Improvement of Intrinsic Coercivity in HDDR-processed Anisotropic Permanent Magnets

High-coercivity anisotropic Nd-Fe-B magnet powder of H sub cJ =1.24MA/m has been developed in HDDR process by substituting Dy for Nd to decrease the value of irreversible thermal flux losses. The newly developed powder provides lower irreversible thermal losses than MQP-B up to 100 deg C when molded into resin-bonded magnets. The magnets made from the high-H sub cJ powder give higher relative open flux when magnetized under a magnetization field of 1.2MA/m at 80 deg C than magnetized at 20 deg C. To magnetize these magnets at high temperature also decreases the value of irreversible thermal flux losses.