IMPROVEMENT OF THERMAL-STABILITY OF ND-DY-FE-CO-B SINTERED MAGNETS BY ADDITIONS OF AL, NB AND GA

To improve the thermal stability of (Nd//0//. //8Dy//0//. //2) (Fe//0//. //8//6Co//0//. //0//6B//0//. //8)5. 5 sintered magnets for heavy duty applications, such as starter motors, effects of additional elements (M equals Al, Nb and Ga) on the thermal stability were investigated in the (Nd//0//. //8Dy//0//. //2) (Fe//0//. //6// minus //uCo//0//. //6B//0//. //0//8Mu)5. 5 sintered magnets. The addition of Al increased //iH//c, but did not decrease irreversible losses at 220 degree C (Pc equals 2). The sintered magnet with M equals Nb and u equals 0. 0006 had lower //iH//c and higher irreversible losses than u equals 0, while the sintered magnet with M equals Nb and u equals 0. 015 and higher //iH//c and lower irreversible losses. A combination of both Nb and Ga additions was also studied.