The comparative performance of Nd(Fe, Co)B magnets formed by rapid quenching and by sintering

Abstract

The structures and magnetic properties of crystalline Nd(Fe, Co)B alloys have been studied by X-ray diffraction, differential thermal analysis, transmission electron microscopy and vibrating sample magnetometry. It was observed that the dependences of the magnetization and the Curie temperature of crystallization on the concentration of cobalt are similar to those of other crystal alloys. On transforming the amorphous alloy to the crystalline alloy, a b.c.c. phase, similar to α-Fe, is formed first and then tetragonal Nd₂(Fe, Co)₁₄B is formed at about 600°C. The mechanism of coercivity of Nd(Fe, Co)B magnets formed by quenching and sintering is also discussed.