US3767580A
Expired / Lapsed
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Process for treating ferromagnetic chromium dioxide
Assignee: Fujifilm Holdings Corp
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Filing: 1971-10-20
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Granted: 1973-10-23
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Expires: 1991-10-20
Abstract
Abstract In the production of ferromagnetic chromium dioxide or modified chromium dioxide containing guest-components, such as Te or Sb, chromium ions from water-soluble chromium compounds remaining in the final product cause various disadvantages. These disadvantages have now been overcome by treating the final product consisting mainly of ferromagnetic chromium dioxide or modified chromium dioxide with a compound, such as barium chloride or sodium hydroxide, which reacts with the chromium ions to form water-insoluble chromium compounds.
Inventors
- 👤 T Kitamoto
- 👤 G Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70636; C; C01; C01G; C01G37/00; C01G37/02; C01P; C01P2006/00; C01P2006/42; C01P2006/80
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
35 words
A process according to claim 1 wherein said thermal de-composition or oxidation is conducted in the presence of guest components which become part of the ferromagnetic chromium dioxide and which improve the ferromagnetic properties thereof.
Claim 2
Dependent Claim
58 words
A process according to claim 2 wherein said guest components are selected from the group consisting of ruthenium, antimony, tin, sodium, potassium, vanadium, manganese, iron, cobalt, nickel, fluorine and tellurium and wherein said guest components are present in said product ferromagnetic chromium dioxide in an amount of not greater than 10 atomic percent, based on said chromium dioxide.
Claim 3
Dependent Claim
31 words
A process according to claim 3 wherein said unreacted water-soluble chromium ions are derived from anhydrous chromic acid, salts thereof, salts of bichromic acid, trivalent chromium chloride or trivalent chromium nitrate.
Claim 4
Dependent Claim
16 words
A process according to claim 1, wherein said compound used in said treatment is silver nitrate.
Claim 5
Dependent Claim
30 words
A process according to claim 1, wherein said compound used in said treatment is a zinc compound selected from the group consisting of zinc chloride, zinc nitrate and zinc acetate.
Claim 6
Dependent Claim
28 words
A process according to claim 1, wherein said compound used in said treatment is a barium compound selected from the group consisting of barium chloride and barium nitrate.
Claim 7
Dependent Claim
30 words
A process according to claim 1, wherein said compound used in said treatment is a lead compound selected from the group consisting of lead chloride, lead nitrate and lead acetate.
Claim 8
Dependent Claim
28 words
A process according to claim 1, wherein said compound used in said treatment is an alkali compound selected from the group consisting of sodium hydroxide and potassium hydroxide.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |