Glass-ceramic composition for recording disk substrate

• US 6,593,257 B1
• Filed: 07/05/2000
• Issued: 07/15/2003
• Est. Priority Date: 07/06/1999
• Status: Expired due to Fees

• Current Assignee: Hoya Corporation
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Kawai, Hideki, Nagata, Hideki, Ishimaru, Kazuhiko, Mori, Toshiharu, Yuki, Hiroshi
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US09/610,337
• Time in Patent Office: 1,105 Days
• Field of Search: 501/4, 501/5, 428/694.ST, 428/694.SG
• US Class Current: 501/4
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: G11B 5/73921 Glass or ceramic substrates

Abstract

A glass ceramics composition for recording disk substrate consists essentially, expressed in terms of weight percent on the oxide basis, of from 65 to 80 wt % of SiO₂, from 3 to 15 wt % of Al₂O₃, from 3 to 15 wt % of Li₂O, from 0.2 to 5 wt % of P₂O₅, and from 0.1 to 15 wt % of ZrO₂, wherein a value of ZrO₂/P₂O₅ is within a range from 1.1 to 8.5, expressed in terms of weight percent on the oxide basis.

Claims

1. A glass ceramics composition for recording disk substrate consisting essentially, expressed in terms of weight percent on an oxide basis, of

from 65 to 80 wt % of SiO₂,

from 9.5 to 15 wt % of Al₂O₃,

from 3 to 15 wt % of Li₂O,

from 0.2 to 5 wt % of P₂O₅, and

from 0.22 to 15 wt % of ZrO₂,

wherein a value of ZrO₂/P₂O₅ is within a range from 1.1 to 8.5, expressed in terms of weight percent on the oxide basis.

2. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of CaO.

3. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of K₂O.

4. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of Sb₂O₃.

5. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists.essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 15 wt % of B₂O₃.

6. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 12 wt % of MgO.

7. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of BaO.

8. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of ZnO.

9. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of Nb₂O₅.

10. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of Ta₂O₅.

11. A glass ceramics composition as claimed in claim 1, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of La₂O₃.

12. A glass ceramic recording disk substrate, wherein the glass ceramic is prepared from a composition consisting essentially, expressed in terms of weight percent on the oxide basis, of

from 65 to 80 wt % of SiO₂,

from 9.5 to 15 wt % of Al₂O₃,

from 3 to 15 wt % of Li₂O,

from 0.2 to 5 wt % of P₂O₅, and from 0.22 to 15 wt % of ZrO₂,

wherein a value of ZrO₂/P₂O₅ is within a range from 1.1 to 8.5, expressed in terms of weight percent on the oxide basis.

13. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of CaO.

14. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of K₂O.

15. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of Sb₂O₃.

16. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 15 wt % of B₂O₃.

17. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 12 wt % of MgO.

18. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of BaO.

19. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of ZnO.

20. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of Nb₂O₅.

21. A recording disk substrate as claimed in claim 12, wherein said glass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of Ta₂O₅.

22. A recording disk substrate as claimed in claim 12, wherein said lass ceramic composition further consists essentially, expressed in terms of weight percent on the oxide basis, of

from 0.1 to 5 wt % of La₂O₃.

23. A recording disk substrate as claimed in claim 12, wherein the glass ceramic includes crystalline phase of quartz.

24. A recording disk substrate as claimed in claim 12, wherein the glass ceramic includes crystalline phase of lithium disilicate.

25. A recording disk substrate as claimed in claim 12, wherein the recording disk substrate contains a lithium disilicate as a main crystalline phase or subordinate crystalline phase.