| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass sheet which has melting property equal to that of a general purpose float glass and nonetheless can be easily made into a high strength chemically strengthened glass and further has good chemical durability.SOLUTION: The glass sheet for chemical strengthening has a glass composition which contains, by mass%, SiOof 58 to 72, AlOof 1.5 to 6, NaO of 12 to 18, KO of 0 to 5, MgO of 1 to 8, CaO of 2 to 8, ZrOof 1.5 to 10 and in which NaO+KO =12 to 22, MgO+CaO =3 to 14, AlO+ZrO=3 to 15, AlO/ZrO= 0.15 to 2.7 by mass ratio of AlOand ZrO, (NaO+KO)/(AlO+ZrO) =1.1 to 3.0 by mass ratio of the total of NaO and KO and the total of AlOand ZrO. The glass sheet for chemical strengthening has a temperature at which viscosity become 10dPa s is 1520°C.SELECTED DRAWING: None |
