Infrared spectra of the oxidation products of submicronic synthetic titanomagnetites

Abstract

The oxidation of submicronic synthetic titanomagnetites (Fe 2−2x 3+Fe 1+x 2+Ti x 4+) O 4 2− with O< x < 0.82 was investigated using IR spectrometry in the temperature range 350–750°C. At 350°C, these compounds are oxidized in cation deficient spinels which show a large number of absorption bands over the range 200–800 cm −1 suggesting an ordered distribution of cations and vacancies on octahedral sites. At 750°C, we observe structural change and the spectrum exhibits for x ≧ 0.40 bands of αFe 2O 3 and pseudobrookite Fe 2TiO 5. In the temperature range 550–700°C, an intermediate phase of spinel structure rich in titanium has been identified with the help of IR spectrometry and diffraction RX.