Patent US3708438A successfully refreshed from Google Patents.
US3708438A
Expired / Lapsed
US
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Process for the preparation of lead containing piezoelectric powders
Assignee: WR Grace and Co Conn
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Filing: 1971-01-27
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Granted: 1973-01-02
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Expires: 1991-01-27
Abstract
Abstract A process for preparing lead oxide containing piezoelectric ceramic bodies capable of being sintered to greater than 90 percent of theoretical density at temperatures of 800 to 1,100* C by subjecting an intimate mixture of lead compounds with other materials to thermal dehydration or decomposition in a high temperature fluid energy mill.
Inventors
- 👤 N Levy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:03
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50; C01; C01G; C01G25/00; C01G25/006; C04B35/01; C04B35/46; C04B35/48; C04B35/51; C01P; C01P2002/00; C01P2002/30; C01P2002/34; C01P2004/00; C01P2004/60; C01P2004/62
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
123 words
A process for preparing lead zirconate, lead titanate, or lead titanate-zirconate ceramic bodies which comprises: a. subjecting powders, solutions, or slurries, of lead zirconium or titanium compounds selected from the group consisting of nitrates, carboxylates, hydroxides, and carbonates or mixtures thereof to thermal decomposition and dehydration in a fluid energy mill operated at inlet temperatures of 1,400* to 1,500* F and outlet temperatures of 700*to 1,100* F, in an atmosphere of steam or hot air, b. recovering the product ceramic powders the average particle size of which is less than one micron, c. cold pressing and sintering said powders in air at a temperature of 800* to 1,100* C to greater that 90 percent of theoretical density, and d. recovering the sintered product.
Claim 2
Dependent Claim
73 words
A process for preparing lead zirconate in the sub-micron size range which comprises: a. subjecting an aqueous solution of lead nitrate, carboxylate, hydroxide or carbonate and zirconium nitrate, carboxylate, hydroxide, or carbonate to thermal decomposition and dehydration in a fluid energy mill operated at inlet temperatures of 1,400* to 1,500* F and outlEt temperatures of 700* to 1,100* F, in an atmosphere of steam or hot air, and b. recovering the lead zirconate.
Claim 3
Dependent Claim
87 words
A process for preparing lead zirconate which comprises preparing an aqueous solution of lead nitrate and zirconium nitrate, subjecting said nitrate solution to thermal decomposition and dehydration in a fluid energy mill operated at inlet temperatures of 1,400* to 1,500* F and outlet temperatures of 700* to 1,100* F, recovering lead zirconate powder having an average particle size of less than 1 micron and sintering said lead zirconate powder in air at a temperature of 800* to 1,100* C to greater than 90 percent of theoretical density.
Claim 4
Dependent Claim
74 words
A process for preparing lead titanate in the sub-micron size range which comprises: a. subjecting an aqueous solution of lead nitrate, carboxylate, hydroxide, or carbonate and titanium nitrate, carboxylate, hydroxide, or carbonate to thermal decomposition and dehydration in a fluid energy mill operated at inlet temperatures of 1,400* to 1,500* F and outlet temperatures of 700* to 1,100* F in an atmosphere of steam or hot air, and b. recovering the lead titanate product.
Claim 5
Dependent Claim
88 words
A process for preparing lead titanate which comprises preparing an aqueous solution of lead nitrate and titanium nitrate, subjecting said nitrate solution to thermal decomposition and dehydration in a fluid energy mill operated at inlet temperatures of 1,400* to 1,500* F and outlet temperatures of 700* to 1,100* F., recovering lead titanate powder having an average particle size of less than 1 micron and sintering said lead titanate powder in air at a temperature of 800* C to 1,100* C to greater than 90 percent 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) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |