Rapid sintering of anisotropic, nanograined Nd–Fe–B by flash-spark plasma sintering

• Novel ‘Flash Spark Plasma Sintering’ technique was applied to melt-spun Nd–Fe–B.
• Extremely rapid deformation (<3.6 s−1) and heating (2660 K min−1) observed.
• Anisotropic, nanostructured, high coercivity (1600 kA m−1) material produced.
• ‘FSPS’ is a promising technique for efficient production of anisotropic Nd–Fe–B.

A Spark Plasma Sintering (SPS) furnace was used to Flash-Sinter (FS) Nd–Fe–Dy–Co–B–Ga melt spun permanent magnetic material. During the 10 s “Flash” process (heating rate 2660 K min−1), sample sintering (to theoretical density) and deformation (54% height reduction) occurred. This produced texturing and significant magnetic anisotropy, comparable to conventional die-upset magnets; yet with much greater coercivities (>1600 kA m−1) due to the nanoscale characteristics of the plate-like sintered grains. These preliminary results suggest that Flash-SPS could provide a new processing route for the mass production of highly anisotropic, nanocrystalline magnetic materials with high coercivity.

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