METHOD FOR PREPARING HIGH-PERFORMANCE DOUBLE-MAIN PHASE SINTERED MISCH-METAL IRON BORON MAGNET BY TWO-STEP DIFFUSION METHOD

摘要

A method for preparing a high-performance double-main phase sintered misch-metal iron boron magnet by a two-step diffusion method, relating to the technical field of rare earth magnetic material preparation. The components of the two main phase alloys are respectively RE-Fe-B (RE is Nd or Pr) and (Nd, MM)-Fe-B, wherein MM is misch-metal. First, with a PrHoFe alloy rapidly quenched sheet serving as a diffusion source, the surface of a (Nd, MM)-Fe-B hydrogen decrepitated powder particle is uniformly coated with a PrHo-rich compound layer, and the coercivity is improved by utilizing high anisotropic fields of Pr2Fe14B and Ho2Fe14B; then, with a ZrCu alloy rapidly quenched sheet serving as a diffusion source, the surface of the powder particle having experienced the first-step diffusion is uniformly coated with a Zr-rich layer to prevent growth of MM-containing main phase crystal grains and inhibit mutual diffusion with the other main phase in the two main phases in the sintering process, thereby obtaining high coercivity.