Evolución de fases de Ba 1-x Eu x Ti 1-x/4 O 3 durante el proceso de sinterizado en aire con Difracción de Rayos X in situ a alta temperatura

The phase evolution of Ba1-xEuxTi1-x/4O3 during the sintering process (heating and cooling) in the air with x = 0.0054, 0.0384, 0.1920, and 0.2689 mol% Eu2O3 was investigated by high temperature in situ X-ray diffraction in the range of temperature between 30 and 1200 °C. The samples were prepared mixing BaCO3, TiO2 and Eu2O3 powders using the solid-state method. The results obtained for the samples with x ≥ 0.2689 mol% Eu2O3 showed the cubic phase BaTiO3 doped with Eu3+ at 900 °C. Below 500 °C the tetragonal ferroelec­tric phase BaTiO3 doped with Eu3+ was detected. The secondary phase Ba2TiO4 was identified in the samples when heated to 1100°C with x = 0.0054, 0.0384 and 0.2689 mol% Eu2O3 and at 1200 °C for x = 0.1920 mol% Eu2O3. The secondary phases Eu2Ti2O7 and Eu2TiO5 were identified during cooling in the temperature range of 1200 °C to room temperature for the sample with x = 0.1920 and 0.2689 mol% Eu2O3. The results of high-resolution scanning electron microscope (HRSEM) showed a wide grain-size distribution, a partially homo­geneous microstructure and higher amounts of inter-granular porosity as well as a uniform incorporation and distribution of Ti, Ba and Eu in each sample.