Ceramic and transport properties of halogen-substituted strontium ferrite

An attempt of fluorine and chlorine substitution for oxygen in strontium ferrite SrFeO_3–δ was undertaken in search of a new means of influence on the oxide properties. An uncontrollable removal of halogen-ions from oxides during synthesis was detected. Nevertheless, residual halogens were found to provide a notable impact on ion conductivity and oxide stability under reducing conditions. More than twice higher ion conductivity relative to SrFeO_3–δ was recorded in materials with nominal compositions SrFeO_2.8–δF_0.2, SrFeO_2.6–δCl_0.4, and SrFeO_2.4–δCl_0.6. The strong effect of halogen addition on ceramic properties of oxides was revealed. While SrFeO_3–δ was known for its poor sinterability, adding 0.2?mol of fluorine or chlorine during the synthesis of SrFeO_3–δ was shown to result in successful obtaining gas-tight ceramics.