Experimental and thermodynamic assessment of the fluoride-rich region in the Cu-O-F system.

A thermodynamic evaluation and optimization of the CALPHAD type of the Cu-O-F system, together with phase diagram measurements, are considered in the present work as the first step towards a complete evaluation of Cu in the multicomponent system Cu-Fe-Ni-Na-Al-Ca-O-F. Differential Scanning Calorimetry experiments were conducted using a closed crucible to identify the phase transitions in the CuF 2 -Cu and CuF 2 -Pt pseudo-binary systems in the presence of oxide impurities. The thermograms and the diffractograms, as measured by X-Ray Diffraction, showed that reactions occurred in both systems, where the CuO impurity from the CuF 2 reactant led to the formation of Cu 2 O after three or four runs. All new model parameters of the fluoride-rich region of the Cu-O-F system were optimized based on this study’s experimental results. Measured and calculated results are in good agreement and provide a new interpretation of the phase transitions reported in the literature. [ABSTRACT FROM AUTHOR]