VOL 95, No. 12 (2022)

Based on glass in the SrO–Al2O3–P2O5–SiO2–F system, functional glass fillers for glass ionomer cements containing up to 13 wt. % fluorine were obtained. The high level of radiopacity of the filling material is due to the presence of the absorbing component of the glass filler - oxide and strontium fluoride, which are introduced into the glass together. The use of fusible fluorine-containing raw materials makes it possible to reduce the glass transition temperatures, which opens up prospects for the industrial development of the developed compositions at melting temperatures below 1500 °C. The value of the refractive index of glasses with a high fluorine content nD ~ 1.50 is more in line with the refractive index of the polymer matrix of glass ionomer cement, which ensures high aesthetic characteristics of the filling material. Samples of transparent filling glass ionomer cement with high compressive strength > 100 MPa and hardening time of 5 min were obtained.

Dental composite ?lling materials based on glass in the SrO–Al2O3–B2O3–SiO2 system was obtained. The glass filler meets the modern level of requirements for filling materials, and is characterized by high chemical resistance to water, acids and alkalis (class I), high transparency (more than 80 %), consistency with the polymer matrix according to CTE while maintaining of an acceptable melting temperature and no tendency to crystallization. It is shown that the developed glass filler provides a high level of biomedical, operational and functional properties of a dental composite based on it and competitiveness with respect to popular foreign analogue materials.

In the paper presents an overview on the topic of obtaining high-temperature (HTCC) and low-temperature (LTCC) ceramics. The topic observe transition from a high-temperature process of obtaining ceramic materials to a low-temperature. Typical LTCC production process and the characteristics and properties of a “classic” glass ceramic composite described hereof. The main directions of application glass ceramics obtained by LTCC technology are shown.

The project is devoted to the study of the ceramic properties of the Orenburg region clay in order to determine the fields of its application in industry. Mineral, chemical, disperse compositions, as well as the sintering properties of the clay sample are determined. It was found that clay of the Orenburg region (Russian Federation) is the main clay with a high content of coloring oxides, medium dispersion, moderate plasticity, good drying, little sensitive to drying. The mineral composition of clay is determined. The main phases are kaolinite, smectite, illite, and quartz. The possible areas of using clay in the ceramics production are determined. This clay can be used to produce ceramic tiles of groups AII (b-1, b-2), AIII, BII (b), BIII in accordance with GOST 13996–2019, ceramic bricks of grade M200 and higher in accordance with GOST 530–2012, and to produce ceramic tiles in accordance with GOST 56688–2015.

Ceramics was obtained from the mixture of ZnO, SnO2 and TiO2 nanopowders by the method of solid-state sintering at 1123 K and 1443 K. The indicated nanopowders are used as components in arc dampers and for dispersion-strengthening in silver-based electrical contact materials. The phase formation and microstructure of the obtained material were studied by the methods of scanning electron microscopy, energy dispersive microanalysis and X-ray phase analysis. It is shown that at a sintering temperature of 1123 K a dispersed structure was formed, with the size of the Zn2TiO4 and ZnO phases being 0.5 – 1.0 µm. The solid phase reactions in the system ZnO/TiO2 at Тsint = 1123 K resulted in the formation of two-phase ceramics ZnO/Zn2TiO4 with the residual amounts of the phases of zinc and tin oxides. At Тsint = 1443 K there occurred the grain growth, Zn2SnO4 became the predominant phase and there remained a certain amount of the zinc and tin oxide phases.

The values of surface charges and zero charge points in water-clay suspensions with pH equal to 5, 7 and 9 have been studied. Their changes under the influence of a microwave field and variations in particle dispersion have been determined.
Powders of two fractions of montmorillonite, polymineral and kaolin clays of the Orenburg region were selected as objects of research. The determination of the TNZ of natural clays was carried out by the method of weight titration, based on the measurement of the pH limit value with an increase in the weight fractions of clay. Processing of clay powders in a microwave field was carried out according to the following mode: output power of 750 watts, operating frequency of 2.45 GHz, exposure time 600 s. The magnitude and sign of the charges formed at the interface of the surface of the electrolyte solution particles depend on the mineralogical compositions of the particles.
The fine fractions of two clays – montmorillonite containing and polymineral – were sensitive to treatment in the microwave field; the pH values of TNZ shifted to the acidic region by 0.26 and 0.31 units, respectively (by 4 %). The pH values of the TNZ suspensions with kaolin clay after treatment in microwave radiation practically did not change. If the pH value of the solution surrounding the particle exceeds the pH of the TNZ, then the sorbent will be able to absorb cations if the pH value of the solution is lower than the pH of the TNZ – anions.
The results obtained will allow the use of microwave exposure as a tool that expands the pH range, contributing to the effective sorption of anions and cations.

As a result of a comprehensive study of the characteristics of the clay of the Gurlensky deposit, it was determined that the Gurlensky hydrosluidic clay, in its chemical composition, has a relatively high content of iron oxide and alkaline oxides, as well as fine dispersion and a small amount of finely dispersed free quartz, which give this clay fusibility.
It has also been established that the clay of the Gurlensky deposit can be used in the development of ceramic compositions as a low-temperature fluxing component, instead of cullet, erclez, nepheline syenite, etc.

Thin luminescent films of the organometallic complex of lithium 8-hydroxyquinolate (Liq) on glass substrates were fabricated by capillary deposition and lithography. A study of the spectral-luminescent properties of the obtained film structures was carried out. The analysis of the surface of the films was carried out. The light yield and the kinetics of scintillation emission of the obtained film structures are estimated.