Effect of La3+ and Nb5+ on structural and mechanical properties of BaFeO3−δ

Effect of La- and/or Nb-doping on structure and elastic behavior of BaFeO3−δ at room temperature and 850 °C were studied and compared. The Comparison of the microstructures and grain size distributions of densified Ba0.95La0.05FeO3−δ (BLFO), BaFe0.9Nb0.1O3−δ (BFNO) and B0.95La0.05aFe0.9Nb0.1O3−δ (BLFNO) showed that Nb-doping hindered grain growth during sintering. The XRD analyses of sintered samples demonstrates that La-doping is more effective than Nb-doping for stabilization of high temperature symmetric cubic structure as it proved by BLFO’s linear elastic behavior in cyclic compression stress–strain curves. BFNO and BLFNO exhibited ferroelastic behavior at room temperature due to presence of non-symmetric phases in their structures. All samples showed linear elastic behavior at 850 °C with remnant strain due to high temperature creep deformations. Both La- and Nb-doping can improve creep resistance of BaFeO3−δ.