Microstructure and Properties of Magnets Obtained by Hydrostatic Extrusion of Nd-Fe-B Powder
T. Gizynskia, W. Kaszuwara a, P. Pawlik b, M. Kulczyk c, M. Leonowicz a and B. Michalski a
aWarsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw, Poland
bCzęstochowa University of Technology, Institute of Physics, al. Armii Krajowej 19, 42-200 Częstochowa, Poland
cInstitute of High Pressure Physics, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw, Poland
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Nd-Fe-B MQ powder was initially densified in a copper capsule to reach about 60% of the theoretical density. Subsequently, three various processes of hydrostatic extrusion were conducted at room temperature. The values of true strain, obtained during the all three stages, were 1.38, 0.89, 0.94, respectively. The investigation performed showed that the coercivity of the material decreases as the strain increases. Decrease of the remanence was observed only for the highest strains. Size of the particles was strongly reduced during the extrusion processes. X-ray diffraction did not show changes in the phase structure of the material. The Mössbauer study, of the sample extruded within all the three stages, showed existence of the Nd2Fe14B phase and 16% of other phase. Analysis of magnetization versus temperature confirmed that the additional phase was ferromagnetic.

DOI: 10.12693/APhysPolA.127.626
PACS numbers: 75.50.Ww