Study of the oxidation and reduction kinetics of copper iron oxide [CuFeO2] in the Cu-Fe-O system

The effect of surrounding atmosphere on the phase relations of CuFeO2 during crystal growth was investigated under CO2, Ar, Ar + 0.5% O2, Ar + 1% O2, and Ar + 2% O2, respectively, using scanning electron microscopy (SEM) together with electron probe microanalysis (EPMA) and X-ray powder diffraction (XPD). CuFeO2 was found to have partially decomposed into Cu2O and Fe2O3 before melting, and crystal growth was progressed by means of the traveling-Cu2O solvent. Under CO2 and Ar, Cu2O was found to be reduced to Cu. No reduction of Cu could be found under Ar + 0.5% O2, Ar + 1% O2, and Ar + 2% O2 atmospheres, whereas the reduction of CuO was observed Under an Ar + 2% O2 atmosphere.