IRON-BASED PERMANENT MAGNET, MANUFACTURE THEREOF AND IRON-BASED PERMANENT MAGNET ALLOY POWDER FOR BONDED MAGNET AND IRON-BASED BONDED MAGNET

摘要

PURPOSE: To provide an iron-based bonded magnet having a residual magnetic flux density Br of at least 5kG by allowing both a soft magnetic phase comprising a ferromagnetic alloy mainly composed of α-iron and iron and a hard magnetic phase having Nd2 Fe14 B type crystal structure to coexist dispersed with each other and setting the mean crystal grain size of each component layer to lie within a specific range. CONSTITUTION: The substance shown by the formula has the composition where: 0.01<=x<=7at%, 15<=y<=30at%, 3<=z<=6at%, 0.01<=a<=30at% where R is either Pr or Nd or both in the formula. The soft magnetic phase comprising a ferromagnetic alloy mainly composed of α-iron and iron is allowed to coexist with a hard magnetic phase having an Nd2 Fe14 B type crystal structure in the same powder. Furthermore, the mean crystal particle diameter of both substances is specified to range from 1nm to 30nm and both are dispersed with each other. This construction makes it possible to stabilize and supply large quantities of Fe-Cr-Co-B-R-M magnet alloy powder having the optimum magnetic properties to a bonded magnetic having a residual magnetic flux density Br which exceeds 5kG.