The effect of cobalt content on the microstructure of Pr-Fe-Co-B-Nb alloys and magnetic properties of HDDR magnets

This paper reports the results of investigations carried out to determine the microstructure and magnetic properties of some cast and homogenized praseodymium-based alloys and magnets represented by the formula Pr14Fe79.9-xCoxB6Nb0.1. Permanent magnets were prepared from cast and annealed alloys using the hydrogenation, disproportionation, desorption and recombination process. The effect of cobalt content on the magnetic properties of these magnets was investigated. Cobalt has a significant effect on the magnetic behaviour of these alloys. Microstructural examinations revealed that the grain size of the matrix phase increased with increasing cobalt content in the Pr-based alloys and niobium had a grain-refining role