8.5∼9 in type I, showing similar aspect ratio at both pH conditions in type II. It was found that the synthesizing temperature and grain size were predominantly governed by the initial precursor pH and decomposition of the salt, with minor effect on the grain morphology.

• 한국재료학회지
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• 제12권7호
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• pp.573-579
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• 2002

Stoichiometric mullite ($3Al_2$$O_3$. $2SiO_2$) precursor sol has been prepared by sol-gel method. The effects of the precursor pH and sintering temperature on the synthesizing behavior and morphology of mullite have been studied. Mullite precursor sol was prepared by dissolution of aluminum nitrate enneahydrate (Al($NO_3$)$_3$.9H$_2O) into the mixture of silica sol. Precursor pH of the sols was controlled to acidic condition ($PH\leq$ 1~1.5) and to basic condition ($pH\geq$8.5~9). The synthesized aluminosilicate sols were formed under 20 MPa pressure after drying at $150^{\circ}C$ for 24 hours, and then sintered for 3hours in the temperature range of $1100~1600^{\circ}C$. From TGA/DTA analysis, total weight loss in the aluminosilicate gel of the acidic sample was (equation omitted) 56% and that of the basic sample was (equation omitted) 85%, indicating that the synthesizing temperature of mullite phase for acidic and basic samples was above $1200^{\circ}C$ and $1300^{\circ}C$, respectively. The morphologies of the synthesized mullite were fine and needle-like (or rod-like) for acidic sample, and granular for basic sample that has been sintered above $1300^{\circ}C$. It was found that the morphology of mullite particle was predominantly governed by precursor pH and sintering temperature.