The invention discloses a kind of micro-
powder for preparing a
neodymium-iron-
boron permanent
magnet material, a
target type air-current
powder milling method adopted for preparing the micro-
powder and the powder milled from an air-current mill. The
sphericity degree of the micro-powder is greater than or equal to 90%, and the particle
adhesive rate of the micro-powder is less than or equal to 10%. According to the
target type air-current powder milling method, the relation of the
diameter A of a target center, the
diameter B of a side
nozzle and the distance C between the target center and the side
nozzle is A / B=m*(C / A+B), wherein the value range of m is 1-7, and the
jet stream speed of the side
nozzle is 320-580 m / s. The relation of the
diameter F of a grading wheel and the diameter A ofthe target center is F=p*A, wherein the value range of p is 3-6. The air-current milled powder obtained through the method comprises ultrafine powder and the micro-powder, wherein the ratio of the
mass of the ultrafine powder to the total
mass of the air-current milled powder is less than or equal to 0.5%. The micro-powder provided by the invention is uniform in
particle size distribution, narrowin range, low in
nitrogen content and suitable for large-scale production of the high-quality sintered
neodymium-iron-
boron permanent
magnet material. The milled powder obtained through the
target type air-current powder milling method does not contain spit materials. The subsequent process is omitted.