Nd_2Fe_(17) nanograins effect on the coercivity of HDDR NdFeB magnets with low boron content

摘要

Relationships between the coercivity of hydrogenation disproportionation desorption recombination(HDDR) Nd12.5Fe81.5-xCo6Bx bonded magnets and boron content were investigated.Nd2Fe17 phase with planar magnetic anisotropy is present in the microstructure when x= 4at%-5.88at%,which does not reduce the coercivity of the bonded magnets.High-resolution transmission electron microscopy(TEM) images show that Nd2Fe17 phase exists in the form of nanocrystals in the Nd2Fe14B matrix.There is an exchange-coupling interaction between the two phases so that the coercivity of HDDR Nd12.5Fe81.5-xCo6Bx bonded magnets is hardly reduced with a decrease in boron content.