Effect of Strontium on Structure and Superficial Area of La sub(2)O sub(3)

Recently, lanthanum oxide doped by group IIA elements may strongly influence solid state reaction. A series of samples, noted LaSrX (where X = % atomic of strontium) have been prepared by hydrolysis, in neutral medium from La2O3 and SrCO3. These samples were calcined under air at 450[symbolomitted]C and 1150[symbolomitted]C then characterized by specific surface area (BET), X-ray diffraction, scanning electron microscopy (SEM), thermogravimetry (TG) and differential thermal analysis (DTA). Obtained results show that after calcinations at: 1) 450[symbolomitted]C, the addition of strontium is without effect on surface of La2O3 and the XRD analysis revealed no interaction between lanthanum oxide and strontium carbonate; 2) 1150[symbolomitted]C, the sintering of the samples is very important, reduction of 70% of surfaces compared to the samples calcined at 450[symbolomitted]C; XRD results show that LaSrX are formed principally by two oxides: SrLa2O4 and La2O3, which is confirmed by SEM method. The reaction between La2O3 and SrCO3 showed three endothermic weight losses; elimination of water, a partial dehydroxylation of La(OH)3 and formation of La2O2CO3 and La2(CO3)3.