US3974108A
Expired / Lapsed
US
⏱️ 0.0 years remaining
LaCrO3 electrodes and method of manufacture
Assignee: General Refractories Co
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Filing: 1974-11-19
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Granted: 1976-08-10
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Expires: 1994-11-19
Abstract
Abstract A technique of forming electrodes for magneto-hydrodynamic generators having the composition (La 1 -x Y.sbsb.x ) CrO 3 where Y is strontium, calcium or magnesium and having densities of as high as 97% of theoretical or even higher is provided. Electrodes of such densities offer superior mechanical and electrical properties when employed in magneto-hydrodynamic generators.
Inventors
- 👤 Ronald Staut
- 👤 Peter E. D. Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:26
CPC Classifications
H; H02; H02K; H02K44/00; H02K44/08; H02K44/10; H01; H01B; H01B1/00; H01B1/06; H01B1/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
159 words
A method for producing an electrode body having the composition (La 1 -x Sr x ) CrO 3 , (La 1 -x Ca x ) CrO 3 , (La 1 -x Mg x ) CrO 3 , or La 1 Mg x Cr 1 -x O 3 , where x = 0 to 0.3, and a density in excess of 90% of theoretical, comprising the steps of: a. forming an aqueous solution of chromic acid, and reacting lanthanum oxide and strontium, calcium or magnesium carbonate or hydroxides or oxides in proportions to provide the aforesaid composition; drying said thick slurry to a dry cake; c. calcining said dry cake to a temperature of about 1000° to 1600°C.; d. grinding the calcined cake to a powder of particle size of less than about 100 mesh; e. forming said powder to an electrode-shape; and f. firing said electrode shape in an oxidizing atmosphere to a temperature of about 1500° to 2300°C.
Claim 2
Independent Claim
159 words
A method for producing an electrode body having the composition (La 1 -x Sr x ) CrO 3 , (La 1 -x Ca x ) CrO 3 , (La 1 -x Mg x ) CrO 3 , or La 1 Mg x Cr 1 -x O 3 , where x = 0 to 0.3, and a density in excess of 90% of theoretical, comprising the steps of: a. forming an aqueous solution of chromic acid, and reacting lanthanum oxide and strontium, calcium or magnesium carbonate or hydroxides or oxides in proportions to provide the aforesaid composition; drying said thick slurry to a dry cake; c. calcining said dry cake to a temperature of about 1000° to 1600°C.; d. grinding the calcined cake to a powder of particle size of less than about 100 mesh; e. forming said powder to an electrode-shape; and f. firing said electrode shape in an oxidizing atmosphere to a temperature of about 1500° to 2300°C.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said calcining is at a temperature of about 1200° to 1500°C.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said grinding is to a particle size of less than about 200 mesh.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein said firing is at a temperature of about 1700° to 2100°C.
References Cited (Backward Citations)
US3630968A
Cited
US3686519A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |