The microstructure of a Nd12.73Fe80.99B5.78Zr0.50 magnet was determine
d by transmission electron microscopy before and after disproportionat
ion by a solid-HDDR process. Zr eliminates free iron dendrites and res
ults in platelet-like ZrB2 precipitates in the intergranular region, i
nhibiting grain growth. The ZrB2 platelets are not affected by the dis
proportionation. The role of Zr on the memorizing effect was studied.