Abstract:

The sample 0f SrCoO3-δ was prepared by ammonium nitrate (NH4NO3) co-melted method and the structure of which was characterized by XRD and thermal analysis. The relationship between the oxygen nonstochiometry and the oxygen pressure and temperature was studied under the conditions of temperature 672 - 918 K and the oxygen pressure 0.7 - 59. 3 kPa. The model of the oxygen deficiency formation was firstly suggested and the mathematic formula describing the phase equilibrium of the SrCoO3 -δ-O2 system was given. The general applicability of the deficiency model was evaluated for the example of SrFeO3- δ. The enthalpy change and the entropy change of the SrCoO3-δ-O2 system in the process of dissolving oxygen were measured to be (75. 3 ±1. 2) kJ•mol-1 and (96. 7 ±1. 5) J•mol-1.K-1 respectively.

Key words: Strontium cobaltate complex oxide, Nonstoichiometry, Oxygen deficiency model, Enthalpy change, Entropy change