Development of a prototype thermodynamic database for Nd-Fe-B permanent magnets

Area of Science:

• Materials Science
• Thermodynamics
• Computational Materials Science

Background:

• Neodymium-iron-boron (Nd-Fe-B) magnets are critical for modern technologies.
• Accurate thermodynamic data is essential for optimizing their performance and manufacturing.

Purpose of the Study:

• To construct a prototype thermodynamic database for an 8-element system relevant to Nd-Fe-B magnets.
• To improve the accuracy of thermodynamic calculations for key magnetic compounds and binary systems.

Main Methods:

• Compiled literature data and assessed parameters to build the thermodynamic database.
• Reassessed the magnetic excess Gibbs energy of Nd2Fe14B using heat capacity data.
• Utilized ab initio calculations to estimate formation energies for reassessing the Dy-Nd binary system.

Main Results:

• Successfully constructed a prototype thermodynamic database for the 8-element system (Nd, Fe, B, Al, Co, Cu, Dy, Ga).
• Improved accuracy in modeling the magnetic properties of Nd2Fe14B and the Dy-Nd binary system.
• Validated the database by accurately estimating phase equilibria in grain boundary diffusion processes (GBDP) and hydrogenation decomposition desorption recombination (HDDR) processes.

Conclusions:

• The developed thermodynamic database provides a reliable tool for predicting phase equilibria in Nd-Fe-B magnet processing.
• This work facilitates the optimization of manufacturing processes like GBDP and HDDR for enhanced magnet performance.
• The methodology sets a precedent for creating advanced thermodynamic databases for functional materials.