Patent US4888310A successfully refreshed from Google Patents.
US4888310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulverulent silicon nitride composition including oxidized silicon carbide whiskers
Assignee: Battelle Memorial Institute Inc
•
Filing: 1987-11-24
•
Granted: 1989-12-19
•
Expires: 2007-11-24
Abstract
Abstract Reinforcing Si 3 N 4 ceramics with preoxidized SiC whiskers improves flexural strength and WEIBULL modulus over that of comparable bulk Si 3 N 4 ceramics or Si 3 N 4 ceramics reinforced with neat SiC whiskers. Hot isostatic pressing further improves the physical properties of said ceramics.
Inventors
- 👤 Dominique Richon
- 👤 Olivier de Pous
- 👤 Pierre Fontaine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:31
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/6455; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/71; C04B35/78; C04B35/80; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/2933; Y10T428/2938; Y10T428/294; Y10T428/2942; Y10T428/2949
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
68 words
A silicon nitride pulverulent composition for making whisker reinforced sintered articles by high temperature sintering and/or hot isostatic pressing, this composition consisting essentially of in admixture: (a) Si 3 N 4 powder; (b) from 2 to 15% by volume of SiC whiskers; (c) a metal oxide densifying aid; characterized in that, the SiC whiskers are superficially oxidized sufficiently to form a 2-20 nm layer of SiO 2 .
Claim 2
Dependent Claim
68 words
A silicon nitride pulverulent composition for making whisker reinforced sintered articles by high temperature sintering and/or hot isostatic pressing, this composition consisting essentially of in admixture: (a) Si 3 N 4 powder; (b) from 2 to 15% by volume of SiC whiskers; (c) a metal oxide densifying aid; characterized in that, the SiC whiskers are superficially oxidized sufficiently to form a 2-20 nm layer of SiO 2 .
Claim 3
Dependent Claim
41 words
The composition of claim 1, in which the Si 3 N 4 is α-Si 3 N 4 powder in grains of 0.7-0.8 μm mesh size, a surface area of 6-7 m 2 /g and an oxygen content of 0.8-1.2% by weight.
Claim 4
Dependent Claim
18 words
The composition of claim 1, in which the average length of the SiC whiskers is about 30-50 μm.
Claim 5
Dependent Claim
29 words
The composition of claim 1, in which the metal oxide densifying aid is selected from the group consisting of Al 2 O 3 , MgO, yttria and mixtures thereof.
Claim 6
Dependent Claim
15 words
The composition of claim 1, wherein the densifying aid consists of 5-12% b.w. of MgO.
References Cited (Backward Citations)
JPS5895648A
Cited
JPS5930770A
Cited
JPS59137366A
Cited
JPS59152270A
Cited
JPS59156972A
Cited
US4481179A
Cited
US4543345A
Cited
JPS61111908A
Cited
JPS61141678A
Cited
EP0188270A2
Cited
JPS61256985A
Cited
US4806428A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-18 | 1993-06-19 | 1993-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-18 | 1997-06-19 | 1997-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-18 | 2001-06-19 | 2001-12-19 | $7700.00 | Window Closed / Lapsed |