Patent Number: 7,087,185

Title: Magnetic powder and isotropic bonded magnet

Abstract: Disclosed herein is a magnetic powder which can provide a magnet having a high magnetic flux density and excellent magnetizability and reliability especially excellent heat resisting property (heat stability). The magnetic powder is composed of an alloy composition represented by R.sub.x(Fe.sub.1-yCo.sub.y).sub.100-x-z-wB.sub.zAl.sub.w (where R is at least one kind of rare-earth element, x is 8.1 9.4 at %, y is 0 0.30, z is 4.6 6.8 at %, and w is 0.02 1.5 at %), the magnetic powder being constituted from a composite structure having a soft magnetic phase and a hard magnetic phase, wherein the magnetic powder has characteristics in which, when the magnetic powder is formed into an isotropic bonded magnet by mixing with a binding resin and then molding it, the irreversible susceptibility (.chi..sub.irr) which is measured by using an intersectioning point of a demagnetization curve in the J-H diagram representing the magnetic characteristics at the room temperature and a straight line which passes the origin in the J-H diagram and has a gradient (J/H) of -3.8.times.10-.sup.6 H/m as a starting point is less than 5.0.times.10-.sup.7 H/m, and the intrinsic coercive force (H.sub.CJ) of the magnet at the room temperature is in the range of 406 717 kA/m.

Inventors: Arai; Akira (Shimosuwa-machi, JP), Kato; Hiroshi (Okaya, JP)

Assignee: Seiko Epson Corporation

International Classification: H01F 1/26 (20060101)

Expiration Date: 8/08/02018