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US5491116A
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Fine-grained glass-ceramics
Assignee: Corning Inc
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Filing: 1995-04-03
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Granted: 1996-02-13
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Expires: 2015-04-03
Abstract
Abstract A glass-ceramic article, such as an information disk substrate, and a method of making the article. The glass-ceramic has Mg-rich pyroxene and spinel-type predominate crystal phases and a composition at least 92% of which consists essentially of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO.
Inventors
- 👤 George H. Beall
- 👤 Linda R. Pinckney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:42
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0036; C03C10/0045
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
147 words
A glass-ceramic article exhibiting an MOR of at least about 15,000 psi, a Knoop hardness value of greater than at least about 760 KHN, a Young's modulus about 20×10 6 psi and a fracture toughness in excess of 1.0 MPa.m 1/2 , wherein the crystal phase assemblage is comprised predominately of magnesium containing crystals having a pyroxene structure represented by the formula (M 2 )(M 1 )Si 2 O 6 where M 2 has a coordination of 6-8 oxygen atoms and M 1 is octahedrally coordinated and spinel crystals which are uniformly dispersed within a highly siliceous residual glass matrix phase, the article having an overall composition at least 92 % of which consists essentially, expressed in terms of weight percent on the oxide basis, of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO.
Claim 2
Dependent Claim
147 words
A glass-ceramic article exhibiting an MOR of at least about 15,000 psi, a Knoop hardness value of greater than at least about 760 KHN, a Young's modulus about 20×10 6 psi and a fracture toughness in excess of 1.0 MPa.m 1/2 , wherein the crystal phase assemblage is comprised predominately of magnesium containing crystals having a pyroxene structure represented by the formula (M 2 )(M 1 )Si 2 O 6 where M 2 has a coordination of 6-8 oxygen atoms and M 1 is octahedrally coordinated and spinel crystals which are uniformly dispersed within a highly siliceous residual glass matrix phase, the article having an overall composition at least 92 % of which consists essentially, expressed in terms of weight percent on the oxide basis, of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO.
Claim 3
Dependent Claim
41 words
The glass-ceramic article according to claim 1 wherein the composition additionally contains a transition metal oxide selected from the group consisting of the oxides of Cu, Co, Fe, Mn, Cr, Sn and V, the oxide of Cr not exceeding about 1%.
Claim 4
Dependent Claim
18 words
A glass-ceramic article according to claim 1 wherein the pyroxene crystals exhibit dimensions less than about 1500 Å.
Claim 5
Dependent Claim
18 words
A glass-ceramic article according to claim 1 wherein the spinel crystals exhibit dimensions less than about 500 Å.
Claim 6
Dependent Claim
24 words
A glass-ceramic article according to claim 1 wherein the pyroxene crystal phase in the crystal phase assemblage is enstatite or an enstatite solid solution.
Claim 7
Dependent Claim
18 words
A glass-ceramic article according to claim 1 wherein the spinel crystals are primarily MgAl 2 O 4 .
Claim 8
Dependent Claim
44 words
A glass-ceramic article according to claim 1 wherein the composition consists essentially, expressed in terms of weight percent on the oxide basis, of 44-53% SiO 2 , 15-24% Al 2 O 3 , 15-22% MgO, 0-5% ZnO, 9-14% TiO 2 , and 0-3% NiO.
Claim 9
Dependent Claim
22 words
A glass-ceramic article according to claim 1 wherein the crystal phase assemblage further contains up to about 15% by weight titanate crystals.
Claim 10
Dependent Claim
31 words
A glass-ceramic article according to claim 1 wherein the Al 2 O 3 content in the composition does not exceed 25% unless NiO is present in an amount greater than 2%.
Claim 11
Independent Claim
185 words
A method for making a glass-ceramic article which comprises the steps of a. melting a batch for a glass composition at least 92% of which consists essentially, expressed in terms of weight percent on the oxide basis, of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO, b. heating the glass article to a temperature range of about 750°-850° C., c. maintaining the temperature for a time sufficient to cause the article to obtain a high degree of nucleation, d. heating the glass article to a temperature range about 900°-1100° C. and, e. maintaining the temperature for a time sufficient to cause the article to crystallize in situ forming a crystallized glass article which exhibits crystal phase assemblage comprised predominately of generally uniformly-sized magnesium containing crystals having a pyroxene structure represented by the formula (M 2 )(M 1 )Si 2 O 6 where M 2 has a coordination of 6-8 oxygen atoms and M 1 is octahedrally coordinated and spinel crystals which are uniformly dispersed within a highly siliceous residual glass matrix phase.
Claim 12
Independent Claim
185 words
A method for making a glass-ceramic article which comprises the steps of a. melting a batch for a glass composition at least 92% of which consists essentially, expressed in terms of weight percent on the oxide basis, of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO, b. heating the glass article to a temperature range of about 750°-850° C., c. maintaining the temperature for a time sufficient to cause the article to obtain a high degree of nucleation, d. heating the glass article to a temperature range about 900°-1100° C. and, e. maintaining the temperature for a time sufficient to cause the article to crystallize in situ forming a crystallized glass article which exhibits crystal phase assemblage comprised predominately of generally uniformly-sized magnesium containing crystals having a pyroxene structure represented by the formula (M 2 )(M 1 )Si 2 O 6 where M 2 has a coordination of 6-8 oxygen atoms and M 1 is octahedrally coordinated and spinel crystals which are uniformly dispersed within a highly siliceous residual glass matrix phase.
Claim 13
Dependent Claim
40 words
The method according to claim 10 wherein the glass composition additionally contains a transition metal oxide selected from the group consisting of the oxides of Cu, Co, Fe, Mn, Cr, Sn and V, the oxide Cr not exceeding about 1%.
Claim 14
Dependent Claim
19 words
The method according to claim 10 wherein the pyroxene crystals exhibit dimensions less than about 1500 Å in diameter.
Claim 15
Dependent Claim
19 words
The method according to claim 10 wherein the spinel crystals exhibit dimensions less than about 500 Å in diameter.
Claim 16
Dependent Claim
46 words
The method according to claim 10 wherein the period of time sufficient to cause the article to obtain a high degree of nucleation is at least 1 hour and the period of time sufficient to cause the article crystallize in situ ranges between about 1-4 hours.
Claim 17
Dependent Claim
34 words
The method according to claim 10 wherein the crystal phase assemblage contains primary crystal phases of enstatite or enstatite solid solution and MgAl 2 O 4 , and additionally contains a titanate crystal phase.
Claim 18
Dependent Claim
180 words
A rigid information disk for use in a magnetic memory storage device consisting essentially of a substrate with a coating of magnetic media on a surface thereof, wherein the substrate is comprised of a glass-ceramic material exhibiting an MOR of at least about 15,000 psi, a Knoop hardness value of greater than at least about 760 KHN, a Young's modulus about 20×10 6 psi and a fracture toughness in excess of 1.0 MPa.m 1/2 , wherein the crystal phase assemblage is comprised predominately of magnesium containing crystals having a pyroxene structure represented by the formula (M 2 )(M 1 )Si 2 O 6 where M 2 has a coordination of 6-8 oxygen atoms and M 1 is octahedrally coordinated and spinel crystals which are uniformly dispersed within a highly siliceous residual glass matrix phase, the substrate having an overall composition at least 92 % of which consists essentially, expressed in terms of weight percent on the oxide basis, of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO.
Claim 19
Dependent Claim
180 words
A rigid information disk for use in a magnetic memory storage device consisting essentially of a substrate with a coating of magnetic media on a surface thereof, wherein the substrate is comprised of a glass-ceramic material exhibiting an MOR of at least about 15,000 psi, a Knoop hardness value of greater than at least about 760 KHN, a Young's modulus about 20×10 6 psi and a fracture toughness in excess of 1.0 MPa.m 1/2 , wherein the crystal phase assemblage is comprised predominately of magnesium containing crystals having a pyroxene structure represented by the formula (M 2 )(M 1 )Si 2 O 6 where M 2 has a coordination of 6-8 oxygen atoms and M 1 is octahedrally coordinated and spinel crystals which are uniformly dispersed within a highly siliceous residual glass matrix phase, the substrate having an overall composition at least 92 % of which consists essentially, expressed in terms of weight percent on the oxide basis, of 35-60% SiO 2 , 10-30% Al 2 O 3 , 12-30% MgO, 0-10% ZnO, 5-20% TiO 2 , and 0-8% NiO.
Claim 20
Dependent Claim
42 words
A rigid information disk according to claim 16 wherein the substrate composition additionally contains a transition metal oxide selected from the group consisting of the oxides of Cu, Co, Fe, Mn, Cr, Sn and V, the oxide Cr not exceeding about 1%.
Claim 21
Dependent Claim
19 words
A rigid information disk according to claim 16 wherein the pyroxene crystals exhibit dimensions less than about 1500 Å.
Claim 22
Dependent Claim
19 words
A rigid information disk according to claim 16 wherein the spinel crystals exhibit dimensions less than about 500 Å.
Claim 23
Dependent Claim
25 words
A rigid information disk according to claim 16 wherein the pyroxene crystal phase in the crystal phase assemblage is enstatite or an enstatite solid solution.
Claim 24
Dependent Claim
19 words
A rigid information disk according to claim 16 wherein the spinel crystals are primarily MgAl 2 O 4 .
Claim 25
Dependent Claim
45 words
A rigid information disk according to claim 16 wherein the composition consists essentially, expressed in terms of weight percent on the oxide basis, of 44-53% SiO 2 , 15-24% Al 2 O 3 , 15-22% MgO, 0-5% ZnO, 9-14% TiO 2 , and 0-3% NiO.
Claim 26
Dependent Claim
23 words
A rigid information disk according to claim 16 wherein the crystal phase assemblage further contains up to about 15% by weight titanate crystals.
Claim 27
Dependent Claim
32 words
A rigid intimation disk according to claim 16 wherein the Al 2 O 3 content in the composition does not exceed 25% unless NiO is present in an amount greater than 2%.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-12 | 1999-08-14 | 2000-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-12 | 2003-08-14 | 2004-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-12 | 2007-08-14 | 2008-02-13 | $7700.00 | Window Closed / Lapsed |