Formation of magnetic fexoy/silica core-shell particles in a one-step flame aerosol process

Bing Guo, Hoon Yim, Airat Khasanov, John Stevens

Research output: Contribution to journalArticle

14 Citations (Scopus)


In this study, iron silicon oxide particles were generated in a one-step flame assisted spray pyrolysis (FASP) process using H2/air or H2/O2 diffusion flames. A colloidal precursor solution was used, which contained dissolved iron nitrate and stably suspended silica nanoparticles. H2/air flames resulted in magnetic fexOy/silica core-shell particles. There was a correlation between particle size and particle structure; particles larger than 500 nm had the core-shell structure, but smaller particles had non-core-shell structures. H2/O2 flames only resulted in nanoparticles that had non-core-shell structures. The core-shell particles had a iron oxide core that was hermetically enclosed in a uniform silica shell with a typical thickness of approximately 100 nm; they were superparamagnetic with a room-temperature saturation magnetization greater than 24 emu/g. Temperature history of the particles may be used to explain the correlation between flame type and particle structure. The correlation between particle size and structure may be due to size-dependent thermodynamic stability of the structures, or kinetics of heat and mass transfer. The results from this study suggest that micrometer sized iron oxide silica core-shell magnetic particles could be generated from a one-step flame aerosol process, but FexOy/silica nanoparticles (<100 nm) with the core-shell structure cannot be generated in a one-step flame aerosol process.

Original languageEnglish
Pages (from-to)281-291
Number of pages11
JournalAerosol Science and Technology
Issue number4
Publication statusPublished - 1 Apr 2010


ASJC Scopus subject areas

  • Environmental Chemistry
  • Materials Science(all)
  • Pollution

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