| 摘要 |
An alkali-free glass consists essentially of, in mass percent, 58-70 % SiO2, 10-19 % Al2O3, 6.5-15 % B2O3, 0-2 % MgO, 3-12 % CaO, 0.1-5 % BaO, 0-4 % SrO, 0.1-6 % BaO+SrO, 0-5 % ZnO, 5-15 % MgO+CaO+BaO+SrO+ZnO, 0-5 % ZrO2, 0-5 % TiO2, and 0-5 % P2O5. The alkali-free glass contains substantially no alkali metal oxide and has a density of 2.45g/cm<3> or less, an average coefficient of thermal expansion of 25 x 10<-7>/ DEG C - 36 x 10<-7>/ DEG C within a temperature range between 30 and 380 DEG C, and a strain point not lower than 640 DEG C. |
