Vaporization and thermodynamic activities in La0.80Sr0.2-xCaxCrO(3-delta) , x=0.05, 0.10 and 0.15, investigated by Knudsen Effusion Mass Spectrometry

摘要

Vaporization of the perovskite phase La0.80Sr0.2-xCaxCrO3-delta, x = 0.05, 0.10, and 0.15, was investigated by the use of Knudsen effusion mass spectrometry in the temperature range 1900 to 2100 K. The partial pressures of Cr(g), CrO(g), CrO2(g), CaO(g), Sr(g), SrO(g), and LaO(g) were determined for all the samples investigated at 2000 K. The partial pressure of O-2(g) was, in addition, evaluated from the gaseous equilibria. The equilibrium partial pressures were used for the calculation of thermodynamic activities of the components at 2000 K. The results were compared with thermodynamic data for La1-xMxCrO3-delta, M = Ca,Sr. (C) 2001 The Electrochemical Society.