STUDIES ON LOW RARE-EARTH ND-FE-B COMPOSITIONS

Investigations have been carried out to evaluate the optimum Nd-Fe-B c omposition to have H-ci of at least 4 kOe. The otpimum composition for the best magnetic properties is as follows: TRE 18 wt. %, B 1 wt. % a nd balance Fe. The magnetic I,roperties are B-r, 10.1 kG, H-ci 4.3 kOe and BHmax 12.5 MGOe. All the additives (Ga, Nb, Mo, V, Cr) with or wi thout cobalt addition did not improve the magnet properties. The bonde d magnets made using this material had B-r value slightly higher than the standard MQP-B powder. The low coercivity of these materials limit their operating temperature to 80 degrees C. This material having Nd2 Fe14B/proportional to-Fe structure shows improved saturation behavior compared to those having Nd2Fe14B/Fe3B and Nd2Fe14B structures. It wou ld then be a good candidate for applications where magnetization is di fficult.