Crystal Structure and Anomalous Sintering Behavior of (Sr0.7La0.3)1-xTiO3+δ Perovskites (0 ≤ x ≤ 0.12) Synthesized by the Pechini Method

The crystal structure, phase relationship and sintering characteristics of (Sr0.7La0.3)(1- x)TiO3+delta perovskites (0 <= x <= 0.12) have been studied using the Pechini method. High-temperature neutron diffraction analysis showed that (Sr0.7La0.3)TiO3+delta has an orthorhombic structure at room temperature and a cubic structure at 450 degrees C. (Sr0.7La0.3)(0.88)TiO3+delta showed a single perovskite phase and other samples with an A-site deficiency of 0 <= x <= 0.08 included secondary Ruddlesden-Popper phases. Sintering characteristics improved as the A-site deficiency increased and it was found that during sintering, (Sr0.7La0.3)(0.88)TiO3+delta expanded anomalously between 1400 degrees C and 1500 degrees C and for holding times between 0 h and 10 h at 1400 degrees C and 1500 degrees C. Additionally, observation of the samples by scanning electron microscopy showed that this expansion was caused by pore formation within the samples. All the samples showed a weight decrease at temperatures >= 1000 degrees C and the temperature at which oxygen release began rose as the A-site deficiency increased. The release of oxygen is likely to be related to pore formation. [DOI: 10.1115/1.4005611]