Investigations of changes in the phase composition and structure of modern ceramic materials under the action of a high-intensity light flux have been carried out. For the experiment, the technological capabilities of a unique installation - the Large Solar Furnace - were used. It is shown that the surface treatment of the ceramic material of the Al 2 O 3 -SiO 2 system with a highly concentrated energy source leads to the appearance of two new phase components - & # 945 ; -Al 2 O 3 and cristobalite. Reflow material processing contributes to the formation of the eutectic component
The synthesis of an inorganic heat-insulating material - glass-foam ceramics with the use of activating methods for preparing a charge in the form of its extrusion and autoclaving is considered. The interaction of the amorphous phases of the opalcristobalite rock with NaOH intensifies, resulting in a significant decrease in the average density of the material. The economic effect is achieved due to a proportional reduction in the content of expensive sodium hydroxide in the material. The introduction of an additive for container cullet into the charge contributes to an even more significant decrease in the average density of samples and a reduction in the consumption of NaOH, and, consequently, to a reduction in the cost of foam glass ceramics.
It is shown that the addition of antimony oxide to the composition of the lithium-aluminosilicate glass of the sitall-forming composition makes it possible to suppress the often observed effect of glass cracking during its crystallization at temperatures above 700 ° C. It was found that the introduction of Sb 2 O 3 does not change the phase composition of the resulting sitall. A scenario of the introduction of antimony atoms into the residual glass phase is proposed, which describes the observed effect
The sol-gel method was used to synthesize glass ceramics based on the compositions of the Sr (Ba) - Al 2 O 3 - SiO 2 systems, modified with the addition of zirconium oxides ZrO < sub> 2 and hafnium HfO 2 in the presence of stabilizing yttrium oxide and without it. It is shown that the introduction of refractory oxides contributes to a reduction in the gelation time of the initial solutions, intensifies the sintering of glass ceramics, and also leads to a change in the temperature ranges of the phase formation processes and the nature of the precipitated crystalline phases. The use of the sol-gel method made it possible to ensure a uniform distribution of modifier oxide grains in the volume of glass ceramics. Yttrium oxide in the structure of materials is concentrated near ZrO 2 and HfO 2 particles
Using thermodynamic calculations, the sequence of formation of crystalline phases during heat treatment of composite mixtures glass 0.5MgO 0.2BaO 0.3 2 O 3 ? kaolin. It is shown that the primary crystalline phase is Celsian, and the secondary? cordierite
A transparent glass-ceramic containing nanocrystals of lead fluoride ?-PbF 2 with Er 3+ ions (average diameter 8.5 nm) was synthesized by secondary heat treatment of the initial oxyfluoride glass of the system SiO 2 - GeO 2 - PbO - PbF 2 doped with Er 2 O 3 . Its thermal and structural properties, optical absorption, and up-conversion luminescence have been investigated. The obtained glass-ceramics is promising as a phosphor, it allows one to obtain an intense yellow glow upon excitation in the infrared range of the spectrum.
The processes of crystallization and sintering, occurring during firing, during the production of strontium-anorthite glass-ceramics by the method of powder technology, have been studied. The character of the influence of the dispersity of the initial glass powders and the temperature-time conditions of firing on the temperature and heat of crystallization, the nature of the precipitated phases, the temperature range and the kinetics of particle sintering is shown. It has been revealed that for the glass composition undergoing vitrification, there is a narrow range of powder dispersion, on the basis of which, using a multistage heat treatment regime, it is possible to obtain densely sintered materials of the required composition with high mechanical characteristics.
