Yermolayeva Y. Phase composition, structure and morphological stability of solid solutions (Lu1-xEux)2O3 (x=0.01-0.1) in size-limited state

Thesis is devoted to the development of the preparation technology of new low agglomerated monosized powders of two types: (1) based on spherical submicron particles of (Lu1-xEux)2O3 solid solutions and (2) based on combine "core SiO2/shell (Lu1-xEux)2O3" heteroparticles, which are have necessary quality for preparing on their basis photonic crystals for visible spectral range. The nanocovering of the ZnO with "island structure" and solid solutions (Lu1-xEux)2O3 (x=0,01-0,1) with thickness of 5-50 nm on the spherical SiO2 templates with diameter ?=300 nm was obtained by means of template synthesis during precipitation from water solutions with further low-temperature crystallization of initial amorphous nanolayer. It was established by microscopy and X-ray diffraction methods that "core SiO2/shell (Lu1-xEux)2O3" heteroparticles were stable till Т?900 ?С. At higher temperature (Т?1000-1200 ?С) interaction between the core and shell is initiated leading to formation of mixed ortho- and pyrosilicates (Lu1-xEux)2SiО5, (Lu1-xEux)2Si2O7 and to distraction of nanolayer uniformity (Т?1200 оС). Weakly agglomerated powders with monodisperse crystalline spheres (Lu1-xEux)2O3 (х=0,01-0,1) of controlled diameter in the range of ?=40-300 nm and dispersion of 10% were obtained by means of sol-gel method with further low-temperature crystallization (Т=600-900 ?С). The investigated structurally-morphological and phase transformations of the spherical particles in the process of annealing were investigated by means of thermal and X-ray diffraction methods, IR and Х-ray photoelectron spectroscopy etc.