Experimental determination of the eutectic temperature in air of the CuO-TiO_2 pseudobinary system

摘要

Eutectic temperature and composition in the CuO-TiO_2 pseudobinary system have been experimentally determined in air by means differential thermal analysis (DTA), thermogravimetry (TG) and hot-stage microscopy (HSM). Samples of the new eutectic composition treated at different temperatures have been characterized by X-ray diffraction (XRD) and X-ray absorption near-edge structural spectroscopy (XANES) to identify phases and to determine the Cu valence state, respectively. The results show that the eutectic temperature in air is higher by 100 °C (~ 1000 °C) for a Ti-richer composition (X_(TiO_2) = 25 mol%) than the one calculated in the literature. The reduction of Cu~(2+) to Cu~+ takes places at about 1030 °C. The existence of Cu_2TiO_3 and Cu_3TiO_4 has been confirmed by XRD in the temperature range between 1045 and 1200 °C.