Redox synthesis of magnetite powder from metallic iron and FeO(OH) under mixing-grinding with the assistance of H2O2 as an oxidizing reagent has been proposed. Deformability of the metal–oxide system induces the kneading of am-FeO(OH)... more
Redox synthesis of magnetite powder from metallic iron and FeO(OH) under mixing-grinding with the assistance of H2O2 as an oxidizing reagent has been proposed. Deformability of the metal–oxide system induces the kneading of am-FeO(OH) into metallic iron to activate, while the iron is oxidized to Fe(OH)2 and/or FeO by H2O2 contained in the grinding liquid (acetone). Only the reaction product, γ-Fe3O4, is obtained. The adhesivity of the powder system due to iron reduces with the progress in synthesis reaction forming non-deformable magnetite powder to result in its dispersion into acetone. The primary particle size of the γ-Fe3O4 powders formed is less than 100 nm. The saturation magnetization of the synthesized γ-Fe3O4 is 9.24×10−5 Wb m g−1, which is about 90% of the commercially available fine γ-Fe3O4 powders with needle-like shapes.
Conducting polymer-based magnetic composites with controlled magnetic behaviour have been synthesized by chemical polymerization in nanoparticle containing organic media. Poly(3-thiophene-acetic-acid)–Fe3O4 hybrids have been prepared with... more
Conducting polymer-based magnetic composites with controlled magnetic behaviour have been synthesized by chemical polymerization in nanoparticle containing organic media. Poly(3-thiophene-acetic-acid)–Fe3O4 hybrids have been prepared with five different iron-oxide contents, up to 20 m/m%, according to the results obtained by thermogravimetric analysis (TGA) and inductively coupled plasma atomic emission spectroscopic (ICP-AES) measurements. X-ray diffraction (XRD) and Mössbauer spectroscopic results gave direct evidences for the incorporation of both maghemite and magnetite. Photoacoustic Fourier transform infrared spectroscopic (PAS-FT-IR) measurements showed a chemical interaction between the polymer and the iron-oxide particles. SQUID investigations indicated a typical superparamagnetic behaviour for all samples, where saturation magnetization values proved to be tunable by the Fe3O4 content. After coating them onto electrode surfaces, basic electrochemical activity of the composite samples was demonstrated by cyclic voltammetry.
