Improvement of coercivity of sintered NdFeB permanent magnets by heat treatment

The purpose of this study was to better understand the metallurgical transformations that occur during beat treatment of Nd-based magnets. DSC analysis and microstructural investigations of the grain boundaries with SEM and TEM were carried out, DSC permitted to optimize the heat treatment. Microstructural investigations always showed the presence of thin and smooth RE-rich film, associated with the highest coercivity. (C) 2002 Elsevier Science B.V. All rights reserved.