We have investigated two solid-state phase transformations-nitriding of the ternary alloy FeCuB ribbons and martensitic phase transformation in the FeCuBN ribbons using x-ray diffraction, Auger Electron spectroscopy, and scanning electron microscopy. We also studied the diffusion kinetics of nitrogen in FeCuB ribbons and found the activation energy of N to diffuse in the FeCuB matrix and the diffusion coefficient of N at different temperatures. We investigated the evolution of the microstructure during nitriding process and found a layered growth of iron nitride in the FeCuB matrix. Finally, the martensitic phase transformation of the FeCuBN ribbons was also optimized, and the optimizing parameters for the martensitic phase transformation of FeCuB ribbons were reported.
Bibliographical noteFunding Information:
This work was supported in part by ARPA-E BCT Fe 16 N 2 Magnet project under contract No. 0472-1595 . Parts of this work were carried out in using the Characterization Facility, which receives partial support from NSF through the NSF Minnesota MRSEC program under Award Number DMR-0819885 . We are grateful to Dr. Yiming Wu of Niron Magnetics Inc. for wonderful help in melt spinner and Nitriding furnace setup and insightful discussion. Md Mehedi is grateful to Jinming Liu for repeated discussions on improving the nitriding process, Dr. Xiaowei Zhang for their insightful discussion on α″-Fe 16 N 2 crystal structure and magnetic properties, Dr. Guannan Guo for an insightful discussion on the kinetics, and Dr. Fan Zhang for her suggestion during one of the SEM images collection. Dr. Jian-Ping Wang has equity and royalty interests in and serves on the Board of Directors and the Scientific Advisory Board, for Niron Magnetics Inc, a company involved in the commercialization of FeN magnet. The University of Minnesota also has equity and royalty interests in Niron Magnetics Inc. These interests have been reviewed and managed by the University of Minnesota in accordance with its Conflict of Interest policies.
This work was supported in part by ARPA-E BCT Fe
© 2019 Acta Materialia Inc.
- Hard magnets
- Iron nitride
- Permanent magnets
- Phase transformation
- Rare-earth-free magnet