An analysis of the magnetization behavior and temperature dependence of coercivity in hot deformed Nd2Fe14B magnets with different deformation degrees

Abstract

Hot deformation magnets with different height reductions are prepared following hot press process. The coercivity of the magnets decreases from 19.5kOe to 15.5kOe while the remanence increases from 8.5kGs to 13.5kGs. Minor loops of the hot pressed and deformation magnets are both measured to analyze the magnetization behaviors. The saturation magnetization vs. the maximum applied field of the hot pressed and deformation magnets are also carried out. The microstructures of these magnets are analyzed through scanning electron microscope (SEM). It can be obtained that the shape of the grains in these magnets changes into platelike when the height reductions get higher. The temperature dependences of the coercivity of the magnets are carried out. The nanostructural parameters which are related to different nanostructural effects are also obtained from the linear relationship between Hc/Ms and HA/Ms. In this paper, it is believed that the varieties of the coercivity is strongly dependant on the shape of the grains and the grain boundary structures.