Influence of Ca2+ substitution on thermal, structural, and conductivity behavior of Bi1−xCaxFeO3−y (0.40 ≤ x ≤ 0.55)

• Published in: Journal of thermal analysis and calorimetry 2014-10, Vol.118 (1), p.255-262
• Main Authors: Thakur, Samita, Pandey, O. P., Singh, K.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Measurement Science and Instrumentation; Physical Chemistry; Polymer Sciences
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-014-3981-2

Bi 1−x Ca x FeO 3−y (0.40 ≤  x  ≤ 0.55) perovskite oxides have been synthesized by solid-state reaction method to study their properties as a cathode material for intermediate temperature solid oxide fuel cells. The as prepared samples were characterized by X-ray diffraction, differential thermal analyzer/thermogravimetry, dilatometer, and impedance spectroscopy to study their structural, thermal, and electrical properties. The Rietveld refinement results confirmed that all the samples exhibit tetragonal structure with P 4 mm space group. In addition to this, sample x  = 0.55 exhibits Ca 2 Fe 2 O 5 as a secondary phase. It has been observed that lattice parameters decrease with increase in calcium content. The thermal expansion coefficient and ionic conductivity increases with increase in calcium content up to x  = 0.50. The highest ionic conductivity is observed for Bi 0.5 Ca 0.5 FeO 3−y i.e. 1.71 × 10 −2  S cm −1 .