We have investigated the crystallization mechanism of the lithium disilicate (Li2O-2SiO2, LSO) glass particles with different sizes by isothermal and non-isothermal processes. The LSO glass was fabricated by rapid quenching of melt. X-ray diffraction and differential scanning calorimetry measurements were performed. Different crystallization models of Johnson- Mehl-Avrami, modified Ozawa and Arrhenius were adopted to analyze the thermal measurements. The activation energy E and the Avrami exponent n, which describe a crystallization mechanism, were obtained for three different glass particle sizes. Values of E and n for the glass particle with size under 45 μm, 75~106 μm, and 125~150 μm, were 2.28 eV, 2.21 eV, 2.19 eV, and ~1.5 for the isothermal process, respectively. Those values for the non-isothermal process were 2.4 eV, 2.3 eV, 2.2 eV, and ~1.3, for the isothermal process, respectively. The obtained values of the crystallization parameters indicate that the crystallization occurs through the decreasing nucleation rate with a diffusion controlled growth, irrespective to the particle sizes. It is also concluded that the smaller glass particles require the higher heat absorption to be crystallized.

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in alack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditionsand mechanism of formation of gold color crystallization glaze containing Fe2O3(hematite), which is developed for gold colorsof ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and TiO2 phase in thebase of a crystallization glaze with a value of TiO2 of 6wt% confirmed by XRD and Raman Spectroscopy. When Fe2O3 wasused as a colorant for the gold color, the TiO2 peak became extinct and the intensity of the diopside peak was sharper. Feldsparof 60wt%, talc of 20wt% and limestone of 20wt% were used as the starting materials and these were tested using a threecomponent system. The best result of test was selected and extended to its vicinity as an experiment to determine TiO2 andFe2O3 contents. The glaze with TiO2 of 6wt% and Fe2O3 of 12wt% addition showed stable pyroxene based diopside crystalsand the development of gold color. This gold color was obtained with CIE-L*a*b* values of 51.27, 4.46, 16.15 (a grayishyellow brown color), which was gained using the following firing conditions: temperature increasing speed 5oC/min, holdingfor 1h at 1280oC, annealing speed 3oC/min till 1100oC, holding for 2h at 1100oC, and finally natural annealing.

세가지 다른 방법을 이용하여 형성시킨 비정질 실리콘(SiH4 a-Si, Si2H6 a-Si, Si+ implanted SiH4 a-Si)들에 대한 저온 결정화 기구의 차이를 고전적 이론인 Avrami 식(X=1-exptn, X=결정화 분율, t=열처리 시간, n=지수)을 이용하여 검토하였다. Silane으로 형성된 비정질 실리콘의 결정화 과정에서는 Avrami 식에서의 n의 값이 2.0을 나타내고 있어, 결정성장이 이차원적으로 이루어지면서 핵생성률이 시간에 따라 감소하고 있음을 알 수가 있었다. Si+ 이온 주입에 의하여 형성된 비정질 실리콘의 결정화에서는 3.0의 지수 값이 얻어지고 있어, 정상상태의 핵생성과 함께 2차원적인 결정 성장이 이루어지고 있었다. Disilane으로 형성된 비정질 실리콘에 대한 결정화에서는 2.8의 지수값이 얻어져, 정상상태의 핵 생성이 우세하게 일어나는 2차원적인 결정성장이 일어나고 있음을 알 수 있었다. 또한 TEM을 이용하여 시간에 따라 변하는 핵생성률을 조사하여, Avrami 식의 적용이 타당성 있음을 증명하였다. 마지막으로, 최종 입자의 크기가 열처리 온도에 크게 영향을 받고 있지 않음을 확인하였다.