Patent US4300979A successfully refreshed from Google Patents.
US4300979A
Expired / Lapsed
US
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Growth of AlPO4 crystals
Assignee: AT&T Inc
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Filing: 1980-11-03
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Granted: 1981-11-17
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Expires: 2000-11-03
Abstract
Abstract AlPO4 crystals are isomorphic with quartz and are expected therefore to have several crystal orientations in which the elastic (piezoelectric) constants are relatively insensitive to temperature. The piezoelectric coupling coefficients of AlPO4 are approximately three times those of quartz. Hydrothermal growth techniques to date have been marginal, and all have employed H3PO4 as the hydrothermal solution. We describe using HCl as the hydrothermal solution and demonstrate the superiority of HCl from the standpoint of solubility and consequent crystal growth rate.
Inventors
- 👤 Ernest D. Kolb
- 👤 Robert A. Laudise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:17
CPC Classifications
C; C30; C30B; C30B7/00; C30B29/00; C30B29/10; C30B29/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
55 words
Process for growth of AlPO 4 crystals comprising disposing a seed in a hydrothermal medium comprising AlPO 4 solute in a solvent, maintaining the hydrothermal medium at a pressure and temperature sufficient to effect growth of AlPO 4 on the seed, the invention characterized in that the hydrothermal medium comprises an aqueous solution of HCl.
Claim 2
Dependent Claim
55 words
Process for growth of AlPO 4 crystals comprising disposing a seed in a hydrothermal medium comprising AlPO 4 solute in a solvent, maintaining the hydrothermal medium at a pressure and temperature sufficient to effect growth of AlPO 4 on the seed, the invention characterized in that the hydrothermal medium comprises an aqueous solution of HCl.
Claim 3
Dependent Claim
24 words
The process of claim 1 in which the hydrothermal medium is maintained at a temperature in the range of 150 to 400 degrees C.
Claim 4
Dependent Claim
30 words
The process of claim 2 in which the hydrothermal medium is contained in a pressure vessel and initially fills from 70 to 90 percent of the volume of the vessel.
Claim 5
Dependent Claim
34 words
The process of claim 3 in which nutrient material is added to the hydrothermal solution and growth is effected by the step of maintaining a temperature difference between the nutrient material and the seed.
Claim 6
Dependent Claim
19 words
The process of claim 4 in which the seed is maintained at a temperature higher than the nutrient material.
Claim 7
Dependent Claim
20 words
The process of claim 4 in which the temperature difference is in the range of 5 to 75 percent centigrade.
Claim 8
Dependent Claim
18 words
The process of claim 3 in which growth is effected by the step of heating the hydrothermal solution.
Claim 9
Dependent Claim
17 words
The process of claim 7 in which nutrient AlPO 4 material is added to the hydrothermal solution.
Claim 10
Dependent Claim
17 words
The process of claim 1 in which the aqueous solution contains 1.5 M to 8 M HCl.
Claim 11
Dependent Claim
23 words
The process of claim 1 in which the seed is an AlPO 4 crystal having an X-, Y-, Z- or z- crystallographic orientation.
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) | 1984-11-16 | 1985-05-18 | 1985-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-16 | 1989-05-18 | 1989-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-16 | 1993-05-18 | 1993-11-17 | $7700.00 | Window Closed / Lapsed |