Nanostructuring silica-iron core-shell particles in a one-step aerosol process.

Silica-coated iron (Fe@SiO 2 ) particles have attracted considerable interest as a potential powder core material due to their distinctive advantages, including higher magnetic saturation and enhanced electrical resistance. In this study, the submicron-sized core-shell Fe@SiO 2 particles were successfully synthesized in a single step via an aerosol process using a spray pyrolysis method assisted by a swirler connector for the first time. Changing the reducing agent concentration (supplied H 2 ) and tuning the number of core (Fe) particles were investigated to achieve the desired Fe@SiO 2 particles. The results indicated that an excessive number of cores led to the appearance of FeO crystals due to insufficient reduction. Conversely, an insufficient number of cores resulted in a thicker SiO 2 shell, which hindered the penetration of the supplied H 2 gas. Furthermore, the produced Fe@SiO 2 particles exhibited soft-ferromagnetic characteristics with an excellent magnetic saturation value of 2.04 T, which is close to the standard theoretical value of 2.15 T. This work contributes new insights into the production of core-shell Fe@SiO 2 particles, expanding their applicability to advanced soft-magnetic materials.