Permanent magnet
AssigneeTDK Corporation
InventorsMasaki Tomita, Ryuji Hashimoto, Takashi Watanabe
Life of this patent
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Abstract
A permanent magnet including R and T. R are rare earth elements including Sm and at least one selected from Y and Gd. T is Fe alone or Fe and Co. T maybe partly substituted with M, and M is one or more selected from Ti, V, Cr, Mo, W, Zr, Hf, Nb, Ta, Al, Si, Cu, Zn, Ga and Ge. In a total content of R, Sm content is 60 at % or more and 95 at % or less, and a total content of Y and Gd is 5 at % or more and 35 at % or less. The permanent magnet includes main phase crystal grains having a ThMn12 type crystal structure.
Claims8
A permanent magnet comprising R and T, wherein R are rare earth elements comprising Sm and at least one selected from Y and Gd,
- T consists of Fe or Fe and Co,
- Sm content is 60 at % or more and 95 at % or less with respect to a total content of R and a total content of Y and Gd is 5 at % or more and 35 at % or less with respect to the total content of R,
- the permanent magnet comprises main phase crystal grains having a ThMn12 type crystal structure, and
- an area ratio of the main phase crystal grains satisfying 0.1 μm≤Dv≤10 μm and 0.7≤(Di/Dv)≤2.0 is 70% or more,
- where a grain size of each of the main phase crystal grains is Di and an average grain size of the main phase crystal grains is Dv in a cut section obtained by cutting the permanent magnet.
A permanent magnet comprising R and T, wherein R are rare earth elements comprising Sm and at least one selected from Y and Gd,
- T consists of Fe or Fe and Co,
- T is partly substituted with M,
- M is one or more selected from Ti, V, Cr, Mo, W, Zr, Hf, Nb, Ta, Al, Si, Cu, Zn, Ga and Ge, and
- Sm content is 60 at % or more and 95 at % or less with respect to a total content of R and a total content of Y and Gd is 5 at % or more and 35 at % or less with respect to the total content of R,
- the permanent magnet comprises main phase crystal grains having a ThMn12 type crystal structure, and
- an area ratio of the main phase crystal grains satisfying 0.1 μm≤Dv≤10 μm and 0.7≤(Di/Dv)≤2.0 is 70% or more,
- where a grain size of each of the main phase crystal grains is Di and an average grain size of the main phase crystal grains is Dv in a cut section obtained by cutting the permanent magnet.
Dependencies are inferred from the claim text.