R-t-b based permanent magnet
AssigneeTDK Corporation
InventorsMasashi MIWA, Takurou IWASA
Life of this patent
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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. An average grain size of the main phase grains is 0.8 μm or more and 2.8 μm or less. The R-T-B based permanent magnet contains at least C and Zr in addition to R, T, and B. B is contained at 0.75 mass % or more and 0.88 mass % or less. Zr is contained at 0.65 mass % or more and 5.00 mass % or less. A formula (1) of 5.0≦[B]+[C]−[Zr]≦5.6 is satisfied, where [B] is a B content represented by atom %, [C] is a C content represented by atom %, and [Zr] is a Zr content represented by atom %.
Claims14
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,
- an average grain size of the main phase grains is 0.8 μm or more and 2.8 μm or less,
- the R-T-B based permanent magnet contains at least C and Zr in addition to R, T, and B,
- B is contained at 0.75 mass % or more and 0.88 mass % or less,
- Zr is contained at 0.65 mass % or more and 5.00 mass % or less, and
- a formula (1) of 5.0≦[B]+[C]−[Zr]≦5.6 is satisfied, where [B] is a B content represented by atom %, [C] is a C content represented by atom %, and [Zr] is a Zr content represented by atom %.
Dependencies are inferred from the claim text.