Neodymium iron boron magnetic material and preparation method thereof

The invention provides a neodymium iron boron magnetic material and a preparation method thereof, belonging to the technical field of a permanent magnet material. The preparation method comprises the following steps of: coarsely breaking a spindle block or a fast-hardening sheet, and grinding into powder by means of air current; shaping by means of orienting and pressing under the magnetic field; performing the cold isostatic pressing and the high-vacuum sintering to a blank body; and tempering to prepare the neodymium iron boron magnetic material so as to obtain a neodymium iron boron magnet, wherein the content of oxygen is in the range of 1500-4400ppm, and the squareness achieves 98-99%. By observing the microscopic structure of the magnet, the result shows that: the content of the abundant Nd phase oxygen of the dhcp structure in the magnet is less than 9at.%, and the content of the abundant Nd phase oxygen of the fcc structure is 10at.%-48at.%.