Metallurgical Physicochemistry Division, Northeast University of Technology, 110006, Shenyang, China
Abstract:
In this investigation, nonstoichiometries and defect structures of tin oxides were studied between 694 and 990 K by coulometric titration using solid state electrolyte (YSZ) cells. The relationship between nonstoichiometry of the oxide (x) and equilibrium oxygen partial pressure (Po2) was expressed by the proportionality: xPO2?1/6. An intermediate oxide phase, Sn3O4 between Sn and SnO2 was observed in the temperature range of 696–732 K. The standard Gibbs energy of formation of Sn3O4 via the reaction;
was found to be ΔGoSn3O4 = ?1163960+417.36 T (J/mol). The standard Gibbs energy change for the defect formation reaction in SnO2?x was calculated to be ΔGoSnO2?x = 3.05×105?38.97 T (J/mol)).