Preparation and characterization of microsized FeCO3, Fe3O4 and Fe2O3 with ellipsoidal morphology

Ellipsoidal FeCO3 microcrystals with length of ∼5–6.5 μm and width of ∼2.5–3.5 μm have been synthesized by an ascorbic acid assisted hydrothermal process. Both microsized ellipsoidal Fe2O3 and Fe3O4 microparticles were obtained using the spindle FeCO3 as sacrificial templates via direct thermal decomposition and sealed thermal decomposition for 2 h at 500 °C, respectively. The products were characterized with the X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and superconducting quantum interference device magnetometer. The influences of the experimental factors on growth of the FeCO3 micron crystals were also investigated.