R-T-B based permanent magnet
AssigneeTDK Corporation
InventorsAtsushi Koda, Takahiro Suwa, Hikaru Kudo
Life of this patent
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Abstract
An R-T-B permanent magnet that contains: main-phase grains composed of an R2T14B compound (where R is a rare earth element, T is a transition metal element, and B is boron); and grain boundaries. R includes Ce. The grain boundaries include multi-grain grain boundaries that are adjacent to three or more main-phase grains. The multi-grain grain boundaries include an R-rich phase, and lamellar or acicular R-T precipitates are present in the R-rich phase.
Claims17
An R-T-B based permanent magnet comprising main phase grains including an R2T14B (compound, in which R includes a rare earth element, T includes a transition metal element, and B represents) boron, and a grain boundary, wherein
- R at least includes Ce,
- the grain boundary includes a grain boundary multiple junction surrounded by three or more main phase grains, and
- the grain boundary multiple junction includes an R-rich phase, the R-rich phase includes an R-T deposit of a plate shape or a needle shape, and 30.0% or more of the circumference of the R-T deposit is covered in the R-rich phase in one cross-section of the R-T-B based permanent magnet.
Dependencies are inferred from the claim text.