Magnet powders and isotropic rare-earth bonded magnets

摘要

Disclosed herein is a magnet powder which can provide a magnet having a high magnetic flux density and excellent magnetizability and reliability. The magnet powder is composed of an alloy composition represented by Rx(Fe1- yCoy)100-x-z-wBxAlw (where R is at least one kind of rare-earth element, x is 8.1 - 9.4at%, y is 0 - 0.30, z is 4.6 - 6.8at%, and w is 0.02 - 0.8at%), and it has a structure in which a soft magnetic phase (10) and a hard magnetic phase (11) exist adjacent with each other. The magnet powder has characteristics in which, when an isotropic bonded magnet is molded by mixing the magnet powder with a binding resin, the magnetic flux density (B) of the bonded magnet, in the region of B higher than the straight line for Pc (permeance coefficient) = 2.0 in the second quadrant of the B-H diagram representing the magnetic characteristics at room temperature, is found always on the upper side of the straight line representing Equation (I) below, and the intrinsic coercive force (iHc) of the magnet is in the range of 5.1 - 9.0kOe: $where\; B\; is\; the\; magnetic\; flux\; density,\; rho\; is\; the\; density\; of\; the\; bonded\; magnet,\; and\; H\; is\; the\; magnetic\; field.\mathop{\mathrm{image}}$