Thermal stability of CaCu3Ti4O12: Simultaneous thermal analysis and high-temperature mass spectrometric study

Thermal stability of calcium copper titanate was studied by differential scanning calorimetry, thermogravimetry and high-temperature mass spectrometry. Calcium copper titanate (CCTO) had no thermal effects and mass losses caused by thermal dissociation or any phase transitions, besides melting, in the temperature range of 298-1423 K. The melting point of calcium copper titanate is 1398 K. The endothermic effect at 1250 K was associated with the decomposition of copper (II) oxide segregated in the intergrain space of the CaCu3Ti4O12-CuO ceramics. In this connection, we proposed a simple method for estimating the content of copper oxide in the CaCu3Ti4O12-CuO composite. The processes of evaporation of CaCu3Ti4O12 in the temperature range of 1500-2100 K were studied by high-temperature mass spectrometry. In the temperature range of 1500-1750 K, easily volatilized copper oxide was evaporated selectively from the calcium copper titanate. At the temperature of 2100 K, atomic calcium and titanium oxides, TiO and TiO2, were present in the vapor.