P. Camargo, G. G. Nunes, G. Friedermann
Dec 10, 2003
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Influential Citations
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Journal
Materials Research Bulletin
Abstract
Abstract The first structurally characterised titanium and iron isopropoxide, [FeCl{Ti 2 (OPr i ) 9 }] ( 1 ), has been used as a single-source precursor for TiO 2 /Fe 2 TiO 5 composites prepared by the sol–gel route. Two distinct hydrolysis and condensation conditions were employed, followed by drying and thermal treatment up to 1000 °C. Product composition and oxide phase transitions were characterised by powder X-ray diffractometry and Raman, electron paramagnetic resonance, Mossbauer and Fourier-transformed infrared spectroscopies. A mixture of nanometric-size TiO 2 (anatase, 3.6–5.8 nm) and amorphous iron(III) oxide was obtained up to 500 °C, while TiO 2 (rutile), α-Fe 2 O 3 (hematite) and Fe 2 TiO 5 (pseudobrookite) were found at 700 °C. At 1000 °C, only rutile and pseudobrookite were observed. These results suggest that 1 behaves as a type III single-source precursor. Powders calcined at 1000 °C were analysed for surface morphology, microstructure and elemental composition by scanning electron microscopy/energy dispersive X-ray spectroscopy. Results suggest no phase segregation on a sub-micrometer level. Different morphologies were observed for the materials produced by the N 2 route, and this could relate to early crystal growth in an oxygen-deficient environment.