US3555265A
Expired / Lapsed
US
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Fine particle magnetic material
Assignee: Hitachi Metals International Ltd
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Filing: 1967-12-18
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Granted: 1971-01-12
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Expires: 1987-12-18
Abstract
Abstract Fine particle magnetic material prepared by electrodeposition of iron or iron-cobalt alloys into a mercury cathode is coated with a protective coating of antimony and then placed in a lead matrix containing a small but critical percentage of an additive material which may be calcium, tin or a tin-base alloy. The additive material acts to enhance the dimensional stability and retard the growth of whiskers on the resulting magnet.
Inventors
- 👤 John R Feller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:39
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/0551; H01F1/0552; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12181; Y10T428/12465; Y10T428/12493; Y10T428/12681
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
Fine particle magnetic material consisting essentially of single magnetic domain particles selected from the group consisting of iron and alloys of iron and cobalt, each of said particles containing an antimony protective coating and a lead matrix and from a trace quantity of about 0.001 up to 0.04 part by weight per part by weight of lead of an additive selected from the group consisting of calcium, tin, and tin-base alloys, said additive being homogeneously and uniformly distributed throughout said matrix in a quantity sufficient to enhance dimensional stability and reduce whisker growth of the magnetic material.
Claim 2
Dependent Claim
97 words
Fine particle magnetic material consisting essentially of single magnetic domain particles selected from the group consisting of iron and alloys of iron and cobalt, each of said particles containing an antimony protective coating and a lead matrix and from a trace quantity of about 0.001 up to 0.04 part by weight per part by weight of lead of an additive selected from the group consisting of calcium, tin, and tin-base alloys, said additive being homogeneously and uniformly distributed throughout said matrix in a quantity sufficient to enhance dimensional stability and reduce whisker growth of the magnetic material.
Claim 3
Dependent Claim
22 words
The fine particle magnetic material of claim 1 in which the additive is from 0.001 to 0.02 part by weight of tin.
Claim 4
Dependent Claim
16 words
The fine particle magnetic material of claim 1 in which the additive is a tin-base alloy.
Claim 5
Dependent Claim
53 words
Fine particle magnetic material consisting essentially of elongated single magnetic domain particles selected from the group consisting of iron and alloys of iron and cobalt, each of said particles containing an antimony coating and a lead matrix and from 0.00l to 0.02 part by weight of tin per part by weight of lead.
Claim 6
Dependent Claim
53 words
Fine particle magnetic material consisting essentially of elongated single magnetic domain particles selected from the group consisting of iron and alloys of iron and cobalt, each of said particles containing an antimony coating and a lead matrix and from 0.00l to 0.02 part by weight of tin per part by weight of lead.
Claim 7
Dependent Claim
138 words
A process for producing fine particle magnetic material comprising electrolytically depositing fine magnetic particles selected from the group consisting of iron and alloys of iron and cobalt into a liquid metal cathode of mercury, coating said magnetic particles with an antimony protective coating material and placing said coated particles in a lead matrix, then adding to said matrix from a trace amount of about 0.001 up to 0.04 part by weight per part by weight of the lead matrix of an additive selected from the group consisting of calcium, tin, and tin-base alloys, said additive being homogeneously and uniformly distributed throughout said matrix in a quantity sufficient to enhance dimensional stability and reduce whisker growth of the magnetic material, separating the cathode from said coated fine particle-matrix mixture and forming said particles and matrix into a magnet structure.
Claim 8
Dependent Claim
138 words
A process for producing fine particle magnetic material comprising electrolytically depositing fine magnetic particles selected from the group consisting of iron and alloys of iron and cobalt into a liquid metal cathode of mercury, coating said magnetic particles with an antimony protective coating material and placing said coated particles in a lead matrix, then adding to said matrix from a trace amount of about 0.001 up to 0.04 part by weight per part by weight of the lead matrix of an additive selected from the group consisting of calcium, tin, and tin-base alloys, said additive being homogeneously and uniformly distributed throughout said matrix in a quantity sufficient to enhance dimensional stability and reduce whisker growth of the magnetic material, separating the cathode from said coated fine particle-matrix mixture and forming said particles and matrix into a magnet structure.
Claim 9
Dependent Claim
19 words
The process of claim 5 in which the additive is from 0.001 to 0.02 part by weight of tin.
Claim 10
Dependent Claim
122 words
A process for producing fine particle magnetic material comprising electrolytically depositing fine magnetic particles selected from the group consisting of iron and alloys of iron and cobalt into a mercury cathode, coating said magnetic particles with a protective antimony coating and placing said particles in a lead matrix, then adding to said matrix from 0.001 to 0.02 part by weight of tin per part by weight of the lead matrix, heat-treating for a brief period of time said mixture of mercury cathode, fine particles and matrix at 150-200* C. to homogenize and uniformly distribute the additive in the matrix, removing by vacuum distillation the mercury cathode from the coated fine particle-matrix mixture, and forming said particles and matrix into a magnet structure.
Claim 11
Dependent Claim
122 words
A process for producing fine particle magnetic material comprising electrolytically depositing fine magnetic particles selected from the group consisting of iron and alloys of iron and cobalt into a mercury cathode, coating said magnetic particles with a protective antimony coating and placing said particles in a lead matrix, then adding to said matrix from 0.001 to 0.02 part by weight of tin per part by weight of the lead matrix, heat-treating for a brief period of time said mixture of mercury cathode, fine particles and matrix at 150-200* C. to homogenize and uniformly distribute the additive in the matrix, removing by vacuum distillation the mercury cathode from the coated fine particle-matrix mixture, and forming said particles and matrix into a magnet structure.
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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |