High coercivity anisotropic Nd_2Fe_(14)B nanoparticles for the development of high-energy nanocomposite magnets

摘要

This paper reports on a study conducted for the production of anisotropic Nd_2Fe_(14)B nanoparticles using surfactant-assisted high-energy ball milling (SA-HEBM). Our results show that the generation of nanoparticles can be accomplished in a relatively short milling time, while maintaining the optimum magnetic properties. Powders have been produced from the MQIII precursor over a range of different milling times. These treatments generated particles with wide size distributions, which were separated by filter paper with a pore size of 0.02 μm. The magnetic properties of these powders have been determined using VSM, which enabled a particular milling treatment to be selected for the production of nanoparticles with desired magnetic properties. For the SA-HEBM, the nanoparticles consisted of a mixture of Nd_2Fe_(14)B plate-like particles with the thickness below 100 nm. Room temperature coercivities have been obtained with the maximum values of 12.6 kOe for irregular plate-like nanoparticles. This study shows that the production of Nd-Fe-B plate-like anisotropic nanoparticles formed by SA-HEBM could provide an effective method for the development of anisotropic nanocomposite permanent magnets. Work supported by DOE ARPA-E