Abstract
Nd10-xDyxFe85B5 (x = 0-3) alloy samples were melted and then solidified in the containerless state of a drop tube at oxygen partial pressure of 10-1Pa. The calculated cooling rate of the spherical sample was over 103K/s. The Nd10Fe85B5 sample consists of the Nd2Fe17Bx metastable phase together with the α-Fe dendrite. The metastable phase was partially decomposed into small grains of Nd2Fe14B and α-Fe phases by a solid state decomposition reaction. The substitution of Dy for Nd in the range from 10 to 20 atomic percent was effective to suppress the primary formation of the α-Fe dendrite and to promote the formation of the RE2Fe17Bx metastable phase. When the substitution rate of Dy increased to 30 atomic percent, a large amount of the α-Fe dendrite was formed because an oxide layer of rare earth elements was generated at the sample surface due to the easy oxidization tendency of Dy.
