The invention relates to the technical field of permanent
magnet preparation, and particularly discloses a high-temperature-resistant
neodymium-iron-
boron magnet and a preparation method thereof. The high-temperature-resistant
neodymium-iron-
boron magnet comprises the following elements in percentage by
mass: 17.4%-19.5% of Nd, 0.66%-0.72% of B, 38.37%-41.19% of Fe, 0.36%-4.8% of Dy, 0.18%-0.3% of Nb, 0.18%-0.3% of Al, 0.03%-0.09% of Cu, 29.1%-34.8% of an
alloy rapid hardening sheet and the balance of unremovable impurities, wherein the
alloy rapid hardening sheet contains Pr, Tb, Bi and Sn; the preparation method comprises the following steps:
grinding the surface of an
alloy rapid hardening sheet to be bright, mixing the alloy rapid hardening sheet with a pretreated magnet block, adding
zirconium oxide balls, putting into a reaction kettle of a rotary
diffusion furnace, vacuumizing the reaction kettle, introducing
argon, rotating at the rotating speed of 4-6r / min, keeping the temperature at 700-704 DEG C for 3-7h, and carrying out rotary
diffusion, so as to obtain the
zirconium oxide-based
composite material. And then carrying out heat preservation at 850-950 DEG C for 2-4 hours for high-temperature
diffusion and heat preservation at 450-550 DEG C for 2-4 hours for
tempering heat treatment by using a
vacuum tube furnace in a vacuum environment. The high-temperature-resistant
neodymium-iron-
boron magnet has the
advantage that the defect that
heat resistance of a conventional neodymium-iron-boron magnet is still insufficient is overcome.