A Comparative Study of High Temperature Properties of Cobalt-Free Perovskites

J. BASBUS; F. PRADO; L. MOGNI; A. CANEIRO

JOURNAL OF ELECTROCERAMICS

SPRINGER

Lugar: Berlin; Año: 2014 vol. 32 p. 311 - 318

1385-3449

The Co-free perovskites with chemical composition Ba0.5Sr0.5Fe0.8M0.2O3-δ (M = Ni, Cu, Zn) were synthesized by the modified Pechini method and the structure and microstructure characterized by XRD and SEM. Oxygen content, electrical resistivity and Thermal Expansion Coefficient (TEC) were evaluated in air between room temperature and 900 °C. The high temperature properties of these perovskites are compared with those of Co containing Ba0.5Sr0.5Fe0.8Co0.2O3-δ perovskite. The Ba0.5Sr0.5Fe0.8Ni0.2O3-δ composition is reported for the first time in the present work. The highest electrical conductivity was obtained for Ba0.5Sr0.5Fe0.8Cu0.2O3-δ with a value of 47.6 Scm-1 at 544 °C. This composition shows the highest oxygen vacancies concentration, being the oxygen content 3-δ = 2.61 at room temperature. Despite the good high temperature properties of these compounds, degradation of Ba0.5Sr0.5Fe0.8M0.2O3-δ compounds occurs at room temperature in samples stored in air.