| Summary: | 碩士 === 大同大學 === 材料工程學系(所) === 94 === Calcium aluminate glasses have good optical transmittance in the middle-infrared (3-5 μm region) and good mechanical properties. In order to apply the glasses in a severer environment, the IR properties must be improved. In this study, the glass was converted into glass-ceramics to enhance the mechanical properties at ambient and high temperature, CaO, Al2O3, MgO, and BaO were chosen as the main components of the glass. TiO2 and ZrO2 were added as the nucleating agents stimulate internal nucleation in the glass-ceramics.
According to the experimental results, the viscosity of the glass with addition of 8.26 wt% of TiO2 (T8) was slightly decreased and the glass can be internally nucleated. The glass-ceramic which was nucleated at the optimum nucleating temperature (755℃) for 8 h, followed by crystallizing at 850℃ for 4 h was full of Ca3Al2O6 phase. The above-mentioned T8 glass-ceramic showed only 25 % decrease in IR transmittance, 17 % increase in hardness, 61℃ increase in dilatometric softening point, and 19 % increase in Young’s modulus.
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