Exchange-Coupled SmCo₅/Fe Nanocomposite Magnet Prepared by Low Oxygen Powder Metallurgy Process

In order to realize an anisotropic bulk nanocomposite (NC) magnet, anisotropic SmCo₅ powder and Fe nanopowder were prepared by a low oxygen powder metallurgy process. Single-phase SmCo₅ powder was obtained by an arc melting and jet milling process. Spherical Fe nanopowder with an average particle size of 98 nm was prepared by the low oxygen-induction thermal plasma (LO-ITP) process. Magnetic measurements showed the anisotropic behavior of the SmCo₅ powder and coercivity of 1 MA/m. The sintered SmCo₅/Fe NC magnet displayed the nonlinear spring-back curves, indicating the exchange coupling effect in this NC magnet. Very thin Fe areas were observed between the SmCo₅ grains when non-oxidized Fe nanoparticles were added, and it is assumed that effective exchange coupling was induced in these ideal microstructures. This work proposed the potential of an anisotropic hard magnetic powder prepared by jet milling, and nano-sized soft magnetic particles were prepared by the LO-ITP process for improving the magnetic properties of the anisotropic NC bulk magnet.