Development of SmFe7Nx+.ALPHA.Fe Nanocomposite Magnets.

Abstract

Nano composite magnet material consisting of hard magnetic SmFe7Nx phase and soft magnetic α Fe phase were developed through a process of rapidly quenching method including heat treatment and nitrogenation. Well balanced magnetic performance were obtained for the alloys with the composition of (Sm8Zr3Fe85Co4)N15. The ranges of grain sizes are 20-40nm which are enough small to create exchange coupling interaction between soft and hard magnetic grains. The ratio of α Fe phases with higher magnetization are measured approximately 20% by TEM observation. TEM-EDX study revealed that SmFe7Nx phase have a composition of richer Sm ratio than that of 1-7stoichiometry. Magnetic properties of those powders are as follows: Br=0.97T, HcJ=752kJ/m, (BH)max=140kJ/m3. Bonded magnets have been fabricated with thermoelastic and thermoplastic resins.