US3846322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing large single crystals of mixed ferrites
Assignee: Individual
•
Filing: 1970-06-11
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Granted: 1974-11-05
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Expires: 1990-06-11
Abstract
Abstract The present invention relates to a method for producing a large single crystal of a mixed ferrite containing ZnO and having a spinel structure by melting the raw materials under an oxygen atmosphere with a pressure of from 1.5 to 20 atmospheres at a temperature of from 1,600* to 1,800*C to reduce the amount of ferrous ion contained in the molten ferrite to less than 7 wt. percent, and cooling the molten ferrite at the rate of from 2* to 8*C/hour to carry out the crystal growth by the Bridgman technique.
Inventors
- 👤 H Watanabe
- 👤 M Sugimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:41
CPC Classifications
C; C30; C30B; C30B11/00; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/265; C04B35/2658; C30B13/00; C30B29/00; C30B29/10; C30B29/16; C30B29/22; C30B29/26
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
183 words
A METHOD FOR PRODUCING A LARGE SINGLE CRYSTAL OF A MIXED FERRITE WHICH IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF MANGANESE-ZINC FERRITE AND NICKEL-ZINC FERRITE WITH A SPINEL OF STRUCTURE, CONTAINING ZINC OXIDE IN THE AMOUNT OF BETWEEN 2 AND 30 MOLE PER CENT, WHICH COMPRISES MELTING RAW MATERIALS FOR THE FERRITE IN A HEATING ZONE AT A TEMPERATURE ABOVE 1,600* TO 1,800*C IN AN ATOMPHERE CONSISTING ESSENTIALLY OF OXYGEN HAVING A PARTIAL PRESSURE OF OXYGEN OF FROM 1.5 TO 20 ATOMOSPHERES TO REDUCE THE CONTENT OF FERROUS ION IN THE MOLTEN FERRITE TO LESS THAN 7WT. PER CENT OF THE TOTAL AMOUNT OF IRON AND SUBSEQUENTLY COOLING THE MOLTEN FERRITE AT THE RATE OF 2* -8*/HOUR BY SLOWLY MOVING SAID MOLTEN FERRITE RELATIVE TO AND OUT OF SAID HEATING ZONE IN AN ATOMPHERE CONSISTING ESSENTIALLY OF OXYGEN HAVING A PARTIAL PRESSURE OF OXYGEN OF FROM 1.5 TO 20 ATMOSPHERES TO CARRRY OUT THE CRYSTAL GROWTH, WHEREBY A SINGLE CRYSTAL HAVING THE DIMENSION OF AT LEAST ABOUT 20 MM IN DIAMETER AND AT LEAST ABOUT 30 MM IN LENGTH IS PRODUCED.
Claim 2
Independent Claim
183 words
A METHOD FOR PRODUCING A LARGE SINGLE CRYSTAL OF A MIXED FERRITE WHICH IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF MANGANESE-ZINC FERRITE AND NICKEL-ZINC FERRITE WITH A SPINEL OF STRUCTURE, CONTAINING ZINC OXIDE IN THE AMOUNT OF BETWEEN 2 AND 30 MOLE PER CENT, WHICH COMPRISES MELTING RAW MATERIALS FOR THE FERRITE IN A HEATING ZONE AT A TEMPERATURE ABOVE 1,600* TO 1,800*C IN AN ATOMPHERE CONSISTING ESSENTIALLY OF OXYGEN HAVING A PARTIAL PRESSURE OF OXYGEN OF FROM 1.5 TO 20 ATOMOSPHERES TO REDUCE THE CONTENT OF FERROUS ION IN THE MOLTEN FERRITE TO LESS THAN 7WT. PER CENT OF THE TOTAL AMOUNT OF IRON AND SUBSEQUENTLY COOLING THE MOLTEN FERRITE AT THE RATE OF 2* -8*/HOUR BY SLOWLY MOVING SAID MOLTEN FERRITE RELATIVE TO AND OUT OF SAID HEATING ZONE IN AN ATOMPHERE CONSISTING ESSENTIALLY OF OXYGEN HAVING A PARTIAL PRESSURE OF OXYGEN OF FROM 1.5 TO 20 ATMOSPHERES TO CARRRY OUT THE CRYSTAL GROWTH, WHEREBY A SINGLE CRYSTAL HAVING THE DIMENSION OF AT LEAST ABOUT 20 MM IN DIAMETER AND AT LEAST ABOUT 30 MM IN LENGTH IS PRODUCED.
Claim 3
Dependent Claim
62 words
A method according to claim 1, wherein the single crystal with the spinel structure and containing ferrous ion in amount of less than 7 wt. percent of the total amount of iron thus produced is reheated at a temperature below 1,300*C in an oxidizing atmosphere to reduce and control the amount of ferrous ion without causing any modification of the crystal structure.
Claim 4
Dependent Claim
31 words
A method according to claim 1, wherein the oxygen atmosphere employed during melting and during the process of the crystal growth is at a pressure of from 3 to 10 atmospheres.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |