MICROSTRUCTURAL ANALYSIS OF FE-ND-C-B TYPE INGOT MAGNETS

The microstructure of ingot Fe-Nd-C-B type magnets has been studied by transmission electron microscopy. It has been found that the hard mag netic Fe14Nd2C grains, having mean diameter of approximate to 10 mu m, contain colonies of 20 nm diameter precipitates. The precipitates do not prove to act as centres for magnetic domain wall pinning. Elastic strain produced by solidification of the Nd-rich phase after heat trea tment is considered to be a source of the structural defects observed in the hard magnetic grains. The dislocation systems in the material m ay affect the deformation mechanism leading to the processing of aniso tropic magnets.