High Resolution Electron Microscopy of Grain Boundaries in Sintered Fe77Nd15B8 Permanent Magnets

Publisher Website
Google Scholar
Abstract
Grain boundaries of sintered Fe77Nd15B8 permanent magnets with different heat-treatments have been examined by high resolution electron microcopy. A b.c.c. phase with the lattice constant of a=0.29 nm was found at most of the boundaries of Fe14Nd2B grains. The b.c.c. phase and Fe14Nd2B grains are joined with smooth interfaces in the samples annealed at 870 K, which have a coercivity as high as 1000 KA/m. In samples quenched from 1350 K with a coercivity of about 500 KA/m, however, thin plates of the b.c.c. phase extend from the interfaces to the inside of the Fe14Nd2B grains, and deform the lattice spacings of (001) planes of the Fe14Nd2B matrix. These thin plates are considered to act as nucleation centers of reverse magnetic domains which reduce the coercivity of the specimen.

This publication has 2 references indexed in Scilit: