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US 8,012,269 B2Granted
Nd-Fe-B rare earth permanent magnet material
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsKenji Yamamoto, Koichi Hirota, Takehisa Minowa
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Abstract
A rare earth permanent magnet material is based on an R—Fe—Co—B—Al—Cu system wherein R is at least one element selected from Nd, Pr, Dy, Tb, and Ho, 15 to 33% by weight of Nd being contained. At least two compounds selected from M-B, M-B—Cu and M-C compounds (wherein M is Ti, Zr or Hf) and an R oxide have precipitated within the alloy structure as grains having an average grain size of up to 5 μm which are uniformly distributed in the alloy structure at intervals of up to 50 μm.
Claims11
A rare earth permanent magnet material consists essentially of, in % by weight:
- 27 to 33% of R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Tb, and Ho, including 15 to 33% by weight of Nd,
- 0.1 to 10% of Co,
- 0.8 to 1.5% of B,
- 0.05 to 1.0% of Al,
- 0.02 to 1.0% of Cu,
- 0.02 to 1.0% of an element selected from Ti, Zr and Hf,
- 0.123 to 0.3% of C,
- 0.04 to 0.4% of O,
- 0.002 to 0.1% of N, and
- the balance of Fe and incidental impurities,
- wherein (i) at least two compounds selected from the group consisting of an M-B based compound, an M-B—Cu based compound, and an M-C based compound, wherein M is at least one metal selected from the group consisting of Ti, Zr, and Hf, and
- (ii) an R oxide have precipitated within the alloy, and the precipitated compounds have an average grain size of up to 5 μm and are distributed in the alloy at a maximum interval of up to 50 μm between adjacent precipitated compounds.
9 more elements
Dependencies are inferred from the claim text.