The influence of alloying additions and process parameters on the magneticproperties of PrFeB-based bonded magnets

The effects of Co,Zr, Nh, Ga and Dy additions upon the magnetic properties of PrFeB-based alloys have been studied. Bonded magnets have been prepared from as-cast and homogenised alloys using an optimised hydrogenation dispro portionation desorption and recombination (HDDR) process. In general, the H DDR bonded magnets from homogenised alloys exhibited higher remanence (B-r) , squareness factor (SF) and intrinsic coercivity (H-i(c)). In particular, the Pr13.7Fe63.5Co16.7B6Nb0.1 HDDR magnet exhibited the best overall magnet ic properties (B-r=1032+/-20 mT, H-i(c)=793+/-20 kA/m and SF=0.51), indicat ing that Co and Nb additions, in these proportions have a beneficial effect on PrFeB-based magnets. Conversely, additions of Ga and Dy were observed t o dramatically reduce the intrinsic coercivity of Pr-based HDDR magnets. (C ) 2000 Elsevier Science S.A. All rights reserved.