US4397828A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stable liquid polymeric precursor to silicon nitride and process
Assignee: Massachusetts Institute of Technology
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Filing: 1981-11-16
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Granted: 1983-08-09
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Expires: 2001-11-16
Abstract
Abstract Stable, viscous polymers of silicon, nitrogen and hydrogen are formed by reacting a halosilane with ammonia in the presence of a solvent comprising an aliphatic ether, a chloromethane or mixtures thereof. After the solvent has been removed from the reaction product, the polymer can be poured into a container of desired shape and then can be sintered to form a uniform silicon nitride product.
Inventors
- 👤 Dietmar Seyferth
- 👤 Christian C. Prud'Homme
- 👤 Gary H. Wiseman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:45
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/589; C01; C01B; C01B21/00; C01B21/06; C01B21/068; C01B21/082; C01B21/087
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
90 words
A stable liquid, halide-free polymer of silicon, hydrogen and nitrogen prepared by reacting in the absence of oxygen and moisture a dihydrodihalosilane with ammonia in a solvent selected from the group consisting of an ether, a chloromethane and mixtures thereof to form the soluble liquid polymer and insoluble precipitated ammonium halide, separating the soluble liquid polymer from the insoluble ammonium halide in an oxygen and moisture-free atmosphere to obtain a soluble liquid polymer solution free of ammonium halide and subsequently recovering the polymer free of ammonium halide from the solvent.
Claim 2
Dependent Claim
90 words
A stable liquid, halide-free polymer of silicon, hydrogen and nitrogen prepared by reacting in the absence of oxygen and moisture a dihydrodihalosilane with ammonia in a solvent selected from the group consisting of an ether, a chloromethane and mixtures thereof to form the soluble liquid polymer and insoluble precipitated ammonium halide, separating the soluble liquid polymer from the insoluble ammonium halide in an oxygen and moisture-free atmosphere to obtain a soluble liquid polymer solution free of ammonium halide and subsequently recovering the polymer free of ammonium halide from the solvent.
Claim 3
Dependent Claim
10 words
The composition of claim 1 wherein the halosilane is dichlorosilane.
Claim 4
Dependent Claim
17 words
The composition of any one of claims 1 or 2 wherein the solvent is an aliphatic ether.
Claim 5
Dependent Claim
16 words
The composition of any one of claims 1 or 2 wherein the solvent is a chloromethane.
Claim 6
Dependent Claim
60 words
The process for preparing a three-dimensional article of a sintered silicon nitride which comprises introducing the liquid composition of claim 1 free of ammonium halide into a container of desired shape and pyrolyzing said composition at a temperature between about 500° C. and about 1200° C. an oxygen and moisture-free atmosphere, thereby to convert said polymer to sintered silicon nitride.
Claim 7
Dependent Claim
10 words
The process of claim 5 wherein said atmosphere is nitrogen.
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) | 1986-08-08 | 1987-02-07 | 1987-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-08 | 1991-02-07 | 1991-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-08 | 1995-02-07 | 1995-08-09 | $7700.00 | Window Closed / Lapsed |