R-t-b based permanent magnet
AssigneeTDK Corporation
InventorsMasashi MIWA, Takurou IWASA, Tamotsu ISHIYAMA
Life of this patent
Estimating the term…
Abstract
An R-T-B based permanent magnet includes main phase grains composed of R2T14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. The magnet contains at least C, Ga, and M selected from Zr, Ti, and Nb in addition to R, T, and B. B is contained at 0.71 mass % to 0.88 mass %. C is contained at 0.15 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.40 mass %. M is contained at 0.25 mass % to 2.50 mass %. A formula (1) of 0.14≦[C]/([B]+[C])≦0.30 and a formula (2) of 5.0≦[B]+[C]−[M]≦5.6 are satisfied, where [B], [C], and [M] are respectively a content of B, C, and M by atom %.
Claims12
An R-T-B based permanent magnet comprising main phase grains composed of R2T14B type compound, wherein
- R is a rare earth element, T is iron group element(s) essentially comprising Fe or Fe and Co, and B is boron,
- the R-T-B based permanent magnet contains at least C, Ga, and M (M is at least one kind selected from a group of Zr, Ti, and Nb) in addition to R, T, and B,
- B is contained at 0.71 mass % or more and 0.88 mass % or less,
- C is contained at 0.15 mass % or more and 0.34 mass % or less,
- Ga is contained at 0.40 mass % or more and 1.40 mass % or less,
- M is contained at 0.25 mass % or more and 2.50 mass % or less, and
- a formula (1) of 0.14≦[C]/([B]+[C])≦0.30 and a formula (2) of 5.0≦[B]+[C]−[M]≦5.6 are satisfied, where [B] is a B content represented by atom %, [C] is a C content represented by atom %, and [M] is a M content represented by atom %.
Dependencies are inferred from the claim text.