MAGNET AND PROCESS FOR MANUFACTURING NdfeB MAGNETS FROM HYDROGENATED POWDERS

The invention relates to a process for manufacturing magnets from NdFeB, from hydrogenated powders with a mixture of Dy2O3 or/and DyFeAl prepared by decrepitation with hydrogen in two thermal stages: at approximately 170 degree C and at 500 degree C dehydrogenating, pressing and sintering said powders at a temperature ranging from 1050...1100 degree C and by tempering/annealing/drawing back in protective atmosphere at approximately 630 degree C, the cycle of the decrepitation and dehydrogenation phases being taken again after the first sinterization, before mixing with powders of Dy, the final sinterization and magnetization, and also to a magnet prepared by this process, having high characteristics concerning the intrinsic coercive force and maximal temperature of using. Inventia se refera la un procedeu de realizare a magnetilor din NdFeB, din pulberi hidrogenate cu amestec de pulberi de Dy2 O3 sau/si DyFeAl, obtinute prin decrepitare cu hidrogen in doua trepte termice: la circa 170 degree C si la 500 degree C, carora li se aplica tratamente de: dehidrogenare, presare, sinterizare la 1050...1100 degree C si revenire in atmosfera protectoare la circa 630 degree C, ciclul fazelor de decrepitare si dehidrogenare fiind reluat dupa prima sinterizare, inainte de amestecare cu pulberi de Dy, sinterizarea finala si magnetizare, precum si la un magnet obtinut cu acest procedeu, cu caracteristici superioare privind campul coercitiv intrinsec si temperatura maxima de utilizare.