Thermodynamic stability of SrCeO3

Thermochemistry of the reaction between SrCO3 and CeO2 as SrCO3 (S) + CeO2, (s) = SrCeO3 (S) + CO2 (9) was studied over the temperature range 1113-1184K. The equilibrium pressure Of CO2(g) over the ternary phase mixture of SrCO3(S), CeO2(s) and SrCeO3(S) was measured at various temperatures using a tensimetric apparatus. The temperature dependence of the measured CO,(g) pressure could be represented as Log (p(CO2), (Pa)) (+/- 0.04) = -11534(+/- 750)/T+13.1(+/- 0.7), (1113 less than or equal to T (K) less than or equal to 1184). Tensimetric measurements were also carried out for the decomposition of SrCO3(S). The equilibrium vapor pressures of CO2(g) over the biphasic mixture of SrCO3(s) and SrO(s) could be represented as Log p(CO2) (Pa) (+/- 0.01) = - 11139(+/- 263)/T+12.72(+/- 0.2), (1045 less than or equal to T (K) less than or equal to 1123). The observed CO, pressures were compared with those obtained for reaction (1). Simultaneous thermogravimetric/differential thermal analysis experiments were carried out for reaction (1) and for the decomposition of SrCO3 in CO2 atmospheres. All these results were used to derive the thermodynamic properties of SrCO3(s) and SrCeO3(S). (C) 2004 Elsevier Inc. All rights reserved.