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US5484750A
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Transparent polycrystalline garnets
Assignee: General Electric Co
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Filing: 1994-08-10
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Granted: 1996-01-16
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Expires: 2014-08-10
Abstract
Abstract Transparent, polycrystalline garnet bodies having desirable properties for use as laser material, luminescent x-ray scintillator materials and other uses are produced by mixing a chloride source solution of the desired cations with a basic ammonium solution to produce a precipitate having a substantially uniform composition which can be further processed to provide the desired transparent body. This precipitate is separated from the solution, dried, thermally decomposed at a temperature in the range from 700° to 1,000° C., pressed to form a compact, isostatically pressed at up to 60,000 psi to provide a green, unsintered compact having a density in the vicinity of 55% of theoretic density. That green compact is then sintered in oxygen at a temperature between 1,400° and 1,700° C. to produce the desired transparent body. Alternatively, the compact may be sintered in oxygen at temperatures in the range from about 1,400° to about 1,600° C. to a closed pore stage and then hot isostatically pressed at high pressure to provide the desired transparent body.
Inventors
- 👤 Charles D. Greskovich
- 👤 William P. Minnear
- 👤 Chester R. O'Clair
- 👤 Erdogan O. Gurmen
- 👤 Robert J. Riedner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:27
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C01; C01G; C01G15/00; C04B35/50; C04B35/622; C04B35/64; C04B35/645; C04B35/6455; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7701; C09K11/7708; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3224; C04B2235/3229; C04B2235/3231; C04B2235/3241; C04B2235/3286; C04B2235/44; C04B2235/449; C04B2235/60; C04B2235/604; C04B2235/608; C04B2235/65; C04B2235/656; C04B2235/6562; C04B2235/658; C04B2235/6587; C04B2235/66; C04B2235/661; C04B2235/662; C04B2235/70; C04B2235/74; C04B2235/76; C04B2235/762; C04B2235/764; C04B2235/77; C04B2235/80; C04B2235/81; C04B2235/96; C04B2235/9646; C04B2235/9653
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
68 words
A transparent polycrystalline body in non-powdered form comprising: between 0.554 and 0.625 mole fraction gallium oxide; between 0.375 and 0.442 mole fraction gadolinium oxide; between 0.001 and 0.004 mole fraction of chromium oxide wherein the chromium is present in a 3+ oxidation state; said body having a density of at least 99.9% of theoretical density; and the individual grains of said polycrystalline body having cubic garnet crystal structures.
Claim 2
Dependent Claim
68 words
A transparent polycrystalline body in non-powdered form comprising: between 0.554 and 0.625 mole fraction gallium oxide; between 0.375 and 0.442 mole fraction gadolinium oxide; between 0.001 and 0.004 mole fraction of chromium oxide wherein the chromium is present in a 3+ oxidation state; said body having a density of at least 99.9% of theoretical density; and the individual grains of said polycrystalline body having cubic garnet crystal structures.
Claim 3
Dependent Claim
68 words
A transparent polycrystalline body in non-powdered form comprising individual single crystalline grains, each of said grains having: a cubic garnet crystal structure, and a chemical composition A x B y-z C z O 12 ; where 3≦x≦3.536, 4.344≦y≦5, 0.008≦z≦0.120, A is gadolinium, B is gallium, and C is chromium ions in a 3+ oxidation state; and said body having a density of at least 99.9% of theoretical density.
Claim 4
Dependent Claim
68 words
A transparent polycrystalline body in non-powdered form comprising individual single crystalline grains, each of said grains having: a cubic garnet crystal structure, and a chemical composition A x B y-z C z O 12 ; where 3≦x≦3.536, 4.344≦y≦5, 0.008≦z≦0.120, A is gadolinium, B is gallium, and C is chromium ions in a 3+ oxidation state; and said body having a density of at least 99.9% of theoretical density.
Claim 5
Dependent Claim
111 words
A transparent polycrystalline body in non-powdered form in which: the individual single crystalline grains comprising said polycrystalline body have: cubic garnet crystal structures, and a chemical composition A x B y-z C z O 12 ; where 3≦x≦3.536 4.344≦y≦5, 0.008≦z≦0.120, A is a rare earth or yttrium cation in a 3+ oxidation state or mixture thereof and may contain an effective activating amount of Ce or Nd in a 3+ oxidation state; B is a gallium, aluminum or rare earth cation in a 3+ oxidation state; and C is a Cr activator cation in the 3+ oxidation state; and said body has a density of at least 99.9% of theoretical density.
Claim 6
Dependent Claim
111 words
A transparent polycrystalline body in non-powdered form in which: the individual single crystalline grains comprising said polycrystalline body have: cubic garnet crystal structures, and a chemical composition A x B y-z C z O 12 ; where 3≦x≦3.536 4.344≦y≦5, 0.008≦z≦0.120, A is a rare earth or yttrium cation in a 3+ oxidation state or mixture thereof and may contain an effective activating amount of Ce or Nd in a 3+ oxidation state; B is a gallium, aluminum or rare earth cation in a 3+ oxidation state; and C is a Cr activator cation in the 3+ oxidation state; and said body has a density of at least 99.9% of theoretical density.
References Cited (Backward Citations)
FR30170E
Cited
US3550033A
Cited
US3767745A
Cited
US4029755A
Cited
US4350559A
Cited
US4350558A
Cited
US4525628A
Cited
US4747973A
Cited
US4802180A
Cited
EP0297269A1
Cited
US4987575A
Cited
EP0370824A1
Cited
EP0399665A1
Cited
US5256242A
Cited
US4980320A
Cited
US5057692A
Cited
US5318722A
Cited
US5100598A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-15 | 1999-07-17 | 2000-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-15 | 2003-07-17 | 2004-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-15 | 2007-07-17 | 2008-01-16 | $7700.00 | Window Closed / Lapsed |