速凝铸造工艺制造高性能烧结Nd-Fe-B磁体

Sintered Nd-Fe-B Magnet Produced by the Strip Casting Technology

研究了用速凝铸造工艺制造高性能烧结Nd Fe B磁体·同传统的铸锭工艺相比,速凝铸造工艺细化柱状晶,阻止α Fe枝晶相的产生,改善了铸态合金的微观结构·柱状晶宽度基本在5～25μm之间,尺寸较均匀;在制粉过程中容易得到粒度分布较好的磁粉;富Nd相分布较好,所以在较低烧结温度下可得到较高密度的磁体;由于具有细小均匀的微结构,利用速凝铸带工艺烧结出的磁体具有更高的Br,Hci和(BH)max·

High performance NdFeB magnet produced by the strip casting (SC) was investigated. Compared with traditional ingot casting technology, the SC processing refines and homogenizes the columnar structures and suppresses the formation of αFe dendrites so that greatly improves the microstructure in the ascasted alloy. It was found that the Ndrich phase distributes uniformly along the grain boundaries of fine columnar matrix phase in the speed cooled strip. The columnar grains are about 5～25?μm in mean width. Using the cast strips for powder production, the fine powder with a good particle size distribution can be obtained easily. Due to the optimum distribution of Ndrich phase, the magnets made from the cast strip shows high density even at a lower sintering temperature. The magnets made by SC technology showed a higher Br,Hci and (BH)max than that made by traditional ingot technology.