CORE-SHELL-CORE NANOPARTICLE SYSTEM, CORE-SHELL-CORE FeCo/SiO2/MnBi NANOPARTICLE SYSTEM PREPARATION METHOD, AND CORE-SHELL-CORE NANO-AGGREGATE OF FeCo/SiO2 NANOPARTICLE WITH MnBi NANOPARTICLE

摘要

PROBLEM TO BE SOLVED: To provide a hard magnetic powder having high coercivity.SOLUTION: Core-shell-core nanoparticles of an iron-cobalt alloy core, a silica shell and a manganese bismuth alloy core or nanoparticle on the surface of the silica shell (FeCo/SiO/MnBi) are provided. The core-shell-core nanoparticles are alternative materials to rare-earth permanent magnets because of the hard magnetic manganese bismuth in nanometer proximity to the soft magnetic iron cobalt.