EP0411571A2
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EP
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Rare earth permanent magnet powder, method for producing same and bonded magnet
Assignee: Mitsubishi Materials Corp
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Filing: 1990-07-31
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Granted: —
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Expires: 2010-07-31
Abstract
Abstract There is disclosed a R-Fe-B or R-Fe-Co-B alloy permanent magnet powder which may contain Ga, Zr or Hf, or may further contain Al, Si or V. R stands for a rare earth element including yttrium. Each individual particle of the powder includes a structure of recrystallized grains containing a R 2 Fe 14 B or R 2 (Fe,Co) 14 B intermetallic compound phase. The intermetallic compound phase has recrystallized grains of a tetragonal crystal structure having an average crystal grain size of 0.05 to 20µm. At least 50% by volume of the recrystallized grains of the aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain. In order to manufacture the magnet powder, regenerative material and alloy material are prepared and their temperature is elevated in a hydrogen atmosphere. Then, the alloy material and the regenerative material are held in the same atmosphere at a temperature of 750°C to 950°C, and then held in a vacuum at 750°C to 950°C, and cooled and crushed. A bonded magnet produced using the above magnet powder is also disclosed.
Inventors
- 👤 Ryoji C/O Chuo-Kenkyusho Nakayama
- 👤 Takuo C/O Chuo-Kenkyusho Takeshita
- 👤 Tamotsu C/O Chuo-Kenkyusho Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:13
CPC Classifications
B; B22; B22F; B22F9/00; B22F9/02; B22F9/023; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H01F1/0571; H01F1/0573
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
162 words
A rare earth permanent magnet powder which exhibits superior magnetic anisotropy and high resistance to corrosion, characterized in that each particle contains 10 to 20 atomic percent of R (wherein A is an rare earth element including yttrium (Y)) 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R 2 Fe, 4 .B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20µrn, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain.
Claim 2
Dependent Claim
162 words
A rare earth permanent magnet powder which exhibits superior magnetic anisotropy and high resistance to corrosion, characterized in that each particle contains 10 to 20 atomic percent of R (wherein A is an rare earth element including yttrium (Y)) 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R 2 Fe, 4 .B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20µrn, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain.
Claim 3
Dependent Claim
153 words
A rare earth permanent magnet powder which exhibits superior magnetic anisotropy and high resistance to corrosion, comprising particles each containing 10 to 20 atomic percent of R, 0.1 to 50 atomic percent of Co, 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R2(Fe,Co)14B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20µm, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain.
Claim 4
Dependent Claim
153 words
A rare earth permanent magnet powder which exhibits superior magnetic anisotropy and high resistance to corrosion, comprising particles each containing 10 to 20 atomic percent of R, 0.1 to 50 atomic percent of Co, 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R2(Fe,Co)14B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20µm, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain.
Claim 5
Dependent Claim
41 words
A rare earth permanent magnet powder according to claim 1 or claim 2, wherein a part of Fe is substituted by 0.01 to 2.0 atomic percent of at least one element selected from the group consisting of Al, V and Si.
Claim 6
Dependent Claim
30 words
A rare earth permanent magnet powder according to claim 1, claim 2 or claim 3, wherein the average crystal grain size of the recrystallized grains ranges from 0.05 to 3nm.
Claim 7
Dependent Claim
26 words
A rare earth permanent magnet powder according to claim 4, in which said aggregated structure essentially consists of the recrystallized grains of said intermetallic compound phases.
Claim 8
Independent Claim
83 words
A method for producing a rare earth permanent magnet powder chracterized by the steps of: (a) preparing a rare earth alloy material and a regenerative material; (b) subsequently elevating the temperature of said alloy material and said regenerative material in a hydrogen atmosphere and holding the same in said atmosphere at a temperature of 750°C/to 950°C; (c) subsequently holding said alloy and said regenerative material at a temperature of 750°C to 950°C in a vacuum; and (d) subsequently cooling and crushing said alloy.
Claim 9
Independent Claim
83 words
A method for producing a rare earth permanent magnet powder chracterized by the steps of: (a) preparing a rare earth alloy material and a regenerative material; (b) subsequently elevating the temperature of said alloy material and said regenerative material in a hydrogen atmosphere and holding the same in said atmosphere at a temperature of 750°C/to 950°C; (c) subsequently holding said alloy and said regenerative material at a temperature of 750°C to 950°C in a vacuum; and (d) subsequently cooling and crushing said alloy.
Claim 10
Dependent Claim
28 words
A method for producing a rare earth permanent magnet powder according to claim 6, further comprising subjecting said alloy material to homogenization prior to said holding step (b).
Claim 11
Dependent Claim
27 words
A method for producing a rare earth permanent magnet powder according to claim 7, wherein said homogenization is carried out at a temperature of 600°C to 1200°C.
Claim 12
Dependent Claim
29 words
A method for producing a rare earth permanent magnet powder according to claim 6, further comprising subjecting the crushed powder to heat-treatment at a temperature of 300°C to 1000°C.
Claim 13
Dependent Claim
50 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 14
Dependent Claim
57 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 40 atomic percent of Co, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 15
Dependent Claim
57 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 5.0 atomic percent of Ga, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 16
Dependent Claim
79 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 5.0 atomic percent of Ga, 0.01 to 3.0 atomic percent of at least one element selected from the group consisting of Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element inclusive of yttrium.
Claim 17
Dependent Claim
69 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 3.0 atomic percent of at least one element selected from the group consisting of Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 18
Dependent Claim
64 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 5.0 atomic percent of Ga, 0.01 to 40 atomic percent of Co, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 19
Dependent Claim
83 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 5.0 atomic percent of Ga, 0.01 to 3.0 atomic percent of at least one element selected from the group consisting of Zr and Hf, 0.01 to 40 atomic percent of Co, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 20
Dependent Claim
76 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 3.0 atomic percent of at least one element selected from the group consisting of Zr and Hf, 0.01 to 40 atomic percent of Co, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 21
Dependent Claim
70 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 5.0 atomic percent of at least one element selected from the group consisting of Al, Si and V, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 22
Dependent Claim
77 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material contains 8 to 30 atomic percent of R, 3 to 15 atomic percent of B, 0.01 to 40.0 atomic percent of Co, 0.01 to 5.0 atomic percent of at least one element selected from the group consisting of Al, Si and V, balance Fe and unavoidable impurities, wherein R represents a rare earth element.
Claim 23
Dependent Claim
40 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said alloy material is in the form selected from the group consisting of crushed ingots, bulk material, flakes and powder.
Claim 24
Dependent Claim
35 words
A method for producing a rare earth permanent magnet powder according to claim 6, claim 7 or claim 8, wherein said regenerative material is a material having a melting point higher than said alloy material.
Claim 25
Dependent Claim
28 words
A method for producing a rare earth permanent magnet powder according to claim 21, wherein said regenerative material is selected from the group consisting of ceramics and metal.
Claim 26
Dependent Claim
165 words
A bonded magnet produced by the steps of: preparing a R-Fe-B permanent magnet powder which comprises particles each containing 10 to 20 atomic percent of R, 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R2Fe, a B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20u.m, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain; and blending said magnet powder with a resin and pressing the blended powder to provide the bonded magnet.
Claim 27
Dependent Claim
165 words
A bonded magnet produced by the steps of: preparing a R-Fe-B permanent magnet powder which comprises particles each containing 10 to 20 atomic percent of R, 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R2Fe, a B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20u.m, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain; and blending said magnet powder with a resin and pressing the blended powder to provide the bonded magnet.
Claim 28
Dependent Claim
218 words
A bonded magnet produced by the steps of: preparing a R-Fe-Co-B permanent magnet powder which comprises particles each containing 10 to 20 atomic percent of R, 0.1 to 50 atomic percent of Co, 3 to 20 atomic percent of B, 0.001 to 5.0 atomic percent of at least one element selected from the group consisting of Ga, Zr and Hf, balance Fe and unavoidable impurities, wherein R represents a rare earth element, said individual particle comprising an aggregated structure of recrystallized grains containing a R 2 (Fe,C O ) 14 B intermetallic compound phase of a tetragonal crystal structure as a principal phase, wherein said recrystallized grains of said aggregated structure have an average crystal grain size of 0.05 to 20u.m, and wherein at least 50% by volume of said recrystallized grains of said aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain; and blending said magnet powder with a resin and pressing the blended powder to provide the bonded magnet. 25. A rare earth permanent magnet powder according to claim 23 or claim 24, wherein a part of Fe is substituted by 0.01 to 2.0 atomic percent of at least one element selected from the group consisting of Al, V and Si.
Claim 29
Dependent Claim
30 words
A rare earth permanent magnet powder according to claim 23, claim 24 or claim 25, wherein the average crystal grain size of the recrystallized grains ranges from 0.05 to 3u.m.
Claim 30
Dependent Claim
26 words
A rare earth permanent magnet powder according to claim 26, in which said aggregated structure essentially consists of the recrystallized grains of said intermetallic compound phases.
References Cited (Backward Citations)
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