| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substrate which has high mechanical strength although it is not subjected to tempering treatment, a coefficient of linear thermal expansion nearly equal to that of a member for a motor, and high fracture toughness, and from which little alkali is eluted; and to provide a glass composition used for the same. SOLUTION: The glass composition contains glass components comprising, by weight, 45-75% SiO<SB>2,</SB>1-20% Al<SB>2</SB>O<SB>3</SB>, 0-8% B<SB>2</SB>O<SB>3</SB>, 65-90% of SiO<SB>2</SB>+Al<SB>2</SB>O<SB>3</SB>+B<SB>2</SB>O<SB>3</SB>, 7-20% in total of R<SB>2</SB>O (wherein, R is Li, Na or K),and 0.5-12% in total of R'O (wherein, R' is Mg, Ca, Sr, Ba, or Zn), and satisfies following formula: B<SB>2</SB>O<SB>3</SB>=0% or 0.1<R'O/B<SB>2</SB>O<SB>3</SB>≤3. COPYRIGHT: (C)2005,JPO&NCIPI
|
