Phase transformation-induced coercivity mechanism in rare earth sintered magnets

Abstract

The phase transformation-induced coercivity mechanism in Sm Co5±x sintered magnets is proposed based on the phase transformations according to the hypothetic Sm-Co phase diagram. The phase transformations are supposed to modify the surface of principal phase grains. The precipitation of the Sm Co5-x phases in Sm-rich magnets and the Sm2 Co17 phase in Co-rich magnets at grain boundaries of the principal Sm Co5 phase leads to the smoothing out of the grain surface and, thus, coercivity increases. © 2006 American Institute of Physics.