초록 ▼

The chemically prestressable glass having a low bubble count and bubble size has the following composition in mol %, based on a total amount of oxides present, SiO.sub.2 from 63.0 to 67.5 mol %, Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %, Na.sub.2 O from 8.5 to 15.5 mol %, K.sub.2 O from 2.5 to 4.0 mol

The chemically prestressable glass having a low bubble count and bubble size has the following composition in mol %, based on a total amount of oxides present, SiO.sub.2 from 63.0 to 67.5 mol %, Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %, Na.sub.2 O from 8.5 to 15.5 mol %, K.sub.2 O from 2.5 to 4.0 mol %, MgO from 3.0 to 9.0 mol %, sum of CaO+SrO+BaO+ZnO from 0 to 2.5 mol %, TiO.sub.2 from 0.5 to 1.5 mol %, CeO.sub.2 from 0.02 to 0.5 mol %, As.sub.2 O.sub.3 from 0.02 to 0.35 mol %, SnO.sub.2 from 0. to 1.0 mol %, and F.sub.2 from 0.05 to 2.6 mol %, wherein the molar ratio [SiO.sub.2 ]/[Al.sub.2 O.sub.3 ] is 5.3 to 6.85, the molar ratio [Na.sub.2 O]/[K.sub.2 O] is 3.0 to 5.6, the molar ratio [Al.sub.2 O.sub.3 ]/[K.sub.2 O] is 2.8 to 3.6 and the molar ratio [Al.sub.2 O.sub.3 ]/[TiO.sub.2 +CeO.sub.2 ] is 7.6 to 18.5, but, when arsenic-free, SnO.sub.2 is from 0.02 to 1.0 mol % and F.sub.2 is from greater than 0.5 to 2.6 mol %. The invention also includes a safety glass and a hard disk for information storage made from this chemically prestressable glass.

대표청구항 ▼

[ What is claimed is new and is set forth in the following appended claims:] [1.] A chemically prestressable glass having a low bubble count and bubble size having the following composition in mol %, based on a total amount of oxides present:______________________________________ SiO.sub.2 from 63.0

[ What is claimed is new and is set forth in the following appended claims:] [1.] A chemically prestressable glass having a low bubble count and bubble size having the following composition in mol %, based on a total amount of oxides present:______________________________________ SiO.sub.2 from 63.0 to 67.5 mol %, Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %, Na.sub.2 O from 8.5 to 15.5 mol %, K.sub.2 O from 2.5 to 4.0 mol %, MgO from 3.0 to 9.0 mol %, .SIGMA.CaO+SrO+BaO+ZnO from 0 to 2.5 mol %, TiO.sub.2 from 0.5 to 1.5 mol %, CeO.sub.2 from 0.02 to 0.5 mol %, As.sub.2 O.sub.3 from 0.02 to 0.35 mol %, SnO.sub.2 from 0 to 1.0 mol %, and F.sub.2 from 0.05 to 2.6 mol %, ______________________________________ rein a molar ratio of the SiO.sub.2 to the Al.sub.2 O.sub.3 is between 5.3 and 6.85, a molar ratio of the Na.sub.2 O to the K.sub.2 O is between 3.0 and 5.6, a molar ratio of the Al.sub.2 O.sub.3 to K.sub.2 O is between 2.8 and 3.6 and a molar ratio of the Al.sub.2 O.sub.3 to a total amount of the TiO.sub.2 and the CeO.sub.2 is between 7.6 and 18.5.