Phase transformations in CaCO3/iron oxide composite induced by thermal treatment and laser irradiation

Abstract

Calcium carbonate (CaCO3)/iron oxide composites were synthesized through a simple one‐step impregnation procedure by mixing iron oxide nanoparticles (γ‐Fe2O3 and Fe3O4) of about 6 nm in size and CaCO3 microparticles (Φ = 2 µm–8 µm, vaterite phase). The morphology and structural properties of CaCO3, iron oxide nanoparticles and CaCO3/iron oxide composites were characterized as a function of low iron content (0 %w to 3.2 %w) by scanning electron microscopy and transmission electron microscopy, X‐ray diffraction and 57Fe Mössbauer spectrometry. The phase transformations induced by thermal treatment and laser irradiation were investigated in situ by X‐ray thermodiffraction (XRTD) and Raman spectroscopy. We have shown that the phase transformations observed by XRTD are also observed under laser irradiation as a consequence of the absorption of the laser irradiation by iron oxide nanoparticles. Copyright © 2012 John Wiley & Sons, Ltd.