The invention discloses a preparation process of a
neodymium-iron-
boron magnet. The preparation process comprises the following steps: a,
smelting: weighing raw materials in proportion, putting
neodymium-iron-
boron powder, Fe3O4,
calcium carbonate powder,
sodium benzoate,
stearic acid and iron into a
smelting furnace, carrying out heating to 1,500 DEG C and 1,600 DEG C, sequentially adding carbonblack,
calcium propionate, SiO2 and
single crystal magnesium oxide, continuing heating until all the raw materials are molten into a
liquid state, adjusting a temperature to 2,750 DEG C and 2,860 DEGC, and keeping the temperature for 3-5 hours to obtain a crude permanent
magnet product solution; b,
powder preparation: cooling and curing the crude permanent
magnet product solution to obtain a
solid crude permanent magnet product, and feeding the
solid crude permanent magnet product into a tube mill for continuous
grinding for 3-5 hours to obtain permanent magnet powder with a particle size of0.5-1 [mu]m; c, pressing: placing the obtained permanent magnet powder in a
magnetic field with a
magnetic field intensity of 20,000-25,000 Gs for orientation and shaping under the action of
argon shielding gas, and then carrying out pressing under a static pressure of 400 MPa to obtain a blank; d,
cutting:
cutting an inclined surface on the blank, and
polishing the inclined surface; and e,
tempering: placing the blank in a vacuum environment with a temperature of 800 DEG C to 900 DEG C for primary
tempering to obtain the permanent magnet.