PREPARATION METHOD OF IMPROVED SINTERED NEODYMIUM-IRON-BORON (ND-FE-B) CASTING STRIP

The present disclosure belongs to the technical field of preparation of rare earth permanent magnetic materials, and in particular, relates to a preparation method of improved sintered neodymium-iron-boron (Nd-Fe-B) casting strips. The preparation method includes the following steps: firstly nucleation assisted alloy particles used for sintered Nd-Fe-B casting strips are prepared, all elements are weighted as follows: 26.68-28% of Pr-Nd, 70-72.5% of Fe and 0.90-1% of B, and a Pr element in two elements of Pr-Nd accounts for 0-30wt%; the compounded materials are smelted and poured through a conventional technology to obtain alloy strips, then the alloy strips are crushed into particles with diameter of 1-10mm by a mechanical crushing method, to be used as nucleation assisted alloy particles used for the sintered Nd-Fe-B casting strips; secondly, Nd-Fe-B casting strips are prepared: the prepared intermediate materials are smelted and melted into molten steel according to a conventional sintered Nd-Fe-B smelting technology, and then are refined; after the intermediate materials are fully melted, the nucleation assisted alloy particles are added according to the weight percent of 3-6 wt%; and after the nucleation assisted alloy particles are added, smelting is performed for 3-15 minutes under the condition that power is reduced by 150-250 KW, pouring is performed, and final Nd-Fe-B alloy casting strips are obtained. The metallographic phase quality of the Nd-Fe-B casting strips prepared by the technology and the technique is obviously improved, and the intrinsic coercivity Hcj of magnet finished products prepared by the casting strips is obviously improved.