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 03:37
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.
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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 |