Coercitivity of (PrDy)(CoFe)B Microparticles Ensemble Controlled by Magnetic Dipole Interaction and Dry Friction

(DyPr)CoFeB microparticles are the building blocks of sintered magnets. The magnetic properties of powdered (DyPr)(CoFe)B microparticles and the effects of annealing, surface states, fixation of easy axis and magnetic dipole interaction on the magnetic hysteresis loop, and temperature dependencies of magnetization have been analyzed. Fixation of the annealed microparticles in polymer enhances the coercive field up to 11 times and the energy product up to six times. This fact indicates extraction of the true magnetic parameters from the magnetic measurements of powder. Thermal stability of the anisotropy field has been improved by the replacement of Fe atoms with Co atoms.