TG/DSC analysis of Fe{sub 8}(OOH){sub 16}Cl{sub 1.3} nanospindles

The thermal analysis of Fe{sub 8}(OOH){sub 16}Cl{sub 1.3} (Akaganeite-M) nanospindles prepared by the hydrolysis of FeCl{sub 3} 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 Fe{sub 8}(OOH){sub 16}Cl{sub 1.3} nanospindles are calcined at different temperatures for 30 min in N{sub 2} atmosphere: Fe{sub 1.833}(OH){sub 0.5}O{sub 2.5} and magnetite obtained at 250 deg. C; pure magnetite (Fe{sub 3}O{sub 4}) obtained at 630 deg. C; and magnetite containing some iron nitrides (Fe{sub 2}N and Fe{sub 4}N) obtained at 800 deg. C. The calcination of Fe{sub 8}(OOH){sub 16}Cl{sub 1.3} provides a new method to prepare pure magnetite.