Incorporation of barium in titanium oxide and lanthanum oxide

摘要

Two series of samples, noted TiBaX and LaBaX (where X=at. percent of Ba), have been prepared in neutral medium from TiO_2, La_2O_3, and gammaBaCO_3. These samples were calcined under air at 450 and 1150 deg C then characterized by X-ray diffraction (XRD), thermoreduction under H_2 and scanning electron microscopy (SEM). After hydrolysis the conversion of La_2O_3 in to La(OH)_3 is complete while TiO_2 is only partially hydrated. Obtained results show that after calcination at: (1) 450 deg C, barium is not inserted into the structure of TiO_2 while light interaction occurs between the barium and lanthanum; (2) 1150 deg C, it forms mixed oxides BaTiO_3 and BaTi_4O_9 for TiBaX and BaLa_2O_4 for LaBaX. The microscopy showed that these phases are better crystallized.