A CONTRIBUTION TO THE KNOWLEDGE OF PHASE-EQUILIBRIA AND THE MAGNETIC-PROPERTIES OF THE ND-FE-B-X SYSTEMS (X=AL,CO,V)

A technique based on diffusion couples for the determination of the co mpositions of different phases present in the Fe-Nd-B and Fe-Nd-B-Al s ystems was used. By this technique the composition of the liquid in eq uilibrium with the solid phases could be determined. Since all element s are encapsulated in an iron capsule, the study of oxidation-sensitiv e elements like neodymium was easily made. By using this technique, ne w information on the composition of the liquid phase in equilibrium wi th solid phases in the Fe-Nd-B system as well as the Fe-Nd-B-Al system was determined at two temperatures. This information was used to impr ove the representation of the liquidus surfaces of the systems. The ef fects of Al, V, and/or Co additions on the coercivity and energy produ ct of sintered Fe-Nd-B magnets are also presented.