US4728582A
Expired / Lapsed
US
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Ceramic sliding element with aluminum oxide and silicon nitride members
Assignee: Feldmuehle AG
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Filing: 1986-08-05
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Granted: 1988-03-01
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Expires: 2006-08-05
Abstract
Abstract In a sliding element having first and second members in friction and/or sealing contact, the first member s made by sintering a ceramic mixture based on silicon nitride, the content of the silicon nitride phase and/or of the silicon nitride mixed crystal phase being at least 60 weight-percent and the second counter-element member being formed of a ceramic material based on aluminum oxide.
Inventors
- 👤 Hans-Jurgen Comans
- 👤 Ulrich Krohn
- 👤 Hans Jud
- 👤 Hans-Gerd Rittel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:41
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; F; F16; F16C; F16C33/00; F16C33/02; F16C33/04; F16C33/043; F16J; F16J15/00; F16J15/16; F16J15/34; F16J15/3496; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/131
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
68 words
In a sliding element of the type comprising first and second counter-element members in friction contact and/or sealing contact with each other the improvement comprising forming said first member of a silicon nitride based ceramic material having a content of silicon nitride phase and/or of silicon nitride mixed crystal phase of at least 60 wt.-%, and forming said counter-element second member of an aluminum oxide based ceramic material.
Claim 2
Dependent Claim
68 words
In a sliding element of the type comprising first and second counter-element members in friction contact and/or sealing contact with each other the improvement comprising forming said first member of a silicon nitride based ceramic material having a content of silicon nitride phase and/or of silicon nitride mixed crystal phase of at least 60 wt.-%, and forming said counter-element second member of an aluminum oxide based ceramic material.
Claim 3
Dependent Claim
16 words
The sliding element of claim 1 wherein said first member slides against said counter-element second member.
Claim 4
Dependent Claim
29 words
The sliding element of claim 1, wherein said first member has a content of the silicon nitride phase and/or silicon nitride mixed crystal phase of at least 80 wt.-%.
Claim 5
Dependent Claim
30 words
The sliding element of claim 1 wherein the silicon nitride phase is in the alpha or beta phase and the silicon nitride mixed crystal phase is in the beta' phase.
Claim 6
Dependent Claim
62 words
The sliding element of claim 1 wherein said silicon nitride ceramic material consists essentially of: 4.0 to 15 wt.-% yttrium oxide, which can be replaced entirely or in part by 1 to 5 wt.-% of MgO, 0 to 10 wt.-% silicon dioxide 0 to 10 wt.-% aluminum oxide 0 to 4 wt.-% iron oxide balance silicon nitride to make up 100 wt.-%.
Claim 7
Dependent Claim
25 words
The sliding element of claim 1 wherein said first member is a solid body made by pressure-less sintering of a shaped and precompacted powder mixture.
Claim 8
Dependent Claim
23 words
The sliding element of claim 1 wherein said first member is a solid body made by reaction sintering of a shaped powder mixture.
Claim 9
Dependent Claim
18 words
The sliding element of claim 1 wherein after sintering said first member is recompressed by hot isostatic pressing.
Claim 10
Dependent Claim
24 words
The sliding element of claim 1 characterized in that the first member and second counter-element member are elements of an axial friction ring seal.
Claim 11
Dependent Claim
24 words
The sliding element of claim 1 characterized in that the first member and second counter-element member are elements shaped as discs of a valve.
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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) | 1991-03-01 | 1991-08-31 | 1992-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-01 | 1995-08-31 | 1996-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-01 | 1999-08-31 | 2000-03-01 | $7700.00 | Window Closed / Lapsed |