US3983916A
Expired / Lapsed
US
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Process for producing semi-hard co-nb-fl magnetic materials
Assignee: Fujitsu Ltd
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Filing: 1974-11-04
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Granted: 1976-10-05
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Expires: 1994-11-04
Abstract
Abstract A semi-hard magnetic material characterized by a high coercive force (Hc), i.e. 20-50 Oe, can be produced by the disclosed process. In accordance with the process, an alloy consisting of 73 to 93% Co and 3 to 7% Nb, and the balance being iron is worked into a suitable form, solution treated, cold worked at a reduction of area not lower than 75% and aged. Said alloy contains niobium in a greater amount than the known alloy for the same application in order to enhance the coercive force. With the increase in the content of niobium, however, the cold workability of the alloy deteriorates. In order to overcome this disadvantage, the Inventors provide particular conditions for the solution treatment. The solution treatment consists of heating the alloy to a temperature not lower than 1000°C and cooling it to room temperature. During the cooling, quenching of the alloy should be started at 800°C or higher and continued to a temperature of 500°C or less.
Inventors
- 👤 Zenzo Henmi
- 👤 Masanori Okada
- 👤 Makoto Kassai
- 👤 Takehiko Sato
- 👤 Toshio Kobayashi
- 👤 Etsuo Hanada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:06
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; C; C22; C22C; C22C19/00; C22C19/07
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
142 words
A process for producing a semi-hard magnetic material having a coercive force of from 20 to 50 Oe, said process comprising the steps of: working an ingot of alloy consisting essentially, by weight, of 73 to 93% of cobalt, 3 to 7% of niobium, and 6 to 18% iron, into an article having a suitable form; subjecting the article to solution treatment by heating the article to a solution temperature not lower than 1000°C; cooling said article from said solution temperature to room temperature wherein said step of cooling includes quenching said article from at least 800° to 500°C; subjecting the quenched article to cold working at a reduction of area not less than 75%; and ageing the cold worked article at a temperature from 500° to 900°C selected to yield a squareness ratio above 0.8 and a fullness factor over 0.7.
Claim 2
Dependent Claim
142 words
A process for producing a semi-hard magnetic material having a coercive force of from 20 to 50 Oe, said process comprising the steps of: working an ingot of alloy consisting essentially, by weight, of 73 to 93% of cobalt, 3 to 7% of niobium, and 6 to 18% iron, into an article having a suitable form; subjecting the article to solution treatment by heating the article to a solution temperature not lower than 1000°C; cooling said article from said solution temperature to room temperature wherein said step of cooling includes quenching said article from at least 800° to 500°C; subjecting the quenched article to cold working at a reduction of area not less than 75%; and ageing the cold worked article at a temperature from 500° to 900°C selected to yield a squareness ratio above 0.8 and a fullness factor over 0.7.
Claim 3
Dependent Claim
30 words
A process according to claim 1, wherein the alloy consist essentially, by weight, of 78 to 90% of cobalt, 3 to 7% of niobium and 6 to 18% of iron.
Claim 4
Dependent Claim
30 words
A process according to claim 1, wherein the alloy consist essentially, by weight, of 80 to 87% of cobalt, 4 to 5% of niobium and 9 to 15% of iron.
Claim 5
Dependent Claim
12 words
A process according to claim 1, wherein said solution temperature is 1100°C.
Claim 6
Dependent Claim
12 words
A process according to claim 2, wherein said solution temperature is 1100°C.
Claim 7
Dependent Claim
159 words
A process for producing a semi-hard magnetic material having a coercive force of from 20 to 50 Oe, said process comprising the steps of: working an ingot of alloy consisting essentially by weight, of 73 to 93% of cobalt, 3 to 7% of niobium, and 6 to 18% iron, into an article having a suitable form; heating the article to a solution temperature not lower than 1000°C; cooling said article from said solution temperature to a first temperature of not lower than 800°C; quenching said article from said first temperature to a second temperature of 500°C at the highest, said second temperature being substantially higher than room temperature; cooling said article to room temperature; subjecting said room temperature cooled article to cold working at a reduction of area not less than 75%; and ageing the cold worked article at a temperature from 500° to 900°C selected to yield a squareness ratio above 0.8 and a fullness factor over 0.7.
Claim 8
Dependent Claim
159 words
A process for producing a semi-hard magnetic material having a coercive force of from 20 to 50 Oe, said process comprising the steps of: working an ingot of alloy consisting essentially by weight, of 73 to 93% of cobalt, 3 to 7% of niobium, and 6 to 18% iron, into an article having a suitable form; heating the article to a solution temperature not lower than 1000°C; cooling said article from said solution temperature to a first temperature of not lower than 800°C; quenching said article from said first temperature to a second temperature of 500°C at the highest, said second temperature being substantially higher than room temperature; cooling said article to room temperature; subjecting said room temperature cooled article to cold working at a reduction of area not less than 75%; and ageing the cold worked article at a temperature from 500° to 900°C selected to yield a squareness ratio above 0.8 and a fullness factor over 0.7.
Claim 9
Dependent Claim
30 words
A process according to claim 6, wherein the alloy consists essentially, by weight, of 78 to 90% of cobalt, 3 to 7% of niobium and 6 to 18% of iron.
Claim 10
Dependent Claim
30 words
A process according to claim 6, wherein the alloy consists essentially, by weight of 80 to 87% of cobalt, 4 to 5% of niobium and 9 to 15% of iron.
Claim 11
Dependent Claim
150 words
A process for producing a semi-hard magnetic material having a coercive force of from 20 to 50 Oe, said process comprising the steps of: working an ingot of alloy consisting essentially by weight, of 73 to 93% of cobalt, 3 to 7% of niobium, and 6 to 18% iron, into an article having a suitable form; heating the article to a solution temperature not lower than 1000°C; quenching said article from said solution temperature to a first temperature in the range of 300° to 500°C; maintaining said article at said first temperature for a predetermined time; cooling said article from said first temperature to room temperature; subjecting the cooled article to cold working at a reduction of area not less than 75%; and ageing the cold worked article at a temperature from 500° to 900°C selected to yield a squareness ratio above 0.8 and and a fullness factor over 0.7.
Claim 12
Dependent Claim
150 words
A process for producing a semi-hard magnetic material having a coercive force of from 20 to 50 Oe, said process comprising the steps of: working an ingot of alloy consisting essentially by weight, of 73 to 93% of cobalt, 3 to 7% of niobium, and 6 to 18% iron, into an article having a suitable form; heating the article to a solution temperature not lower than 1000°C; quenching said article from said solution temperature to a first temperature in the range of 300° to 500°C; maintaining said article at said first temperature for a predetermined time; cooling said article from said first temperature to room temperature; subjecting the cooled article to cold working at a reduction of area not less than 75%; and ageing the cold worked article at a temperature from 500° to 900°C selected to yield a squareness ratio above 0.8 and and a fullness factor over 0.7.
Claim 13
Dependent Claim
18 words
A process according to claim 9, wherein said solution temperature is 1100°C and said first temperature is 500°C.
Claim 14
Dependent Claim
31 words
A process according to claim 9, wherein said alloy consists essentially of, by weight, of 78 to 90% of cobalt, 3 to 7% of niobium and 6 to 18% of iron.
Claim 15
Dependent Claim
18 words
A process according to claim 11, wherein said solution temperature is 1100°C and said first temperature is 500°C.
Claim 16
Dependent Claim
18 words
A process according to claim 1, wherein said article is quenched from the solution temperature to room temperature.
Claim 17
Dependent Claim
18 words
A process according to claim 2, wherein said article is quenched from the solution temperature to room temperature.
References Cited (Backward Citations)
US3065118A
Cited
US3189493A
Cited
US3390443A
Cited
US3743550A
Cited
US3801312A
Cited
US3698055A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-05 | 1980-04-05 | 1980-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-05 | 1984-04-05 | 1984-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-05 | 1988-04-05 | 1988-10-05 | $7700.00 | Window Closed / Lapsed |