| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substantially free from an alkali metal oxide, having low coefficient of thermal expansion, low density and high resistance (chemical resistance) against chemicals such as acids and alkalis, high strain point and excellent crack resistance, melting property and devitrification resistance. SOLUTION: The glass has the composition of, by mass%, 58 to 70% SiO2, 12 to 25% Al2O3, 9 to 15% B2O3, 0 to 1% MgO, 0 to 9% CaO, 0 to 6% SrO, 0 to 6% BaO, 0 to 5% ZnO, 0 to 5% ZrO2, 0 to 5% TiO2, 0 to 5% P2O5 satisfying SiO2+B2O3+P2O5>=65% and Al2O3/B2O3=1.2 to 2.0. The glass does not substantially contain alkali metal oxides. The glass has <=2.5 g/cm3 density, 26 to 40×10-7/ deg.C coefficient of thermal expansion at 30 to 380 deg.C and >=9.8 N crack resistance.
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