EP0261579A1
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EP
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A method for producing a rare earth metal-iron-boron permanent magnet by use of a rapidly-quenched alloy powder
Assignee: Tokin Corp
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Filing: 1987-09-16
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Granted: —
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Expires: 2007-09-16
Abstract
Abstract A rare earth metal-iron-boron permanent magnet is produced by the sintering method using a magnetic powder prepared from an ingot of R₂Fe₁₄B and another powder prepared from an rapidly-quenched alloy ribbon of R-T-B. R is at least one selected from yttrium and rare earth metals and T is at least one selected from transition metals. The rapidly-quenched alloy powder almost all melts to form a liquidus phase which cements the magnetic particles at a sintering temperature. The liquidus phase generates a magnetic crystalline phase and the solid solution phase upon cooling from the sintering temperature. A comparatively large amount of rapidly-quenched alloy powder is used to produce a magnet having a reduced amount of solid solution phase. In addition to this, the rapidly-quenched alloy can readily be finely ground and the rapidly-quenched alloy powder can therefore by uniformly mixed with the magnetic alloy powder so that the magnet having excellent magnetic properties can be produced wherein the magnetic particles are uniformly dispersed in the small amount of the solid solution phase. The magnet has a reduced oxygen content.
Inventors
- 👤 Tsutomu C/O Tokin Corporation Otsuka
- 👤 Etsuo C/O Tokin Corporation Otsuki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 18:16
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; B; B22; B22F; B22F1/00; B22F1/08; B22F1/09; B22F9/00; B22F9/002; B22F9/008; H01F1/0575; H01F1/0577
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
258 words
A method for producing an iron-rare earth metal-boron permanent magnetic body with a high energy product and a reduced oxygen content, said permanent magnet body comprising a solid solution phase and magnetic crystalline particles dispersed within said solid solution phase, which comprises steps of: preparing an ingot of R-T-B magnetic alloy comprising a magnetic intermetallic compound represented by a chemical formula of R₂T₁₄B, where R is at least one element selected from yttrium (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 alloy powder; preparing a rapidly quenched alloy body by rapidly quenching a melt comprising at least one metal element (R) selected from yttrium (Y) and rare earth metals and at least one of boron (B) and a transition metal (T); pulverizing and milling said rapidly quenched alloy body to thereby produce a rapidly-quenched alloy powder; mixing said rapidly-quenched alloy powder 70% or less by volume and said magnetic alloy powder of substantially balance to prepare a mixed powder; compacting said mixed powder into a compact body of a desired shape; and liquid sintering said compact body at an elevated liquid sintering temperature to produce the permanent magnetic body wherein said rapidly-quenched alloy powder melts to a liquidus phase which cements the magnetic alloy powder and a part of the liquidus phase substantially generates the magnetic crystalline particles and the remaining portion of the liquidus phase generates the solid solution phase upon cooling from the liquid sintering temperature.
Claim 2
Independent Claim
258 words
A method for producing an iron-rare earth metal-boron permanent magnetic body with a high energy product and a reduced oxygen content, said permanent magnet body comprising a solid solution phase and magnetic crystalline particles dispersed within said solid solution phase, which comprises steps of: preparing an ingot of R-T-B magnetic alloy comprising a magnetic intermetallic compound represented by a chemical formula of R₂T₁₄B, where R is at least one element selected from yttrium (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 alloy powder; preparing a rapidly quenched alloy body by rapidly quenching a melt comprising at least one metal element (R) selected from yttrium (Y) and rare earth metals and at least one of boron (B) and a transition metal (T); pulverizing and milling said rapidly quenched alloy body to thereby produce a rapidly-quenched alloy powder; mixing said rapidly-quenched alloy powder 70% or less by volume and said magnetic alloy powder of substantially balance to prepare a mixed powder; compacting said mixed powder into a compact body of a desired shape; and liquid sintering said compact body at an elevated liquid sintering temperature to produce the permanent magnetic body wherein said rapidly-quenched alloy powder melts to a liquidus phase which cements the magnetic alloy powder and a part of the liquidus phase substantially generates the magnetic crystalline particles and the remaining portion of the liquidus phase generates the solid solution phase upon cooling from the liquid sintering temperature.
Claim 3
Dependent Claim
15 words
A method as claimed in Claim 1, wherein said rapidly-quenched alloy comprises an amorphous alloy.
Claim 4
Dependent Claim
21 words
A method as claimed in Claim 1, wherein said rapidly quenched alloy has a microstructure that is a very fine crystalline.
Claim 5
Dependent Claim
60 words
A method as claimed in Claim 1, wherein said rapidly-quenched alloy comprises said at least one metal element (R) selected from Y and rare earth metals, said boron (B), and said transition metal (T), an amount of said at least one metal element (R) being determined more than the stoichiometric amount of metallic element (R) in the intermetallic compound R₂T₁₄B.
Claim 6
Dependent Claim
22 words
A method as claimed in Claim 4, wherein said at least one metal element is substantially 32 % or more by weight.
Claim 7
Dependent Claim
50 words
A method as claimed in Claim 1, wherein said rapidly-quenched alloy contains iron (Fe) alone as said transition metal (T) or Fe and at least one element selected from a group of Co, Ni, Cr, V, Ti, Mn, Cu, Zn, Zr, Nb, Mo, Hf, Ta, Al, Sn, Pb, and W.
Claim 8
Dependent Claim
28 words
A method as claimed in Claim 6, wherein an amount of at least one selected from Ni, Cr, V, Ti, and Mn is up to 0.7 molal ratio.
Claim 9
Dependent Claim
25 words
A method as claimed in Claim 6, wherein an amount of at least one selected from Cu and Zn is up to 0.6 molal ratio.
Claim 10
Dependent Claim
29 words
A method as claimed in Claim 6, wherein an amount of at least one selected from Zr, Nb, Mo, Hf, Ta, and W is up to 0.4 molal ratio.
Claim 11
Dependent Claim
34 words
A method as claimed in Claim 6, wherein said rapidly-quenched alloy contains Pb or Al or Cu or Cu and Ni or Cu, Co and Sn in addition to Fe as said transition metal.
Claim 12
Dependent Claim
31 words
A method as claimed in Claim 1, wherein said rapidly-quenched alloy contains Nd alone or Dy alone or Tb alone or Pr alone as said at least one metal element (R).
Claim 13
Dependent Claim
16 words
A method as claimed in Claim 1, wherein s aid R-T-B magnetic alloy contains Fe alone.
Claim 14
Dependent Claim
19 words
A method as claimed in Claim 1, wherein said liquid sintering is carried out at a temperature of 1,000-1,150°C.
Claim 15
Dependent Claim
46 words
An iron-rare earth metal-boron permanent magnetic body with a high coercive force, said magnetic body comprising a solid solution phase and magnetic crystalline particles uniformly dispersed in said solid solution phase, said magnetic body being characterized in that oxygen contained therein is 2,000 ppm or less
Claim 16
Dependent Claim
46 words
An iron-rare earth metal-boron permanent magnetic body with a high coercive force, said magnetic body comprising a solid solution phase and magnetic crystalline particles uniformly dispersed in said solid solution phase, said magnetic body being characterized in that oxygen contained therein is 2,000 ppm or less
Claim 17
Dependent Claim
88 words
A permanent magnet body as claimed in Claim 14, wherein said solid solution phase comprises at least one metal element (R) selected from yttrium and rare earth metals and at least one of boron (B) and a transition metal (T), and said each of said magnetic crystalline particles comprises a magnetic intermetallic compound represented by a chemical formula of R₂T₁₄B, where R is at least one element selected from yttrium (Y) and rare earth metals, T being transition metal but comprising Fe 50-100 wt.% in the transition metal.
Claim 18
Dependent Claim
39 words
A permanent magnet body as claimed in Claim 15, wherein said solid solution phase contains said at least one metal element (R) by an amount more than the stoichiometric amount of metallic element (R) in the intermetallic compound R₂T₁₄B.
Claim 19
Dependent Claim
23 words
A permanent magnet body as claimed in Claim 16, wherein said solid solution phase contains iron (Fe) alone as said transition metal (T).
Claim 20
Dependent Claim
45 words
A permanent magnet body as claimed in Claim 17, wherein said solid solution phase contains Fe and at least one substitution element selected from a group of Co, Ni, Cr, V, Ti, Mn, Cu, Zn, Zr, Nb, Mo, Hf, Ta, Al, Sn, Pb, and W.
Claim 21
Dependent Claim
31 words
A permanent magnet body as claimed in Claim 18, wherein an amount of said at least one selected from Ni, Cr, V, Ti, and Mn is up to 0.7 molal ratio.
Claim 22
Dependent Claim
28 words
A permanent magnet body as claimed in Claim 18, wherein an amount of said at least one selected from Cu and Zn is up to 0.6 molal ratio.
Claim 23
Dependent Claim
32 words
A permanent magnet body as claimed in Claim 18, wherein an amount of said at least one selected from Zr, Nb, Mo, Hf, Ta, and W is up to 0.4 molal ratio.
Claim 24
Dependent Claim
68 words
A permanent magnet body as claimed in Claim 18, wherein said solid solution phase contains Pb and/or Al and/or Cu or Cu and Ni or Cu, Co, and Sn in addition to Fe as said transition metal, said Pb and/or Al and/or Cu or Cu and Ni or Cu, Co, and Sn being concentrated in the vicinity of an outer surface of each of said magnetic crystalline particles.
References Cited (Backward Citations)
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