Permanent Magnets

Anisotropic bulk permanent magnets based on Nd-Fe-B alloys are the most widely used types of rare earth magnets, and their fabrication requires precise control of their microstructure. Two approaches to producing such magnets are (i) powder metallurgical sintering and (ii) rapid solidification followed by hot-deformation. In both cases, the resultant phase constitutions and morphology of the microstructure depend on the chemical compositions of the magnets and the processing conditions. Improved knowledge of the underlying thermodynamics and phase equilibria of these systems are important to improving the processing reliability and further development of Nd-Fe-B-based magnets.

Additionally, commercial Nd-Fe-B magnets are not just a simple ternary system, but rather exist as multicomponent alloys where additional elements such La, Ce, and Pr can be adopted to substitute for the more expensive Nd. Other elements may also be added to improve properties such as coercivity.

There is limited handbook data available for these multicomponent alloys, and those that exist do not always take into account variations in chemistry or processing conditions. Where this data is missing, Thermo-Calc can be used to generate the materials property data and make predictions of material behavior throughout the materials life cycle.