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

Taichi Abe; Masao Morishita; Ying Chen; Arkapol Saengdeejing; Kiyoshi Hashimoto; Yoshinao Kobayashi; Ikuo Ohnuma; Toshiyuki Koyama; Satoshi Hirosawa

doi:10.1080/14686996.2021.1936627

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

Sci Technol Adv Mater. 2021 Jun 4;22(1):557-570. doi: 10.1080/14686996.2021.1936627. eCollection 2021.

Authors

Taichi Abe¹, Masao Morishita², Ying Chen³, Arkapol Saengdeejing³, Kiyoshi Hashimoto¹, Yoshinao Kobayashi⁴, Ikuo Ohnuma¹, Toshiyuki Koyama⁵, Satoshi Hirosawa¹

Affiliations

¹ Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, Japan.
² Department of Chemical Engineering and Materials Science, University of Hyogo, Hyogo, Japan.
³ School of Engineering, Tohoku University, Sendai, Japan.
⁴ Department of Material Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan.
⁵ Department of Materials Design Innovation Engineering, Nagoya Univ., Nagoya, Japan.

Abstract

For the Nd-Fe-B permanent magnets, a prototype thermodynamic database of the 8-element system (Nd, Fe, B, Al, Co, Cu, Dy, Ga) was constructed based on literature data and assessed parameters in the present work. The magnetic excess Gibbs energy of the Nd₂Fe₁₄B compound was reassessed using thoroughly measured heat capacity data. The Dy-Nd binary system was reassessed based on formation energies estimated from ab initio calculations. The constructed database was applied successfully for estimations of phase equilibria during the grain boundary diffusion processes (GBDP) and the reactions in the hydrogenation decomposition desorption recombination (HDDR) processes.

Keywords: 203 Magnetics / Spintronics / Superconductors; 40 Optical, magnetic and electronic device materials; 407 CALPHAD / Phase field methods; 605 Databases, data structure, ontology; Gibbs energy; Thermodynamic database; metastable states; phase equilibria.

Publication types

Review

Grants and funding

This work is supported by the Elements Strategy Initiative Center for Magnetic Materials (ESICMM) under the outsourcing project of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT).