MAGNETIC PROPERTIES AND MICROSTRUCTURES OF THE Nd-Fe-B SYSTEM BY HDDR PROCESS

This paper concentrates on the technological conditions on fabrication of isotropic and anisotropic Nd-Fe-B by HIIDDR process. The XRD patterns were studied by using X-ray diffraction. The change of the particle size and morphology of powders were investigated by scanning electron microscopy (SEM). In order to study the effects of contents and temperature on the properties of the magnetic powders, different compounds with different contents (Nd10Fe83B7, Nd16Fe77B-, and Nd22Fe71 B7 for isotropy and Nd1 6Fe65Co1 2B7, Nd1 6Fe76?B7Zr0 and Nd16Fe649Co12Zr01B7 for anisotropy) were prepared and treated at 650 0C, 700 0C, 7500C, 8O0~C and 8500C.During the I-IDDR process, the Nd2Fe14B phase was firstly decomposed into NdH2, a -Fe and Fe2B at 650 . And after the following process of desorption and recombination, NdH2, a -Fe and Fe2B were recombinated into Nd2Fe14B with a smaller particle size. With a small addition of Co and Zr, the increase of remanent polarization and enhancement in anisotropy were achieved.