Improvement of comprehensive magnetic properties for hot-deformed NdFeB magnets via intergranular additions of nano-TiC

After mixing NdFeB melt-spun ribbons and nano-TiC powders, the latter broke ribbons into fine particles. More nanoscale dopants led to finer NdFeB particles during powder extrusion. It made liquid Nd-rich phases to be easily squeezed from the ribbon interior and the matrix phase grain boundaries into the interspaces of ribbon interface during hot pressing and deformation. Such facts benefited the orientation degree of matrix phase and the magnetic performance of hot-deformed magnets. [Display omitted] •Doping nano-TiC increased comprehensive magnetic properties of hot-deformed NdFeB.•Nano-TiC broke NdFeB ribbons into fine particles, increasing strip-shaped Nd-rich phase.•More strip-shaped Nd-rich phase benefited orientation degree of matrix phase. Intergranular doping nano-TiC was used to enhance the comprehensive magnetic properties of hot-deformed NdFeB. Before 1.0 wt% more dopants increased the amount of strip-shaped Nd-rich phases at ribbon boundaries due to the ribbon fragmentation and the improved Nd2Fe14B orientation degree, raising the remanence. It coupled with better squareness enhanced the magnetic energy product (BH)max by 10.8% compared to the case of TiC-free. The increase of strip-shaped Nd-rich phases decreased the Nd-rich phases surrounded ultrafine matrix phase grains, reducing the magnetic isolation and harming the coercivity Hcj after 0.25 wt%. At the dopant range of 0.25–1.0 wt%, Hcj+(BH)max had almost the same values, higher than the corresponding value of TiC-free magnet, demonstrating that appropriate nano-TiC additions improved the magnetic performance.