R-t-b based permanent magnet
AssigneeTDK Corporation
InventorsHidetake KITAOKA, Makoto IWASAKI
Life of this patent
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Abstract
An R-T-B based permanent magnet in which R is a rare earth element, T is Fe or a combination of Fe and Co, B is boron, and further includes M. The R-T-B based permanent magnet includes main phase grains consisting of R2T14B phase. M at least includes Ga and Zr. The R-T-B based permanent magnet further includes C and O. R content is 29.0 mass % to 33.0 mass %, B content is 0.85 mass % to 1.05 mass %, Ga content is 0.30 mass % to 1.20 mass %, 0 content is 0.03 mass % to 0.20 mass %, and C content is 0.03 mass % to 0.30 mass %. Further, the R-T-B based permanent magnet satisfies 3.48 m(B)−2.67≤m (Zr)≤3.48 m(B)−1.87 in which m (B) (mass %) is B content and m (Zr) (mass %) is Zr content.
Claims20
An R-T-B based permanent magnet comprising C, 0, and M, wherein
- R is a rare earth element, T is Fe or a combination of Fe and Co, B is boron,
- M includes at least Ga and Zr, and further includes at least one element selected from Al, Si, P, Ti, Cr, Mn, Ni, Cu, Zn, Ge, Nb, Ag, In, Sn, Sb, Hf, Ta, W, and Bi,
- R content is 29.0 mass % to 33.0 mass %,
- B content is 0.85 mass % to 1.05 mass %,
- Ga content is 0.30 mass % to 1.20 mass %,
- O content is 0.03 mass % to 0.20 mass %,
- C content is 0.03 mass % to 0.30 mass %,
- where the R-T-B based permanent magnet is 100 mass %, and
- the R-T-B based permanent magnet satisfies
- 3.48m(B)−2.67≤m(Zr)≤3.48m(B)−1.87
- in which m (B) (mass %) is B content and m (Zr) (mass %) is Zr content.
Dependencies are inferred from the claim text.