Molten salt synthesis of anisometric Sr3Ti2O7 particles

Sr3Ti2O7 was synthesized in a KCl flux via molten salt process. SrTiO3 was formed first during the synthesis process, followed by the formation of Sr3Ti2O7. Product with Sr3Ti2O7 as the main phase was obtained at 1200 °C. The formation of Sr3Ti2O7 particles with platelet morphology was discussed based on the anisotropic property of the layered perovskite structure. The heating/cooling conditions influence the morphology of Sr3Ti2O7 greatly. Slow-heating and slow-cooling rates are beneficial to provide an approximate equilibrium growing environment for obtaining relatively large platelet Sr3Ti2O7 particles with high aspect ratio. Platelet Sr3Ti2O7 particles with an edge length of ∼10–35 μm and thickness of ∼2–5 μm were obtained at a heating rate of 0.5 °C/min and cooling rate of 0.5 °C/min. The growth mechanism of Sr3Ti2O7 was interpreted as two-dimensional nucleation.