US4647547A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High temperature refractory of MgCr2 O4 matrix and unstabilized ZrO2 particles
Assignee: United States Department of Energy
•
Filing: 1985-12-10
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Granted: 1987-03-03
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Expires: 2005-12-10
Abstract
Abstract A high chromia refractory composite has been developed with improved thermal shock resistance and containing about 5-30 wt. % of unstabilized ZrO2 having a temperature-dependent phase change resulting in large expansion mismatch between the ZrO2 and the chromia matrix which causes microcracks to form during cooling in the high chromia matrix. The particle size preferably is primarily between about 0.6-5 microns and particularly below about 3 microns with an average size in the order of 1.2-1.8 microns.
Inventors
- 👤 Jitendra P. Singh
- 👤 Jawana J. James
- 👤 John J. Picciolo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:35
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/03; C04B35/04; C04B35/043; C04B35/0435; C04B35/047; C04B35/0476; C04B35/42
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
41 words
A sintered refractory product consisting essentially of MgCr 2 O 4 as a matrix and about 5-30 wt. % unstabilized ZrO 2 formed from particlcs of ZrO 2 having an average size below about 5 microns and above about 0.6 microns.
Claim 2
Dependent Claim
41 words
A sintered refractory product consisting essentially of MgCr 2 O 4 as a matrix and about 5-30 wt. % unstabilized ZrO 2 formed from particlcs of ZrO 2 having an average size below about 5 microns and above about 0.6 microns.
Claim 3
Dependent Claim
21 words
The refractory product of claim 1 wherein the particles of ZrO 2 have a size distribution primarily below about 2 microns.
Claim 4
Dependent Claim
15 words
The refractory product of claim 2 containing microcracks adjacent the particles of ZrO 2 .
Claim 5
Dependent Claim
30 words
The refractory product of claim 1 consisting essentially of said MgCr 2 O 4 , ZrO 2 wherein the particles of ZrO 2 range in size between about 0.6-3 microns.
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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) | 1990-03-02 | 1990-09-01 | 1991-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-02 | 1994-09-01 | 1995-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-02 | 1998-09-01 | 1999-03-03 | $7700.00 | Window Closed / Lapsed |