ИСТИНА

Water fluid is the active medium in the course of a formation of the complicated oxides structure. Nano-powders of lanthanum aluminate doped by europium and cerium were synthesized in water fluid under sub- and supercritical condition. Mechanical mixture of aluminum and lanthanum hydroxides was used as precursor. The small amount of europium oxide or cerium nitrate was added in the reaction mixture for doping of the synthesized product. The synthesis was carried out in two stages. The temperature of the first stage was equal to 200°C (PH2O = 1.5 MPa), the temperature of the first stage was equal to 200°C (PH2O = 22 MPa). The properties of synthesized doped lanthanum aluminate have been studied by Xray analysis, electron diffuse reflection spectroscopy, luminescent analysis and by SEM. The finish product of the synthesis was comprised of lanthanum aluminate with the crystal sizes 200 – 500 nm. The lanthanum aluminate doped by europium was characterized by an intensive luminescence near 590 and 620 nm. The state of the crystal structure of lanthanum aluminate was investigated after the embedding of the dopant ions in the crystal lattice of the complicated oxide. The cerium ions were used as dopant. The doping leaded to disorder of the aluminate structure. For pure lanthanum aluminate the size of regions of coherent X-ray scattering was equal to 53.3 nm. For doped lanthanum aluminate (1% Ce in reaction medium) this value was equal to 48,5 nm. The level of crystal lattice distortion was increased from 1.6·10-3 to 1.9·10-3.