Hydrothermal synthesis and characterization of LaCrO3

The synthesis of perovskite-type LaCrO3 under mild hydrothermal conditions is reported. The synthesized product was characterized by means of XRD, IR, SEM and elemental analysis. The results indicated that the phase correspon ded to orthorhombic perovskite-type LaCrO3, and the product had a narrow pa rticle size distribution in the range of 1-3 mu m. The effect of hydrotherm al conditions on the synthesis of LaCrO3 was investigated. Under the hydrot hermal conditions used, the optimum crystallization temperature was 240-260 degrees C. For the formation of pure LaCrO3, a higher alkalinity (greater than or equal to 8 mol dm(-3) KOH) is necessary because Cr3+ is significant ly amphoteric. In the reactant mixing process, the optimum stirring time is 5-10 min because of the oxidation of CrO2- ion by oxygen in the air. CrO42 - does not show significant hydrothermal reactivity under the present condi tions.