TG/DSC analysis of Fe8(OOH)16Cl1.3 nanospindles

The thermal analysis of Fe8(OOH)16Cl1.3 (Akaganeite-M) nanospindles prepared by the hydrolysis of FeCl3 solutions are determined by thermogravimetric analyses and differential scanning calorimetry (TG/DSC), in conjunction with field-emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD). Different products are formed after Fe8(OOH)16Cl1.3 nanospindles are calcined at different temperatures for 30 min in N2 atmosphere: Fe1.833(OH)0.5O2.5 and magnetite obtained at 250 °C; pure magnetite (Fe3O4) obtained at 630 °C; and magnetite containing some iron nitrides (Fe2N and Fe4N) obtained at 800 °C. The calcination of Fe8(OOH)16Cl1.3 provides a new method to prepare pure magnetite.