Effect of Zr Addition on Magnetic Properties of TbCu7-type Sm-Fe-N Powder Synthesized by Low-temperature Ca Reduction Diffusion Process

• Published in: IEEE transactions on magnetics Vol. 59; no. 11; p. 1
• Main Authors: Sato, Suguru, Suzuki, Kazuyuki, Okada, Shusuke
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Chemical reduction; High temperature; Iron; Low temperature; Magnetic properties; Magnetism; Metallurgy; Metals; Microstructural analysis; Permanent magnets; Perpendicular magnetic anisotropy; Phase ratio; Powders; Reduction; Samarium; Samarium compounds; Saturation magnetization; Temperature; X-ray scattering; Zirconium
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2023.3279354

The effect of the addition of Zr on magnetic properties of anisotropic TbCu 7 -type Sm-Fe-N powders prepared by the low-temperature reduction diffusion process was investigated. At the reduction diffusion temperature of 873 K, the TbCu 7 -type Sm-Fe phase ratio decreased with an increase in the Zr content. At a higher reduction diffusion temperature of 973 K, a TbCu 7 -type Sm-Fe phase was obtained regardless of the amount of Zr added. Furthermore, the Th 2 Zn 17 -type Sm-Fe phase was obtained without the addition of Zr. Therefore, it was indicated that the addition of Zr can stabilizes the TbCu 7 -type Sm-Fe phase at high temperatures. By nitriding the obtained powder, a TbCu 7 -type Sm-Fe-N powder was obtained; however its magnetic properties deteriorated as the amount of Zr increased. Microstructural analysis revealed that the element ratio Zr/Sm in the TbCu 7 -type Sm-Fe-N particles saturated at approximately 0.05, and the excess Zr was consumed to form the ZrFe 2 phase on the outside of the particles. It was concluded that the ZrFe 2 phase results in the deterioration in the magnetic properties of the powder.