Solution Combustion Synthesis and Characterization of Magnetite, Fe 3 O 4 , Nanopowders

Combustion synthesis of Fe 3 O 4 and properties of the resulted powders have been discussed in relation to reaction atmosphere (in air/in the absence of air) and used fuel (sucrose, citric acid and glucose). Conducting the combustion reactions in air caused the rapid oxidation of Fe 2+ to Fe 3+ under the influence of the atmospheric oxygen; therefore the final reaction product was a mixture of α‐ Fe 2 O 3 and γ‐ Fe 2 O 3 . In order to avoid the oxidation of Fe 2+ to Fe 3+ a simple but efficient solution has been suggested: combustion reactions were carried out in a round bottom flask and the evolving gases were bubbled in a beaker filled with water. This solution allowed the preparation of Fe 3 O 4 nanopowders, with crystallite size varying from 10 nm (glucose) to 18 nm (citric acid). Depending on the used fuel, the specific surface area of the magnetite powders varied between 56 m 2 /g (citric acid) and 106 m 2 /g (glucose). The saturation magnetization of Fe 3 O 4 powders prepared in the absence of air ranged between 55.3 emu/g (glucose) and 59.4 emu/g (sucrose).