Inhomogeneity on texture, microstructure and magnetic properties of hot deformed R2Fe14B-typed magnet

摘要

The inhomogeneity on texture, microstructure and magnetic properties of hot deformed (HD) disc shape R2Fe14B-typed magnets along radial and axial directions has been investigated. HD disc shape NdFeB magnet exhibits inhomogeneous texture, grain morphologies and magnetic properties not only along the radial direction but also along the axial direction. Higher magnetic properties can be found in the middle part of the HD magnet, due to the existence of larger volume fraction of plate-like Nd2Fe14B grains and the well c-axis alignment parallel to the pressing direction. In addition, particle-like and coarser grains are easily found not only in the bottom but also in the edge of the HD magnet, which may degrade the magnetic performance of the samples cut from those parts. Owing to the inhomogeneity of (00L) texture and grain morphologies along axial and radial directions, the optimal magnetic properties of B-r = 12.7 kG, H-ci = 5.1 kOe and (BH)(max) = 39 MGOe can be obtained only in the middle sample of HD magnet with slight polishing the top and bottom surfaces.