Microstructure of Nd2Fe17N3 Magnetic Powder Surface with Nano-α-Fe Phases Separated Surface Layer

• Published in: IEEE transactions on magnetics Vol. 59; no. 11; p. 1
• Main Authors: Abe, Satoshi, Akamatsu, Jun, Imaoka, Nobuyoshi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Alpha iron; Heat treatment; Iron; Magnetic anisotropy; Magnetic permeability; Magnetic properties; Magnetism; Microstructural analysis; Microstructure; Nd<sub xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">2 Fe<sub xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">17 N<sub xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">3; Permeability; Phases; Phosphoric acid; Powders; Surface layers; Surface treatment; Transmission electron microscopy; X-ray scattering
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2023.3281897

We investigated the application of Nd 2 Fe 17 N 3 magnetic powder with planar magnetic anisotropy to magnetic field amplification materials at several tens of MHz. Consequently, we succeeded in developing a magnetic property with real permeability ~ 8 and imaginary permeability below 0.8 at 100 MHz using a phosphoric acid coating and a simple heat treatment process in air. In this study, microstructural analysis conducted using transmission electron microscopy and X-ray diffraction revealed that the coating layer became thicker, and the Nd 2 Fe 17 N 3 surface was phase-separated into nano-sized α-Fe phases and Nd-rich phases, either oxide, oxynitride, or nitride. Additionally, the nano-sized α-Fe phases and the nano-sized Nd-rich phases were oriented over a wide area spanning several hundred nanometers. We concluded that these characteristic structures have led to improved properties.