Preparation and properties of hot-deformed magnets processed from nanocrystalline/amorphous Nd–Fe–B powders

The hot-deformed magnets processed from nanocrystalline/amorphous Nd–Fe–B powders were preparedunderdifferenthot-pressingtemperatures(600–750 °C, at intervals of 25 °C) by the self-made hotpressing equipment. The microstructure and magnetic properties of hot-deformed magnets prepared at different temperatures were also investigated. When the temperature is above 650 °C, the density of magnet reaches 7.5 g·cm~(-3).The optimum magnetic properties of magnetic induction intensity of Br= 1.3 T, optimum energy product of(BH)max= 282.5 kJ·m~(-3),intrinsiccoercivityof Hcj= 1130.0 kA·m~(-1) of hot-deformed magnets are obtained at hot-pressing temperature of 650 °C. X-ray diffractometer pattern shows that the(00 L) texture has been obtained. For the microstructural characteristic, on the one hand, the good magnetic performance is attributed to the fine platelet-like grains with an average length of 410–440 nm at the hot-pressing temperature range from625 to 675 °C. On the other hand, the unaligned coarse grains are observed in all the samples. And the areal fraction of those is gradually increasing with the rise of the hot-pressing temperature, which tends to deteriorate the magnetic properties. The composition map shows the accumulation of Nd/Pr-rich phase in the coarse grains' region.

Preparation and properties of hot-deformed magnets processed from nanocrystalline/amorphous Nd-Fe-B powders

The hot-deformed magnets processed from nanocrystalline/amorphous Nd-Fe-B powders were pre-pared under different hot-pressing temperatures(600-750 ℃,at interval...