Engineering and Technology Journal

Lanthanum doped Ba1-xLaxTiO3 (BLT) with ( x = 0.005, 0.015, 0.02, 0.025) and undoped Barium titanate BaTiO3 (BT) nanopowders were synthesized at Room temperature via a semi-oxalate method with adjusting a pH of the solution around (5.5).Crystallization processes and Particles size of prepared powders were studied, measured and calculated by using X-ray diffraction. XRD analysis and Scanning Electron Microscopy SEM techniques, and the particles size was found to be about 65 nm. The dielectric properties (real є' and imaginary є" part of dielectric constant) of polymer/BT, polymer/BLT nanocomposites, and UPE (unsaturated polyester resin) samples were studied at different frequencies in the range of (20kHz-5MHz) using LCR meter, while theoretical dielectric constant of the prepared samples were calculated by using Bruggeman rule of mixture. The results of dielectric measurements found that the real dielectric constant and tangent loss of the nanocomposites samples decreases with increasing Lanthanum content.

Single crystalline BaTiO3 (BT) was prepared using TiCl4, BaCl2 and oxalic
acid. The structure of the prepared nanocrystalline BT powders were a tetragonal
perovskite according to XRD and HRTEM analysis. Annealing powder to 750oC
show that pure BT phase was formed according to XRD, TG, and FTIR
spectroscopy. The TEM images of the prepared powder reveal spherical
morphology of BT, while a finger twin, dendritic and embryo shape are observed
of BT powder calcined at 230, 530, and 750oC respectively. SAED and HRTEM
images showed a high crystalline BT powder and a single crystalline BT
respectively.