US4806295A
Expired / Lapsed
US
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Ceramic monolithic structure having an internal cavity contained therein and a method of preparing the same
Assignee: Osram Sylvania Inc
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Filing: 1988-03-02
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Granted: 1989-02-21
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Expires: 2008-03-02
Abstract
Abstract A method of preparing ceramic monolithic structures with an internal cavity and passageways is described. A thin sheet of a ceramic material is formed by spreading the material on a glass plate with a doctor blade. Individual sheets of the material are cut or punched to form predetermined holes, channels or various shapes therein. These individual sheets are then stacked to form a layered structure. A supporting media such as paraffin wax is injected into the holes and channels to completely fill them with the media. The layered structure is then pressed by unipressing and/or isostatic pressing followed by a prefiring step to remove the supporting media. Once the supporting media had been completely removed, the layered structure is then sintered to form a monolithic structure containing precise predetermined internal cavity and passageways.
Inventors
- 👤 Elizabeth A. Trickett
- 👤 Richard C. Assmus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:50
CPC Classifications
B; B28; B28B; B28B3/00; B28B1/00; B28B1/002; B28B7/00; B28B7/34; B28B7/342; B32; B32B; B32B18/00; C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/63; C04B35/638; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6567; C04B2235/66; C04B2235/661; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/50; C04B2237/62; C04B2237/70; C04B2237/704
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
186 words
A method for preparing a ceramic monolithic structure comprising the following steps: Step 1--forming a layered structure having a surface and a cavity contained therein by stacking individual sheets of a ceramic material having apertures in predetermined said sheets; stacking said individual sheets in a predetermined sequence to form a layered structure having a passageway and a cavity therein; said layered structure formed by said stacking of said individual sheets having a surface and a cavity connected to said surface thereof by said passageway; Step 2--filling said cavity and said passageway contained within said layered structure with a supporting media having a melting point greater than a pressing temperature obtained during a subsequent pressing step; Step 3--pressing the product from step 2 sufficiently to form a layered structure; Step 4--removing said supporting media from said cavity and said passageway of the product of step 3; Step 5--sintering the product from step 4 at a temperature sufficient to form a monolithic structure having a surface, said monolithic structure having a cavity contained therein and a passageway connecting the cavity to the said surface of said monolithic structure.
Claim 2
Independent Claim
186 words
A method for preparing a ceramic monolithic structure comprising the following steps: Step 1--forming a layered structure having a surface and a cavity contained therein by stacking individual sheets of a ceramic material having apertures in predetermined said sheets; stacking said individual sheets in a predetermined sequence to form a layered structure having a passageway and a cavity therein; said layered structure formed by said stacking of said individual sheets having a surface and a cavity connected to said surface thereof by said passageway; Step 2--filling said cavity and said passageway contained within said layered structure with a supporting media having a melting point greater than a pressing temperature obtained during a subsequent pressing step; Step 3--pressing the product from step 2 sufficiently to form a layered structure; Step 4--removing said supporting media from said cavity and said passageway of the product of step 3; Step 5--sintering the product from step 4 at a temperature sufficient to form a monolithic structure having a surface, said monolithic structure having a cavity contained therein and a passageway connecting the cavity to the said surface of said monolithic structure.
Claim 3
Dependent Claim
37 words
A method for preparing a ceramic monolithic structure in accordance with claim 1 wherein said ceramic material is selected from the group consisting of alumina, lanthana, yttria, magnesia, aluminum oxynitride, silicon nitride, magnesium aluminate and combinations thereof.
Claim 4
Dependent Claim
21 words
A method for preparing a ceramic monolithic structure in accordance with claim 1 wherein said supporting media comprises a paraffin wax.
Claim 5
Dependent Claim
25 words
A method for preparing a ceramic monolithic structure in accordance with claim 1 wherein said pressing comprises pressing by a uniaxial press followed by isopressing.
Claim 6
Dependent Claim
20 words
A method for preparing a ceramic monolithic structure in accordance with claim 1 wherein said apertures comprise holes and channels.
Claim 7
Dependent Claim
22 words
A method for preparing a ceramic monolithic structure in accordance with claim 1 wherein said pressing in step 3 comprises isostatic pressing.
Claim 8
Dependent Claim
37 words
A method for preparing a ceramic monolithic structure in accordance with claim 1 wherein said removing in step 4 comprises prefiring the product from step 3 at a temperature sufficient to remove said supporting media contained therein.
Claim 9
Independent Claim
202 words
A method for preparing a ceramic monolithic structure having an internal cavity and passageways comprising the following steps: Step 1--formulating a ceramic powder with suitable binders, plasticisers and thinners; Step 2--forming a large sheet from the product from step 1; Step 3--forming individual sheets from said large sheet from step 2; Step 4--forming apertures in predetermined individual sheets; Step 5--stacking said individual sheets from step 3 and said predetermined individual sheets from step 4 and aligning said apertures to form a layered structure having a cavity and passageways contained therein; Step 6--clamping the product from step 5 between templates; Step 7--inserting a supporting media into said cavity and said passageways of said layered structure to completely fill said cavity and said passageways with said media, said media being a solid at subsequent pressing temperatures and having a melting point slightly higher than subsequent pressing temperatures; Step 8--pressing by a uniaxial press the product frm step 7; Step 9--isopressing the product from step 8; Step 10--prefiring the product from step 9 at a temperature sufficient to remove said supporting media contained therein; and Step 11--sintering the product from step 10 to form a monolithic structure containing precise predetermined geometric cavity and passageways therein.
Claim 10
Independent Claim
202 words
A method for preparing a ceramic monolithic structure having an internal cavity and passageways comprising the following steps: Step 1--formulating a ceramic powder with suitable binders, plasticisers and thinners; Step 2--forming a large sheet from the product from step 1; Step 3--forming individual sheets from said large sheet from step 2; Step 4--forming apertures in predetermined individual sheets; Step 5--stacking said individual sheets from step 3 and said predetermined individual sheets from step 4 and aligning said apertures to form a layered structure having a cavity and passageways contained therein; Step 6--clamping the product from step 5 between templates; Step 7--inserting a supporting media into said cavity and said passageways of said layered structure to completely fill said cavity and said passageways with said media, said media being a solid at subsequent pressing temperatures and having a melting point slightly higher than subsequent pressing temperatures; Step 8--pressing by a uniaxial press the product frm step 7; Step 9--isopressing the product from step 8; Step 10--prefiring the product from step 9 at a temperature sufficient to remove said supporting media contained therein; and Step 11--sintering the product from step 10 to form a monolithic structure containing precise predetermined geometric cavity and passageways therein.
Claim 11
Dependent Claim
37 words
A method for preparing a ceramic monolithic structure in accordance with claim 8 wherein said ceramic material is selected from the group consisting of alumina, lanthana, yttria, magnesia, aluminum oxynitride, silicon nitride, magnesium aluminate, and combinations thereof.
Claim 12
Dependent Claim
21 words
A method for preparing a ceramic monolithic structure in accordance with claim 8 wherein said supporting media comprises a paraffin wax.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |