Coercivity of Nd(Dy)-Fe-B bonded magnets made from the inert-gas-atomized powders

The coercivity behaviour of bonded magnets made from sieved inert-gas-atomized Nd(Dy)-Fe-B powders has been investigated. For magnets with particle sizes 35-53 mu m, the coercivity is controlled by a nucleation mechanism as in the sintered magnet. For the magnet with particle sizes of 10-20 mu m, the hardening mechanism is mainly controlled by nucleation as in the sintered magnet but the hardening mechanism of domain wall pinning or the nucleation of a single domain, which usually appears in melt-spun materials, may also be involved. The coercivity behaviour of bonded magnets made from gas-atomized powders seems to be between those of the sintered and melt-spun magnets depending on the particle size. Meanwhile it has been found that the demagnetizing field of bonded magnets made from the inert-gas-atomized powders is very small.