Chemical synthesis of Nd 2 Fe 14 B/Fe-Co nanocomposite with high magnetic energy product

• Published in: RSC advances Vol. 11; no. 51; pp. 32376 - 32382
• Main Authors: Ngo, Hieu Minh, Lee, Gyutae, Haider, Syed Kamran, Pal, Umapada, Hawari, Thomi, Kim, Kyung Min, Kim, Jongryoul, Kwon, Hae-Woong, Kang, Young Soo
• Format: Journal Article
• Language: English
• Published: England 27.09.2021
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/D1RA03760A

Nd Fe B is one of the most popular permanent magnets (PMs) possessing the best energy product (BH) among the common PM materials. However, exchange-coupled nanocomposite magnets fabricated by embedding nanostructures of soft-phase magnetic materials into a hard-phase magnetic matrix manifest higher remanence and a higher energy product. Here we present the fabrication of exchange coupled Nd Fe B/Fe-Co magnetic nanocomposites using gel-combustion and diffusion-reduction processes. Pre-fabricated CoFe O nanoparticles (NPs) of ∼5 nm diameter were incorporated into a Nd-Fe-B oxide matrix during its synthesis by gel-combustion. The obtained mixed oxide was further processed with oxidative annealing at 800 °C for 2 h and reductive annealing at 900 °C for 2 h to form a Nd Fe B/Fe-Co nanocomposite. Nanocomposites with different mol% of soft-phase were prepared and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and physical property measurement system (PPMS) to study their crystalline phase, morphology and magnetic behavior. Addition of 7.7 mol% of soft-phase was found to be optimum, producing a coercivity ( ) of 5.6 kOe and remanence ( ) of 54 emu g in the nanocomposite.