The results of a study of the dielectric properties and harmonic coefficient for barium titanate ceramics obtained from
a powder with a particle size of 50 nm at different sintering temperatures are presented. It is shown that ceramics from nanopowders can be produced at lower sintering temperatures than technical ceramics with a particle size of 1 µm. Ceramics obtained at a sintering temperature of 1200 ?C have the best linear and nonlinear dielectric properties.
Thermal insulation and composite foamed inorganic materials with a reduced thermal conductivity of 0,064…0,076 W/(m·K) have been developed on the basis of technogenic silica-containing raw materials. The influence of pore-forming and curing modifying additives on the structure, phase formation and physico-technical properties of foamed materials has been studied. It was found that the combined use of graphite and chalk leads to a decrease in the density of materials, the use of graphite and gypsum, graphite and sodium silicofluoride leads to an increase in the strength of materials.
The article investigates the physical, mechanical and technological properties of ceramic plates in the composition of Kulatau clay and dune sands of the Tuprakkala massif located in the lower amudarya region of the Uzbekistan. Under the conditions of laboratory and semi-production tests, it was found that, from the optimal composition M-7 at a firing temperature of 1000…1050 ?C, it is possible to obtain unglazed facade tiles and floor tiles. And from the optimal composition M-9 at firing temperatures of 1000…1050 ?C, it is possible to obtain facing and facade tiles with opaque glaze.
The effectiveness of using borate (borax) and fluoride (sodium fluoride) fluxes in the sintering of crystalline (sand) and amorphous (diatomite) silicate raw materials was considered. The change in the density and appearance of samples
with varying degrees of fluxes during their heat treatment at different temperatures was described. It was shown that
the introduction of 4 wt. % borax reduces the temperature to reach a density of 1500 kg/m3 by 100 °C, and 6 wt. % borax – by 200 °C. It was shown that the introduction of fluxes increases the amount of X-ray amorphous glass phase due
to depolymerization of the silicon-oxygen network and the formation of a low-temperature melt.
An overview of dielectric materials with high (more than 10 000) values of relative permittivity is presented. Most of the compositions of these materials are based on systems that include ferroelectric and non-ferroelectric components,
as well as solid solutions based on them. Various approaches to increasing the dielectric permittivity of materials are considered: doping, sintering atmosphere, grinding time, sintering temperature, grain size. The effect of dopants and the synthesis method on the value of characteristics of capacitor ceramics that can be used in the low-frequency and high-frequency range is compared.
The glass of 12.5Li2O–50GeO2–37.5P2O5 composition was synthesized by melt quenching. By means of its thermal annealing, single-phase LiGe2(PO4)3 composition was obtained, which is promising as a solid electrolyte for all-solid-state lithium-ion power sources. Using total X-ray scattering with analysis of the pair distribution function, and diffuse reflectance spectroscopy in the UV-Vis range, the local structure and optical properties of initial (amorphous) glass and crystallized glass were studied. An assessment of the influence of the effect of glass crystallization on these properties was carried out. It has been shown that structuration in the glass is observed only at the level of the first-second coordination sphere of Ge and P atoms. From the optical absorption spectra of the initial glass, the presence of F+ centers in the glass has been revealed, and their concentration decreases as a result of glass crystallization. The estimated value of the band gap for the crystallized glass, i.e. for the LiGe2(PO4)3 phase, is 6.15 eV for the case of direct allowed transitions, which exceeds the calculated value known from the literature by approximately 2 times.
Within the scope of the study, glasses co-doped with Sm3+/Gd3+ in the B2O3–GeO2–Bi2O3 system were synthesized,
covering compositions of 40B2O3–40GeO2–(15…17)Bi2O3–(3…2)Sm2O3–(2…1)Gd2O3 and 42,5B2O3–42,5GeO2–(11,25…12,75)Bi2O3–(2,25…1,50)Sm2O3–(1,500…0,075)Gd2O3. An assessment of luminescent characteristics was
conducted within the temperature range of 298 to 673 K. Spectral bands of photoluminescence associated with transitions between various Stark sublevels of Sm3+ ions were identified. Redistribution of the fluorescence intensity ratio corresponding to transitions 4G5/2 ? 6H9/2 ( = 645 nm) and 4G5/2 ? 6H7/2 ( = 597 nm) was observed. Based on the obtained
data, calculations of the fluorescence intensity ratio FIR, as well as relative sensitivity SR, were performed. The obtained results indicate the promising potential of these glasses as luminescent thermometric materials.
The features of glass batch preparation in the production colorless sheet glass with increased transparency are considered. A non-standard algorithm for dosing and loading selenium, cobalt oxide, erbium oxide and iron oxide into the mixer
was proposed.
A method for measuring the resistive characteristics of channels in the blanks of microchannel plates has been developed. Two probes are used for measurements, which minimizes leakage currents through adjacent channels.
The resistive properties of single channels of the microchannel insert of the restored blank of the microchannel plate MKP 18-10 have been studied. It is established that the resistance of the channels depends on their position in the microchannel honeycomb. It is shown that the channels located in close proximity to the monolithic frame have less resistance compared to those located in the middle of a stranded glass honeycomb.
It was found that it is possible to obtain high-strength ceramic paving stones based on loess rocks with the addition of 20 % glass waste powder. At the same time, the amount of moisture in the ation should be close to 10 %, which corresponds
to the semi-dry pressing technoloformgy.
