US4776866A
Expired / Lapsed
US
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Method for making extruded whisker-reinforced ceramic matrix composites
Assignee: Corning Glass Works
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Filing: 1987-04-23
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Granted: 1988-10-11
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Expires: 2007-04-23
Abstract
Abstract Whisker-reinforced ceramic matrix composites comprising a principal crystal phase selected from the group of anorthite, barium-stuffed cordierite, and mixed cordierite/anorthite are prepared by extrusion of extrudable ceramic batches comprising an extrusion vehicle and a solids component consisting essentially of inorganic whiskers and powdered glass, the glass being a thermally crystallizable glass containing an internal nucleant and capable of being consolidated at ambient pressures or above to a dense consolidated preform which may be converted to a substantially glass-free whisker-reinforced ceramic matrix composite by thermal treatment.
Inventors
- 👤 Shih-Lu Chen
- 👤 Kishor P. Gadkaree
- 👤 Joseph F. Mach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:20
CPC Classifications
C; C04; C04B; C04B14/00; C04B14/38; C03; C03C; C03C10/00; C03C10/0036; C03C10/0045; C03C14/00; C03C2214/00; C03C2214/06; C03C2214/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
255 words
A method for making a whisker-reinforced ceramic matrix composite article which comprises the steps of (a) compounding an extrusion batch comprising an extrusion vehicle component and a solids component, the solids component comprising 1-30% by weight of inorganic whiskers and 70-99% of a powdered thermally crystallizable RO-Al 2 O 3 -SiO 2 glass, wherein RO is an oxide selected from the group consisting of CaO, MgO and BaO, and the glass containing an internal nucleating agent and being of a composition crystallizable to yield anorthite, cordierite/anorthite, or barium-stuffed cordierite; (b) extruding the batch to provide a green ceramic preform; (c) heating the green ceramic preform to a consolidation temperature in the range between the softening point temperature of the glass and a temperature not exceeding 150° C. above the liquidus temperature of the glass, but below the deformation temperature of the preform, heating being at a rate sufficient to retain a glassy phase constituting at least 15 volume percent of the solids component of the preform at the consolidation temperature, to provide a consolidated preform; (d) cooling the consolidated preform to at least a temperature in the crystal nucleation range for the glass; (e) heating the consolidated preform at a temperature in the crystal nucleation range for the glass, and maintaining the preform at a temperature in the nucleation range for a time sufficient to provide a nucleated preform; and (f) heating the nucleated preform at a temperature in the crystallization range of the glass to crystallize the glass to anorthite, cordierite/anorthite or barium-stuffed cordierite.
Claim 2
Independent Claim
255 words
A method for making a whisker-reinforced ceramic matrix composite article which comprises the steps of (a) compounding an extrusion batch comprising an extrusion vehicle component and a solids component, the solids component comprising 1-30% by weight of inorganic whiskers and 70-99% of a powdered thermally crystallizable RO-Al 2 O 3 -SiO 2 glass, wherein RO is an oxide selected from the group consisting of CaO, MgO and BaO, and the glass containing an internal nucleating agent and being of a composition crystallizable to yield anorthite, cordierite/anorthite, or barium-stuffed cordierite; (b) extruding the batch to provide a green ceramic preform; (c) heating the green ceramic preform to a consolidation temperature in the range between the softening point temperature of the glass and a temperature not exceeding 150° C. above the liquidus temperature of the glass, but below the deformation temperature of the preform, heating being at a rate sufficient to retain a glassy phase constituting at least 15 volume percent of the solids component of the preform at the consolidation temperature, to provide a consolidated preform; (d) cooling the consolidated preform to at least a temperature in the crystal nucleation range for the glass; (e) heating the consolidated preform at a temperature in the crystal nucleation range for the glass, and maintaining the preform at a temperature in the nucleation range for a time sufficient to provide a nucleated preform; and (f) heating the nucleated preform at a temperature in the crystallization range of the glass to crystallize the glass to anorthite, cordierite/anorthite or barium-stuffed cordierite.
Claim 3
Dependent Claim
77 words
A method in accordance with claim 1 wherein the thermally crystallizable glass is a glass having a liquidus temperature not exceeding about 1600° C. selected from the group consisting of: (a) calcium aluminosilicate glasses comprising an internal nucleating agent and being fully crystallizable to anorthite; (b) barium-magnesium aluminosilicate glasses comprising an internal nucleating agent and being fully crystallizable to barium-stuffed cordierite; and (c) calcium-magnesium aluminosilicate glasses comprising an internal nucleating agent and being fully crystallizable to cordierite/anorthite.
Claim 4
Dependent Claim
29 words
A method in accordance with claim 2 wherein the preform is consolidated at a temperature in the range of about 1400°-1550° C. at atmospheric pressure in an inert atmosphere.
Claim 5
Dependent Claim
51 words
A method in accordance with claim 3 wherein the green ceramic preform is heated to the consolidation temperature at a heating rate in the range of about 3°-15° C. per minute and retains a glassy phase constituting 15-25 volume percent of the solids component of the preform at the consolidation temperature.
Claim 6
Dependent Claim
78 words
A method in accordance with claim 3 wherein the extrusion batch contains 5-25% by weight of SiC whiskers, wherein the thermally crystallizable glass consists essentially, in weight percent, of about 35-41% SiO 2 , 38-46% Al 2 O 3 , 16-20% CaO, 0.1-5% of nucleating agents selected from the group consisting of ZrO 2 and Nb 2 O 5 , and 0-2% As 2 O 3 , and wherein the green ceramic preform is consolidated at 1400°-1550° C.
Claim 7
Dependent Claim
42 words
A method in accordance with claim 5 wherein, after the green preform has been heated to provide a consolidated preform, the consolidated preform is cooled to the nucleation range for the consolidated thermally crystallizable glass without being further cooled to ambient temperature.
Claim 8
Dependent Claim
86 words
A method in accordance with claim 3 wherein the extrusion batch contains 5-25% by weight of SiC whiskers, wherein the thermally crystallizable glass is selected from among glasses consisting essentially, in weight percent, of about 41-45% SiO 2 , 35-38% Al 2 O 3 , 12-14% MgO, 5-7% BaO, and 0.01-5% of nucleating agents selected from the group consisting of ZrO 2 and Cr 2 O 3 , and 0-2% As 2 O 3 , and wherein the green ceramic preform is consolidated at 1425°-1525° C.
Claim 9
Dependent Claim
34 words
A method in accordance with claim 1 wherein the extrusion batch is extruded at an extrusion pressure in the range of about 500-2000 psi, and is heated to the consolidation temperature at atmospheric pressure.
Claim 10
Dependent Claim
38 words
A method in accordance with claim 1 wherein the green ceramic preform is heated to a consolidation temperature in the range from the liquidus temperature to about 50° C. above the liquidus temperature for the thermally crystallizable glass.
Claim 11
Dependent Claim
86 words
A method in accordance with claim 1 wherein the extrusion batch contains 5-25% by weight of SiC whiskers, wherein the thermally crystallizable glass is selected from among glasses consisting essentially, in weight percent, of about 37-50%, SiO 2 , 32-40% Al 2 O 3 , 8-15% CaO, 3-10% MgO, and 0.01-5% of nucleating agents selected from the group consisting of ZrO 2 and Nb 2 O 5 , and, 0-2% As 2 O 3 , and wherein the green ceramic preform is consolidated at 1400°-1500° C.
References Cited (Backward Citations)
US4464192A
Cited
US4615987A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-11 | 1992-04-11 | 1992-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-11 | 1996-04-11 | 1996-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-11 | 2000-04-11 | 2000-10-11 | $7700.00 | Window Closed / Lapsed |