CHARACTERIZATION OF EXCHANGE-SPRING MAGNETS OBTAINED BY SINTERING Nd-Fe-B POWDERS

SANTIAGO PRECKEL; LAURA PAMPILLO; FABIO SACCONE; MARCELO PAGNOLA

Centro Cultural Borges , Ciudad Autonoma de Buenos Aires, Argentina

Simposio; ISMANAM 2008; 2008

Facultad De Ingenieria. - CIDIDi

Exchange-spring magnets are composed by a hard magnetic phase mixed with a soft one. When these phases are intimately bound, the magnetic exchange interaction reinforces the remanence. By this reason, it is necessary to match the magnetic correlation length and the structural length. In order to get this, in the case of Nd-Fe-B magnets, it must be modified the composition to get away from the stoichiometic hard magnetic compound (Nd2Fe14B) and must be used rapid solidification techniques.  There are two different compositions that allow to obtain materials with optimal magnetic properties: Nd5Fe77B18 and Nd10Fe80B10 [1]. In this work we present structural and magnetic characterization of permanent magnets conformed by sintering Nd-Fe-B commercial powders SPRAX® (NEOMAX Co. Ltd.) of five different types labeled as SPRAX-XB, SPRAX-XC, SPRAX-XD and SPRAX-XE (namely X-Series) and SPRAX-C. The compacted pieces, of typically 0.5 cm diameter and 1 cm height, were sinterized in vacuum at 700ºC during 10 minutes. Similar analysis, as those detailed above, were performed to the sintered pieces.