US4980322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sinterable SI3 N4 powders containing sintering additives and a process for their preparation
Assignee: Bayer AG
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Filing: 1989-07-10
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Granted: 1990-12-25
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Expires: 2009-07-10
Abstract
Abstract Sinterable Si 3 N 4 powder containing Si 3 N 4 particles and sintering additives wherein Si 3 N 4 particles have an average particle size of less than 1 μm, contain no particle having a diameter greater than 100 μm, have a total content of metallic impurities less than 1000 ppm and an iron content of less than 200 ppm, and wherein the sintering additives are uniformly distributed throughout the powder is prepared by co-grinding pulverulent sintering additive and Si 3 N 4 containing less than 1000 ppm metallic impurities 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 21:11
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
103 words
A process for the preparation of sinterable Si 3 N 4 powder consisting essentially of Si 3 N 4 particles and sintering additives wherein the particles have an average particle size of less than 1 μm, with no particles having a diameter greater than 100 μm, have a total content of metallic impurities less than 1000 ppm and an iron content of less than 200 ppm, and wherein the sintering additives are uniformly distributed throughout the powder which consists essentially of co-grinding together in a spiral jet mill pulverulent sintering additive and Si 3 N 4 with less than 1000 ppm metallic impurities.
Claim 2
Dependent Claim
103 words
A process for the preparation of sinterable Si 3 N 4 powder consisting essentially of Si 3 N 4 particles and sintering additives wherein the particles have an average particle size of less than 1 μm, with no particles having a diameter greater than 100 μm, have a total content of metallic impurities less than 1000 ppm and an iron content of less than 200 ppm, and wherein the sintering additives are uniformly distributed throughout the powder which consists essentially of co-grinding together in a spiral jet mill pulverulent sintering additive and Si 3 N 4 with less than 1000 ppm metallic impurities.
Claim 3
Dependent Claim
17 words
A process according to claim 1 which comprises grinding in the presence of air, nitrogen or argon.
Claim 4
Dependent Claim
16 words
A process according to claim 2 wherein the gas pressure is from 2 to 10 bar.
Claim 5
Dependent Claim
24 words
A process according to claim 1, wherein the parts of the spiral jet mill contacting material being ground are fabricated from a non-metallic material.
Claim 6
Dependent Claim
35 words
A process according to claim 4 wherein the non-metallic material is a ceramic material chosen from the group consisting of B 4 C, Al 2 O 3 , SiC, and Si 3 N 4 .
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) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |