Micro- and Nanostructures of Fe2O3-SiO2 Sol-Gel Derived Thick Coatings

Thick Fe₂O₃−SiO₂ sol-gel coatings with 30 wt%Fe₂O₃ were prepared on glass substrates under different conditions. These were investigated by scanning electron and atomic force microscopies. The performance of the layers depended also on the way the substrate surface was pretreated. Annealed bulk gel pieces showed phases like FeCl₂×2H₂O and presumably C₉Fe₂O₉ (300°C); at higher annealing temperatures, hematite, cristobalite and magnetite could be found.