The thick bi-layered gel-like film has been grown by anodizing iron in a novel electrolyte composition based on dimethyl sulfoxide and silica hexafluoride acid (H2SiF6) and examined. The thickness of the anodic film composed of the inner orange-colored nanoporous layer and the outer cherry-colored gel-like layer increased at a constant rate up to 40-50 mu m depending on the bath composition and anodizing conditions. Under drying and subsequently annealing, the gel layer shrinks and cracks producing hierarchical morphology of thick films mainly composed of hematite (a-Fe2O3). Scanning electron microscopy, Mossbauer, Raman and energy dispersive X-ray spectroscopies, and X-ray diffraction have been applied to reveal the composition and morphology of these novel films before and following various post-treatments. (C) 2011 Elsevier Ltd. All rights reserved.