Synthesis and thermostructural studies of a CuFe1-xCrxO2 delafossite solid solution with 0<=X<=1

Abstract

In this work, different CuFe1-xCrxO2 compositions with 0<=x<=1 were prepared by a standard solid-state reaction. These oxides crystallize with the delafossite structure. The phase stability and thermal behavior of the complete CuFe1-xCrxO2 solid solution was studied by thermogravimetric analysis and high-temperature X-ray diffraction experiments under an air atmosphere up to 1000 C. For x = 0, CuFeO2 is oxidized into the spinel (CuFe2O4) and copper monoxide (CuO) phases, whereas for x = 1, CuCrO2 is thermally stable. For all of the intermediate compositions (0 < x < 1), complex oxidation, reduction, and phase transitions between delafossite and spinel have been observed. chromium tends to stabilize the stoichiometric delafossite phase, while iron favors the delafossite-to-spinel phase transition.