Patent US4925608A successfully refreshed from Google Patents.
US4925608A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Joining of SiC parts by polishing and hipping
Assignee: Saint Gobain Abrasives Inc
•
Filing: 1988-09-27
•
Granted: 1990-05-15
•
Expires: 2008-09-27
Abstract
Abstract A method of joining two pre-sintered pieces of silicon carbide is disclosed. It entails polishing the surfaces to be joined to a mirror-finish, fitting the polished surfaces together to form a composite structure, and then subjecting the composite structure to hot isostatic pressing under conditions which are sufficient to form a joint which is essentially indistinguishable from the original silicon carbide pieces.
Inventors
- 👤 Guilio A. Rossi
- 👤 Paul J. Pelletier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:56
CPC Classifications
C; C04; C04B; C04B37/00; C04B37/001; B; B82; B82Y; B82Y30/00; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6567; C04B2235/658; C04B2235/6582; C04B2235/6586; C04B2235/70; C04B2235/72; C04B2235/728; C04B2235/74; C04B2235/78; C04B2235/781; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/36; C04B2237/363; C04B2237/365; C04B2237/50; C04B2237/52; C04B2237/56; C04B2237/568
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
88 words
A method of joining two pre-densified predominantly beta-silicon carbide pieces which comprises (i) polishing a surface of each silicon carbide piece to a mirror-like condition, (ii) fitting the polished surfaces to each other to form a partially bonded composite structure, and (iii) subjecting the structure to hot isostatic pressing conditions at a pressure of at least about 22,000 psi which preclude the entrance of any species into the joint and which are sufficient to form a uniform joint which is essentially indistinguishable from the original silicon carbide pieces.
Claim 2
Independent Claim
88 words
A method of joining two pre-densified predominantly beta-silicon carbide pieces which comprises (i) polishing a surface of each silicon carbide piece to a mirror-like condition, (ii) fitting the polished surfaces to each other to form a partially bonded composite structure, and (iii) subjecting the structure to hot isostatic pressing conditions at a pressure of at least about 22,000 psi which preclude the entrance of any species into the joint and which are sufficient to form a uniform joint which is essentially indistinguishable from the original silicon carbide pieces.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the silicon carbide pieces have an initial density of at least about 85% of theoretical.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the silicon carbide pieces have an initial density of at least about 90% of theoretical.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the silicon carbide pieces have an initial density of about 95% or more of theoretical.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the polished surfaces are smooth to within 60 nanometers.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein the polished surfaces are smooth to within 30 nanometers.
Claim 8
Dependent Claim
20 words
The method of claim 1 wherein the hot isostatic pressing conditions comprise placing the composite structure in a tantalum can.
Claim 9
Dependent Claim
27 words
The method of claim 1 wherein the hot isostatic pressing conditions comprise placing the composite structure in a glass or a material forming a glass upon heating.
Claim 10
Dependent Claim
23 words
The method of claim 1 wherein, prior to the hot isostatic pressing, the joint is encapsulated with a sealed layer of silicon carbide.
Claim 11
Dependent Claim
17 words
The method of claim 9 wherein the sealed silicon carbide layer is formed by chemical vapor deposition.
Claim 12
Independent Claim
39 words
The method of claim wherein the hot isostatic pressing conditions comprise a temperature of at least about 1,700 C. and a pressure of at least about 22,000 psi, for a time of at least about 30 minutes at temperature.
Claim 13
Dependent Claim
31 words
The method of claim 1 wherein the hot isostatic pressing conditions comprise at least about 1,800 C. and at least about 25,000 psi, for at least about 45 minutes at temperature.
Claim 14
Dependent Claim
29 words
The method of claim 1 wherein the hot isostatic pressing conditions comprise at least about 1,900 C. and at least about 30,000 psi, for about one hour at temperature.
Claim 15
Dependent Claim
32 words
The method of claim 1 wherein after fitting the pieces together and before the hot isostatic pressing the composite structure is subjected to a heating operation to improve the initial partial bond.
Claim 16
Dependent Claim
21 words
The method of claim 14 wherein the heating is at about 2,100 C. for about 1 hour in an inert atmosphere.
Claim 17
Dependent Claim
33 words
The method of claim 1 wherein the silicon carbide pieces are each prepared from beta-silicon carbide and at least some of the beta form has been converted to the alpha form during pre-densification.
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) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |