| 摘要 |
A transparent and colorless glass-ceramic containing crystals of beta -quartz and beta -eucryptite is obtained by heat-treating a glass essentially composed of 63-69 wt % of SiO2, 18-22 wt % of Al2O3, 3-5 wt % of Li2O, 1-3 wt % of MgO, 4-6 wt % of ZrO2, 0-2 wt % of ZnO, 0-2 wt % of P2O5, 0-2 wt % of Na2O, 0-2 wt % of BaO and 0.3-1 wt % of As2O3, with proviso that the proportion of ZrO2 to SiO2 is not lower than a specified level and that the molar ratio of Al2O3 to the total of Li2O, MgO and ZnO is within a specified range. The thermal expansion coefficient of this glass-ceramic is very close to zero over the range from room temperature to about 300 DEG C.
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