US4374897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chromium oxide-based sintered bodies and process for production thereof
Assignee: Nippon Chemical Industrial Co Ltd
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Filing: 1981-03-04
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Granted: 1983-02-22
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Expires: 2001-03-04
Abstract
Abstract A highly densified chromium oxide-based sintered body is produced by heating a powder mixture of chromium sesquioxide and at least one substance selected from silica, zirconia and zircon in a carbon powder. The highly densified chromium oxide-based sintered body has excellent resistance to corrosion and excellent heat shock resistance, and thus is useful as a refractory material.
Inventors
- 👤 Akira Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:38
CPC Classifications
C; C03; C03B; C03B5/00; C03B5/16; C03B5/42; C03B5/43; C04; C04B; C04B35/00; C04B35/01; C04B35/12; C04B35/14; C04B35/48; C04B35/481; C04B35/486
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
79 words
A highly densified chromium oxide-based sintered body having a relative density of at least 90% and a linear thermal expansion coefficient of from 2.5×10 -6 /°C. to 7.2×10 -6 /°C. produced by heating a compact consisting of chromium oxide and at least one substance selected from silica (SiO 2 ), zirconia (ZrO 2 ), and zircon (ZrSiO 4 ) in a carbon reduction atmosphere wherein the surface of the compact is converted to a carbide during the heating period.
Claim 2
Dependent Claim
79 words
A highly densified chromium oxide-based sintered body having a relative density of at least 90% and a linear thermal expansion coefficient of from 2.5×10 -6 /°C. to 7.2×10 -6 /°C. produced by heating a compact consisting of chromium oxide and at least one substance selected from silica (SiO 2 ), zirconia (ZrO 2 ), and zircon (ZrSiO 4 ) in a carbon reduction atmosphere wherein the surface of the compact is converted to a carbide during the heating period.
Claim 3
Dependent Claim
22 words
A highly densified chromium oxide-based sintered body as in claim 1 wherein the chromium sesquioxide content is at least 20% by weight.
Claim 4
Dependent Claim
33 words
A highly densified chromium oxide-based sintered body as in claim 1, wherein the chromium oxide content is from 20 to 99% by weight of the sintered body, as Cr 2 O 3 .
Claim 5
Dependent Claim
17 words
A highly densified chromium oxide-based sintered body as in claim 1, wherein the carbide is chromium carbide.
Claim 6
Dependent Claim
22 words
A highly densified chromium oxide-based sintered body as in claim 4, wherein the at least one substance is silica (SiO 2 ).
Claim 7
Dependent Claim
22 words
A highly densified chromium oxide-based sintered body as in claim 4, wherein the at least one substance is zirconia (ZrO 2 ).
Claim 8
Dependent Claim
22 words
A highly densified chromium oxide-based sintered body as in claim 4, wherein the at least one substance is zircon (ZrSiO 4 ).
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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) | 1986-02-21 | 1986-08-23 | 1987-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-21 | 1990-08-23 | 1991-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-21 | 1994-08-23 | 1995-02-22 | $7700.00 | Window Closed / Lapsed |