Synthesis of the metastable α-Al1.8Fe0.2O3 solid solution from precursors prepared by combustion

Abstract

The aim of the paper is to synthesise α-Al1.8Fe0.2O3 solid solutions from precursors prepared by the nitrate/fuel combustion synthesis route, using either citric acid or urea, or a mixture of both as the fuel, and different fuel/nitrates ratios. In a first part, global reactions are proposed for each synthesis, which are useful to explain the differences in powder volume, morphology, crystallisation state and specific surface area reported in the second part of the study. In a third part, the powders were further calcined at 1100 °C in order to obtain the corundum form. A combination of Mössbauer spectroscopy, XRD and specific surface area measurements revealed that only the powders prepared with Φe = 2 are the desired monophased α-Al1.8Fe0.2O3 solid solutions.