Large grain cobalt-samarium intermetallic permanent magnet material stabilized with zinc and process

Abstract

Abstract AN ALLOY OF COBALT AND SAMARIUM IS CAST TO PRODUCE A CAST BODY HAVING GRAINS RANGING IN SIZE FROM ABOUT 100 MICRONS TO 1000 MICRONS. THE CAST BODY IS ANNEALED IN AN ATMOSPHERE IN WHICH IT IS SUBSTANTIALLY INERT AT A TEMPERATURE RANGING FROM ABOUT 900*C. UP TO A TEMPERATURE BELOW ITS MELTING POINT FOR A PERIOD OF TIME RANGING FROM ABOUT 5 MINUTES TO 24 HOURS. TO GET SIGNIFICANTLY USEFUL PERMANENT MAGNET PROPERTIES, IT SHOULD BE ANNEALED AT A PARTICULAR ANNEALING TEMPERATURE FOR A PERIOD OF TIME SUFFICIENT FOR THE RESULTING FREE GRAINS TO SHOW AT ROOM TEMPERATURE, AFTER BEING MAGNETIZED TO AT LEAST APPROACH SATURATION MAGNETIZATION, A RELATIVE MAGNETIZATION VALUE OF AND/OR OF AT LEAST 50 PERCENT AT A DEMAGNETIzING FIELD OF -4 KILOOERSTEDS WITH RELATIVE MAGNETIZATION 4NJBR, BY DEFINITION, BEING 1,00 AT ZERO DEMAGNETIZING FIELD. THE ANEALED BODY IS THEN COMMINUTED TO A GRAIN SIZE CORRESPONDING TO OR SMALLER THAN THE GRAIN SIZE OF THE CAST BODY AND RANGING FROM ABOUT 50 MICRONS TO 200 MICRONS. THE FREE ANNEALED GRAINS ARE AMIXED WITH 1-15% BY WEIGHT ZINC POWDER AND THE RESULTING MIXTURE IS HEATED TO MELT THE ZINC POWDER TO FORM A CONTINOUS COATING OF ZINC ON THE INDIVIDUAL GRAINS.

Inventors

• 👤 M Benz

Bibliographic Details