High-stability sintered neodymium-iron-boron magnet and preparation method thereof

The invention discloses a high-stability sintered neodymium-iron-boron magnet and a preparation method thereof. The preparation method of the magnet comprises the steps of alloy smelting, crystallization treatment, crushing powder preparation, powder modification, powder mixing, magnet preparation and the like. Firstly, an alloy I with the component being (DyNd) (CoFe) B and an alloy II with the component being (DyNd) TbFe (CuAlGa) are smelted, then the alloy II rich in Tb is mixed into the alloy I without Tb, and Tb is controlled in grain boundary rare earth-rich phase and RE2Fe14B phase grain surface layers in a final magnet. The strengthening effect of the Tb element on the grain boundary rare earth-rich phase and RE2Fe14B phase grain surface layers is exerted, the coercive force of the magnet is improved, and the coercive force temperature coefficient of the magnet is improved. The obtained product has the characteristics of high magnetic field stability and high coer