Rare earth permanent magnet, making method, and permanent magnet rotary machine
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsKoji Miyata, Koichi Hirota, Hajime Nakamura, Takehisa Minowa
Life of this patent
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Abstract
A rare earth permanent magnet is prepared from a sintered magnet body of a R1—Fe—B composition wherein R1 is a rare earth element inclusive of Y and Sc, by forming a plurality of slits in a surface of the magnet body, disposing a powder on the magnet body surface, the powder comprising an oxide of R2, a fluoride of R3, or an oxyfluoride of R4 wherein each of R2, R3, and R4 is a rare earth element, and heat treating the magnet body and the powder below the sintering temperature in vacuum or in an inert gas.
Claims17
A method for preparing a rare earth permanent magnet from a sintered magnet body of a R1—Fe—B composition wherein R1 is at least one element selected from among rare earth elements inclusive of Y and Sc, the method comprising the steps of:
- forming a plurality of slits in at least one surface of the magnet body,
- disposing a powder on the magnet body surface, the powder comprising at least one compound selected from among an oxide of R2, a fluoride of R3, and an oxyfluoride of R4 wherein each of R2, R3, and R4 is at least one element selected from among rare earth elements inclusive of Y and Sc, and
- heat treating the magnet body and the powder at a temperature equal to or below the sintering temperature of the magnet body in vacuum or in an inert gas, wherein
- the formation of the slits facilitates absorption of at least one of R2, R3 and R4 in the magnet body from the powder comprising at least one of the oxide of R2, fluoride of R3, and oxyfluoride of R4 present on the magnet surface, thereby increasing a coercive force.
Dependencies are inferred from the claim text.