Ferritization of copper ions in the Cu-Fe-O system

Ferrite ceramics were prepared utilizing solid state reactions between CuO and Fe3O4 or alpha-Fe2O3. The samples were analyzed with X-ray diffraction, Fe-57 Mossbauer and FT-IR spectroscopies. For the solid state reaction bet ween CuO and Fe3O4, the initial atomic ratios of Cu:Fe varied between 1:299 and 1:2. With an increase in the amount of CuO in the initial reaction mix ture, there was a corresponding increase in cuprospinel (cubic CuFe2O4) in the final products of the synthesis. For the initial molar ratio of Cu:Fe = 1:2, cuprospinel phase (0.85) and CuFeO2 phase (0.15) were found by XRD, a s the result of solid state reaction between CuO and Fe3O4. In this sample, a small amount of CuO was also detected. For the solid state reaction betw een CuO and alpha-Fe2O3, the initial molar ratio of 1:1 was used. The sampl es prepared at a maximum temperature of 800 degrees C, contained similar fr actions of tetragonal and cubic CuFe2O4 phases, and also minor phases of Cu O and alpha-Fe2O3 as found by XRD. In the samples prepared at between 1000 and 1350 degrees C, the cubic CuFe2O4 phase was found together with small a mounts of CuFeO2 and CuO. Mossbauer spectra showed hyperfine field distribu tions and on the basis of these spectra, calculated parameters, the possibl e presence of Cu+ and Fe2+ ions in the samples was discussed. For the sampl es prepared at 1350 degrees C the FT-IR spectrum suggested a significant in crease in Fe2+ inns, whereas the Mossbauer spectrum and calculated paramete rs were similar to those for the compound Cu0.7Fe2.3O4. (C) 2000 Elsevier S cience S.A. All rights reserved.