Glass-ceramic composition for recording disk substrate
AssigneeMinolta Co., Ltd.
InventorsHideki Nagata, Toshiharu Mori, Hiroshi Yuki, Hideki Kawai, Akira Sugimoto, Kazuhiko Ishimaru
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Abstract
A glass ceramics composition for recording disk substrate contains, essentially, expressed in terms of weight percent on the oxide basis, from 50.5 to 56 wt % of SiO2, from 10 to 30 wt % of Al2O3, from 10 to 30 wt % of MgO, and from 4.2 to 10.6 wt % of TiO2.
Claims24
A glass ceramics composition for recording disk substrate consisting essentially, expressed in terms of weight percent on an oxide basis, of
- from 50.5 to 56 wt % of SiO2,
- from 10 to 30 wt % of Al2O3,
- from 10 to 30 wt % of MgO, and
- from 4.2 to 10.6 wt % of TiO2.
A glass ceramic recording disk substrate, wherein the glass ceramic is prepared from a composition which consists essentially, expressed in terms of weight percent on an oxide basis, of
- from 50.5 to 56 wt % of SiO2,
- from 10 to 30 wt % of Al2O3,
- from 10 to 30 wt % of MgO, and
- from 4.2 to 10.6 wt % of TiO2.
Dependencies are inferred from the claim text.