Ceramic and transport properties of halogen-substituted strontium ferrite

An attempt of fluorine and chlorine substitution for oxygen in strontium ferrite SrFeO3-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 SrFeO3-δ was recorded in materials with nominal compositions SrFeO2.8-δF0.2, SrFeO2.6-δCl0.4, and SrFeO2.4-δCl0.6. The strong effect of halogen addition on ceramic properties of oxides was revealed. While SrFeO3-δ was known for its poor sinterability, adding 0.2 mol of fluorine or chlorine during the synthesis of SrFeO3-δ was shown to result in successful obtaining gas-tight ceramics.