Rapidly-Solidified Permanent Magnet Materials: Factors Affecting Quenchability211 and Magnetic Properties in Nd2Fe14B

摘要

Insight into the solidification behavior of Nd(sub 2)Fe(sub 14)B-based materials211u001eprocessed by rapid solidification techniques has been obtained by a systematic 211u001eexperimental study of the Curie temperatures of selected phases found in these 211u001ematerials. Nd(sub 2)Fe(sub 14)B-based materials fabricated by two disparate rapid 211u001esolidification techniques, inert gas atomization (IGA) and melt-spinning, has 211u001ebeen studied. The compositions of the starting materials have been altered with 211u001eadditions of the refractory elements Ti and C which are known to alter the 211u001esolidification behavior of these materials. Special emphasis has been placed on 211u001etrying to understand the effect of alloying additions upon the nature of the 211u001equenched glass, the distribution of the elemental additions within the Nd(sub 211u001e2)Fe(sub 14)B lattice and the evolution of the elemental partitioning with quench 211u001erate and annealing condition. The experimental Curie temperature data obtained 211u001eusing thermal analysis methods from the particles produced by gas-atomization is 211u001econsistent with both an ejection of quenched-in refractory species from the 211u001ecrystalline Nd(sub 2)Fe(sub 14)B lattice and with increased crystallographic 211u001eorder as particle size, and hence grain size, increases. Magnetic ac 211u001esusceptibility measurements performed on nominally-amorphous Nd(sub 2)Fe(sub 14)B 211u001eribbons produced by melt-spinning indicate a decrease of the Curie temperature 211u001ewith increasing quench rate, a result that may be attributed either to the degree 211u001eof Ti/C retention in the glass or to the degree of disorder in the glass, 211u001eindependent of Ti/C retention.