| 摘要 |
PROBLEM TO BE SOLVED: To provide alkali free aluminoborosilicate glass having an optimized viscosity curve between 10<SP>4</SP>dPas and 10<SP>2</SP>dPas. SOLUTION: The aluminoborosilicate glass with 3.3×10<SP>-6</SP>/K coefficient of thermal expansion CTE comprises constituents (in wt.%) of SiO<SB>2</SB>of 58-70, Al<SB>2</SB>O<SB>3</SB>of 17-18, B<SB>2</SB>O<SB>3</SB>of 5-15, MgO of 0-9, CaO of 2-12, BaO of 0.1-5, SnO<SB>2</SB>of 0-1 and As<SB>2</SB>O<SB>3</SB>of 0-2 and contains no alkali oxide and strontium oxide except arbitrary impurities. The proportion (in wt.%) of SiO<SB>2</SB>.B<SB>2</SB>O<SB>3</SB>/Al<SB>2</SB>O<SB>3</SB>is between 32 and 38, and the mean gradient of the viscosity curve is less than or equal to -5.50×10<SP>-3</SP>dPas/K in the range between the common logarithm of the viscosities of 4 to 2. COPYRIGHT: (C)2008,JPO&INPIT |
