Synthesis of AlNiCo core/shell nanopowders

• FeCo–NiAl (core) and Fe3O4 (shell) nanostructures were synthesized.
• Coercivity was increased to 250 Oe.
• The oxide coating acts as a protection layer.

Magnetic core/shell nanostructures have been recently received much interest owing to their utmost potential in permanent magnetic applications. In the present work, AlNiCo permanent magnet powders were synthesized by ball milling and a core/shell nanostructure was obtained using RF induced plasma. The effects of particle size and nanoshell structure on the magnetic properties were investigated in details. The coercivity of AlNiCo powders was found to increase with decreasing particle size, exclusively nanopowders encapsulated with Fe3O4 shell showed the highest coercivity values. The shell structure produced during plasma reaction was found to form a resistant layer against oxidation of metallic nanoparticles.