Patent ID: 7087185

Claim:
An isotropic rare-earth bonded magnet comprising: a magnetic powder having an alloy composition represented by Rx(Fe 1-y Co y ) 100-x-z-w B z Al w (where R is at least one rare-earth element, x is 8.1–9.4 at %, y is 0.0–0.30 at %, 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 hard magnetic phase; and a binding resin; wherein the soft magnetic phase and the hard magnetic phase have a mean crystal grain size in the range of 1–100 nm; and the isotropic rare-earth bonded magnet is characterized in that the irreversible susceptibility (χ irr ), which is measured by using an intersectioning point of a demagnetization curve in a J-H diagram representing magnetic characteristics at room temperature and a straight line which passes an origin in the J-H diagram and has a gradient (J/H) of −3.8×10 −6 H/m as a starting point is less than 5.0×10− 7 H/m, and the intrinsic coercive force (H CJ ) of the magnet at the room temperature is in the range of 406–717 kA/m.