Magnetic core comprising a bond magnet including magnetic powder whose particle's surface is coated with oxidation-resistant metal

摘要

Disposed in a magnetic gap of a magnetic core, a magnetically biasing permanent magnet is a bond magnet comprising rare-earth magnetic powder and a binder resin. The rare-earth magnetic powder has an intrinsic coercive force of 5kOe or more, a Curie temperature of 300 DEG C or more, and an average particle size of 2.0-50 mu m. The rare-earth magnetic power has a surface coated with a metallic layer containing an oxidation-resistant metal. In order to enable a surface-mount to reflow, the rare-earth magnetic powder may have the intrinsic coercive force of 10kOe or more, the Curie temperature of 500 DEG C and the average particle size of 2.5-50 mu m. In addition, to prevent specific resistance from degrading, the metallic layer desirably may be coated with a glass layer consisting of low-melting glass having a softening point less than a melting point of the oxidation-resistant metal.