solid solutions

Relevance of the development of high-strength glass-ceramic coatings obtained by resource-saving technology for protective elements has been established. Structure formation mechanism in magnesium aluminosilicate glasses during heat treatment has been analyzed. Selection of the system was substantiated, model glasses and glass-ceramic materials on its base have been developed. Patterns of structure regularity and formation of the phase composition of glass-ceramic materials during their ceramization have been investigated.

The character of the interaction in the TlAs2Se3Te–TlAs2Te3Se system was studied by the methods of DTA, RFA, MSA, and also by measuring the microhardness and determining the density. State diagram of the system was constructed. It was established that the TlAs2Se3Te–TlAs2Te3Se system is partially a quasibinary section of the quaternary As, Tl//Se, Te system. One congruently melting compound TlAs2Se2Te2 is formed in the system at 548 K.

Liquid phase technologies for high-grade ceramic oxide powders of technical purpose and methods of their modification have been developed. On the basis of physico-chemical research methods various mechanisms of modifying processes have been analyzed. Substitution of the main ions by doping ones occurs in complex oxide powders followed by the formation of solid solutions. A powder which was obtained via TiO2 modification by sulfur has a surface layer in which sulfur forms chemical bonds.

Phase relations in the Tl5Te3-Tl9SbTe6-Tl9TbTe6 system were experimentally studied by DTA, XRD technique and microhardness measurements. Several isopleth sections and isothermal section at 760 K, as well as projections of the liquidus and solidus surfaces were constructed. It is determined that the system is characterized by an unlimited solubility of components in the solid state.

Complex oxides with perovskite structure RFeO3, where R are rare earth metals, represent an important class of functional materials. RFeO3 compounds are used in thermoelectric devices, solid oxide fuel cells, as membranes for partial oxidation of methane and oxygen cleaning, as catalysts for CO oxidation and decomposition of NOx, and as sensory materials.

There are formulated the key systems of equation describing  structurally nonhomogeneous two-component solid solutions.  As the key functions there are chosen the stress tensor (displacement vector) and the densities of admixture and skeleton.  On this basis the near-surface nonhomogeneity densities of skeleton and admixture, stresses and  size effects of surface tension and intensity of the power load causing the thin film fracture are studied.  The attention is paid to the admixture influence on size effects.