Compositions – Magnetic – Free metal or alloy containing
Patent
1996-11-05
2000-11-07
Sheehan, John
Compositions
Magnetic
Free metal or alloy containing
148301, 148302, B22F 300
Patent
active
061431931
ABSTRACT:
A rare earth bonded magnet comprising a rare earth magnet powder bonded with a binder resin is manufactured by extrusion or injection molding. A rare earth bonded magnet manufactured by extrusion molding has a rare earth magnet powder content of 78.1 to 83.0 percent by volume. A rare earth bonded magnet manufactured by injection molding has a rare earth magnet powder content of 68.0 to 76.0 percent by volume. Preferably, the rare earth metal powder is at least one of Sm--Co alloys, R--Fe--B alloys wherein R is at least one of rare earth elements including Y, and Sm--Fe--N alloys. Preferably, the thermoplastic resin include polyamide, liquid crystal polymer, and Polyphenylene sulfide. Preferably, the rare earth bonded metal has a void ratio of 2 percent by volume or less. A rare earth bonded magnet is manufactured by kneading a rare earth magnetic composition comprising a rare earth magnet powder and a thermoplastic resin, and by extruding or injecting the mixture after kneading. A rare earth magnetic composition used for extrusion molding contains a rare earth metal powder of 77.6 to 82.5 percent by volume, and a rare earth magnetic composition used for injection molding contains a rare earth metal powder of 67.6 to 75.5 percent by volume. Preferably, such rare earth magnetic compositions further comprise an antioxidant, such as a chelating agent. Thus, a rare earth bonded magnet showing excellent moldability and magnetic properties and high mechanical strength at a minimum binding resin can be obtained.
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Akioka Koji
Ikuma Ken
Nakamura Yoshiki
Shirai Hayato
Takei Mitsuru
Seiko Epson Corporation
Sheehan John
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