Patent JPS551491A successfully refreshed from Google Patents.
EP0249973A1
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Permanent magnetic material and method for producing the same
Assignee: Tokin Corp
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Filing: 1987-06-16
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Granted: —
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Expires: 2007-06-16
Abstract
Abstract A permanent magnetic material of a desired bulk shape is obtained which comprises a composite microstructure consisting of magnetic particles of Nd 2 Fe 14 B dispersed within a metallic cementing phase of 10% or less by volume of the magnetic material. A magnetic powder is prepared from an alloy comprising Nd 2 Fe 14 B compound and is mixed with an alloy powder having a melting point lower than the peritectic temperature of Nd 2 Fe, 4 B, and the mixed powder is sintered at a temperature higher than the melting point but lower than the peritectic temperature, so that the alloy powder melts and forms the cementing phase covering each magnetic particle to thereby realize high coercive force and excellent corrosion resistance. In place of Nd, other rare earth metal or metals can be used. A part of Fe can be replaced by other transition metal or metals. For the cementing metallic element or elements, Al, Zn, Sn, Cu, Pb, S, In Ga, Ge, and Te can be used.
Inventors
- 👤 Kinya Sasaki
- 👤 Etsuo Otsuki
- 👤 Tsutomu Otsuka
- 👤 Teruhiko Fujiwara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 19:11
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H01F1/0571; H01F1/0575; H01F1/0578; B; B22; B22F; B22F1/00; B22F1/09; H01F1/0577
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
134 words
A magnetic body with a high coercive force for a permanent magnet which consists essentially of a metallic cementing phase and magnetic crystalline particles uniformly dispersed within said metal cementing phase, said cementing phase being 10% or less by volume of said magnetic body and comprising at least one element selected from a first metallic group of Al, Zn, Sn, Cu, Pb, S, In, Ga, Ge, and Te, said magnetic crystalline particles being substantially balance of the volume of the magnetic body and being a composition represented by a chemical formula R2T14B, where R is at least one element selected from Y and rare earth metals, T being transition metals and comprising Fe 50-100 at% in the transition metal, each of said magnetic particles being embedded in said'cementing phase to form an interface therebetween.
Claim 2
Dependent Claim
134 words
A magnetic body with a high coercive force for a permanent magnet which consists essentially of a metallic cementing phase and magnetic crystalline particles uniformly dispersed within said metal cementing phase, said cementing phase being 10% or less by volume of said magnetic body and comprising at least one element selected from a first metallic group of Al, Zn, Sn, Cu, Pb, S, In, Ga, Ge, and Te, said magnetic crystalline particles being substantially balance of the volume of the magnetic body and being a composition represented by a chemical formula R2T14B, where R is at least one element selected from Y and rare earth metals, T being transition metals and comprising Fe 50-100 at% in the transition metal, each of said magnetic particles being embedded in said'cementing phase to form an interface therebetween.
Claim 3
Dependent Claim
39 words
A magnetic body as claimed in Claim 1, said cementing phase comprising an intermetallic compound of at least one of said first metallic group and at least one selected from a second metallic group of R, T, and B.
Claim 4
Dependent Claim
147 words
A method for producing a magnetic body with a high coercive force for a permanent magnet comprising steps of: preparing an ingot of R-T-B magnetic alloy comprising a magnetic intermetallic compound (Claim 3 continued) represented by a chemical formula of R 2 T 14 B, where R is at least one element selected from Y and rare earth metals, T being transition metal but comprising Fe 50-100 at% in the transition metal; pulverizing and milling said ingot to thereby prepare a magnetic powder; preparing a metallic cementing powder comprising at least one element selected from a first metallic group of Al, Zn, Sn, Cu, Pb, S, In, Ga, Ge, and Te; mixing a metallic cementing powder of 10% or less by volume and said magnetic powder of substantially balance to prepare a mixed powder; and forming a bulk-shape body of said mixed powder at an elevated temperature.
Claim 5
Dependent Claim
72 words
A method as claimed in Claim 3, said bulk-shape body forming step comprising; compacting said mixed powder under influence of a grain aligning magnetic field into a compact body of a predetermined shape; and sintering said compact body at a temperature lower than a peritectic reaction temperature of said magnetic powder but higher than a melting temperature of said metallic cementing powder to thereby produce, as said bulk-shape body, a sintered body.
Claim 6
Dependent Claim
61 words
A method as claimed in Claim 4, wherein said R-T-B ingot consists of said intermetallic compound of R 2 T 14 B, and said metallic cementing powder comprises an (Claim 5 continued) intermetallic compound of at least one element selected 5 from said first metallic group and at least one selected from a second metallic group of R, T, and B.
Claim 7
Dependent Claim
29 words
A method as claimed in Claim 5, further comprising a step of subjecting said sintered body to a heat treatment for improving the magnetic properties of the sintered body.
Claim 8
Dependent Claim
16 words
A method as claimed in Claim 6, wherein said heat treatment is performed at 300-900 °C.
Claim 9
Dependent Claim
46 words
A method as claimed in Claim 3, wherein said bulk-shape body forming step is a hot compaction process for hot compacting said mixed powder into said bulk-shape body at an elevated temperature lower than 1,100°C but higher than a melting temperature of said metallic cementing powder.
Claim 10
Dependent Claim
34 words
A method as claimed in Claim 8, wherein said hot compaction process is a hot pressing process for hot pressing said mixed powder into said bulk-shape body under a pressure of 5-5,000 Kg.f/cm .
Claim 11
Dependent Claim
38 words
A method as claimed in Claim 9, said bulk shape body forming step further comprising a step of previously compacting said mixed powder to form a green compact, said green compact being then subjected to said hot-pressing process.
Claim 12
Dependent Claim
18 words
A method as claimed in Claim 10, wherein said compacting step is performed within an aligning magnetic field.
Claim 13
Dependent Claim
51 words
A method as claimed in Claim 8, wherein said hot compaction process comprises steps of compacting said mixed powder to form a green compact, heating said green compact at said elevated temperature, and then subjecting said heated green compact to extrusion to thereby produce, as said bulk-shape body, an extruded body.
Claim 14
Dependent Claim
22 words
A method as claimed in Claim 12, wherein said green compact is coated with a heat insulating material prior to said extrusion.
Claim 15
Dependent Claim
26 words
A method as claimed in Claim 8, further comprising a step of subjecting said bulk-shape body to a heat treatment for improving the magnetic properties thereof.
Claim 16
Dependent Claim
16 words
A method as claimed in Claim 14, wherein said heat treatment is performed at 300-900 °C.
References Cited (Backward Citations)
EP0166597A2
Cited
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