US4845060A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sinterable Si3 N4 powder and a process for its preparation
Assignee: Bayer AG
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Filing: 1987-05-22
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Granted: 1989-07-04
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Expires: 2007-05-22
Abstract
Abstract Sinterable Si 3 N 4 powder having an average particle size of less than 1 μm, wherein no individual particle has a diameter greater than 100 μm, the total content of metallic impurities of the powder is less than 1000 ppm and the iron content is less than 200 ppm is produced by grinding agglomerated Si 3 N 4 in a spiral jet mill.
Inventors
- 👤 Ulrike Wickel
- 👤 Gerhard Franz
- 👤 Benno Laubach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:41
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/068; C01B21/0687; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C01P; C01P2004/00; C01P2004/50; C01P2004/60; C01P2004/62; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
65 words
A process for producing sinterable Si 3 N 4 powder having an average particle size of less than 1 μm, the total content of metallic impurities of the powder is less than 1000 ppm and the iron content is less than 200 ppm which consists essentially of grinding agglomerated Si 3 N 4 containing less than 1000 ppm metallic impurities in a spiral jet mill.
Claim 2
Dependent Claim
65 words
A process for producing sinterable Si 3 N 4 powder having an average particle size of less than 1 μm, the total content of metallic impurities of the powder is less than 1000 ppm and the iron content is less than 200 ppm which consists essentially of grinding agglomerated Si 3 N 4 containing less than 1000 ppm metallic impurities in a spiral jet mill.
Claim 3
Dependent Claim
26 words
A process according to claim 1 wherein after grinding the ground powder is deposited on a filter bag of needled felt, plastic fabric or plastic-coated fabric.
Claim 4
Dependent Claim
18 words
A process according to claim 1 which comprises grinding in the presence of air, nitrogen or argon gas.
Claim 5
Dependent Claim
16 words
A process according to claim 3 wherein the gas pressure is from 2 to 10 bar.
Claim 6
Dependent Claim
25 words
A process according to claim 1 wherein the parts of the spiral jet mill contacting Si 3 N 4 are fabricated from a non-metallic material.
Claim 7
Dependent Claim
17 words
A process according to claim 5 wherein the non-metallic material is a synthetic or a ceramic material.
Claim 8
Dependent Claim
36 words
A process according to claim 5 wherein the non-metallic material is a ceramic material chosen from the group consisting of B 4 C, Al 2 O 3 , SiC, Si 3 N 4 and mixtures thereof.
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) | 1992-07-03 | 1993-01-02 | 1993-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-03 | 1997-01-02 | 1997-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-03 | 2001-01-02 | 2001-07-04 | $7700.00 | Window Closed / Lapsed |