| Title |
The Effect of Formation of fine dispersoids on Enhanced Coercivity of Fe - Nd - B Magnet Prepared by Rapid Solidification Technology |
| Authors |
양충환(C . J . Yang); 최승덕(S . D . Choi) |
| Abstract |
The effect of HfB₂ and ZrB₂ dispersoids on magnetic properties and microstructure of Fe-Nd-B magnetic powders as well as magnet has been investigated. Amorphous rapidly solidified powders of Fe-Nd-B alloys with 1 to 3 wt.% HfB₂(or ZnB₂) were prepared by the melt spinning process. Powders were consolidated by hot extrusion into fully densified magnet bars. The fine dispersoids of HfB₂(or ZrB₂) were formed while crystallizing of the amorphous material during hot extrusion process. The coercivity of Fe-Nd-B magnet increased as the dispersoids were formed. The microstructure of the extruded magnet indicated that the enhancement of coercivity was caused by grain refinement due to formation of fine HfB₂(or ZrB₂) dispersoids. In general, the addition of HfB₂(or ZrB₂) in crystallized powder were accompanied with the decrease in the remnant magnetization. Curie temperature of the Fe-Nd-B alloy was independent of the amount of HfB₂ in the composition range investigated. |