US4381216A
Expired / Lapsed
US
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Method of etching to form cationically-conductive ceramic body
Assignee: General Electric Co
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Filing: 1981-08-03
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Granted: 1983-04-26
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Expires: 2001-08-03
Abstract
Abstract A cationically-conductive polycrystalline body having a specific resistivity at its surface portion higher than its specific intrinsic resistivity is contacted with phosphoric acid to produce an etched body having a uniform specific intrinsic resistivity.
Inventors
- 👤 Raj N. Singh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:43
CPC Classifications
H; H01; H01M; H01M10/00; H01M10/36; H01M10/39; H01M10/3909; H01M10/3918; C; C04; C04B; C04B41/00; C04B41/53; C04B41/5338; C04B41/5353; C09; C09K; C09K13/00; C09K13/04; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
170 words
A process for producing a cationically-conductive ceramic body having an etched surface and a specific resistivity at its surface portion which is at least not significantly different from its specific intrinsic resistivity which comprises providing a cationically-conductive ceramic body having a specific resistivity at its surface portion significantly higher than its specific intrinsic resistivity, said ceramic body ranging in composition from an alkali metal beta-alumina phase to an alkali metal beta"-alumina phase including all combinations of said alkali metal beta-alumina phase and said alkali metal beta"-alumina phase, said alkali metal being selected from the group consisting of sodium, potassium, lithium, mixtures thereof and alloys thereof, and etching the surface portion of said ceramic body with phosphoric acid to produce said cationically-conductive ceramic body with a specific resistivity at its surface portion which is at least not significantly different from its specific intrinsic resistivity, said phosphoric acid having a concentration of P 2 O 5 which etches said ceramic body, said etching having no significant deleterious effect on said ceramic body.
Claim 2
Dependent Claim
170 words
A process for producing a cationically-conductive ceramic body having an etched surface and a specific resistivity at its surface portion which is at least not significantly different from its specific intrinsic resistivity which comprises providing a cationically-conductive ceramic body having a specific resistivity at its surface portion significantly higher than its specific intrinsic resistivity, said ceramic body ranging in composition from an alkali metal beta-alumina phase to an alkali metal beta"-alumina phase including all combinations of said alkali metal beta-alumina phase and said alkali metal beta"-alumina phase, said alkali metal being selected from the group consisting of sodium, potassium, lithium, mixtures thereof and alloys thereof, and etching the surface portion of said ceramic body with phosphoric acid to produce said cationically-conductive ceramic body with a specific resistivity at its surface portion which is at least not significantly different from its specific intrinsic resistivity, said phosphoric acid having a concentration of P 2 O 5 which etches said ceramic body, said etching having no significant deleterious effect on said ceramic body.
Claim 3
Dependent Claim
12 words
The process according to claim 1 wherein said alkali metal is sodium.
Claim 4
Dependent Claim
26 words
The process according to claim 1 wherein said etching is carried out at a temperature ranging from about room temperature to a temperature below 250° C.
Claim 5
Dependent Claim
51 words
The process according to claim 1 wherein said ceramic body is also polished by said phosphoric acid producing a cationically-conductive ceramic body having an etched surface portion and a polished surface portion with the specific resistivity at its surface portions being at least not significantly different from its specific intrinsic resistivity.
Claim 6
Dependent Claim
16 words
The process according to claim 1 wherein said ceramic body is immersed in said phosphoric acid.
Claim 7
Dependent Claim
25 words
The process according to claim 1 wherein said ceramic body contains alkali metal beta"-alumina phase and contains a stabilizer for said alkali metal beta"-alumina phase.
Claim 8
Dependent Claim
25 words
The process according to claim 6 wherein said stabilizer is selected from the group consisting of Li 2 O, MgO, NiO, CoO and mixtures thereof.
Claim 9
Dependent Claim
31 words
The process according to claim 1 wherein said ceramic body is in the form of a hollow tube closed at one end and useful as an electrolyte in a sodium-sulfur cell.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-04-25 | 1986-10-25 | 1987-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-25 | 1990-10-25 | 1991-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-25 | 1994-10-25 | 1995-04-26 | $7700.00 | Window Closed / Lapsed |