Abstract: A neodymium-iron-boron magnet is provided. The neodymium-iron-boron magnet is subject to diffusion and permeation of a heavy rare earth element, the neodymium-iron-boron magnet includes a heavy-rare-earth diffusion region at a surface layer and a core non-diffusion region, and the neodymium-iron-boron magnet has the heavy-rare-earth diffusion region at regions, which have normal directions consistent with three axes of a three-dimensional Cartesian coordinate system, of the surface layer. The present application extends the principle of diffusion from microscopic grains to macroscopic magnets. Diffusion layers of different depths may be obtained by adjusting temperature and time of heat treatment. Through the magnetic hardening of the surface layer of the magnet, the coercive force of the magnet is increased, and the magnet remanence (Br) and the maximum magnetic energy level (BHmax) are very slightly reduced. The producing process is simple, and highly controllable.

Abstract: The present disclosure provides neodymium-iron-boron magnetic body having gradient distribution, comprising an ease-to-demagnetize zone and a hard-to-demagnetize zone, wherein in a direction perpendicular to magnetization direction, remanence of the ease-to-demagnetize zone is less than remanence of the hard-to-demagnetize zone, and coercivity of the ease-to-demagnetize zone is greater than coercivity of the hard-to-demagnetize zone; and along the direction perpendicular to magnetization direction, the remanence and the coercivity of the ease-to-demagnetize zone are respectively a constant value, and the remanence and the coercivity of the hard-to-demagnetize zone are respectively a constant value. Due to the gradient distribution of remanence and coercivity of the neodymium-iron-boron magnetic body provided by the present application, the remanence, coercivity, magnetic flux and surface magnetic field of the neodymium-iron-boron magnetic body are optimized.