Compositions of mixes have been developed to obtain tiles for interior wall cladding based on local raw materials: low-melting polymineral clay from the Gaidukovka deposit, dolomite from the Ruba deposit, granitoid screenings from the Mikashevichskoe deposit and quartz sand from the Gomel GOK, as well as refractory kaolin brand DNPK and imported from Ukraine KS-1. The properties, phase composition and structure of the tiles have been studied. The resulting ceramic tiles have high physical and chemical characteristics.
The results of thermodynamic modeling of solid-phase processes occurring during the firing of volumetric light-colored ceramic bricks obtained on the basis of refractory clay and artificial flux are presented. The results of thermodynamic calculations were confirmed with the help of X-ray studies of ceramic samples. The regularities of the process of phase formation of ceramic bricks made with the use of artificial flux are given.
The results of studying the creep of polycrystalline ceramics based on metal oxides at temperatures up to 1600 ° C and high loads are presented. These temperatures are in the vicinity of the transition from the brittle behavior of the ceramic to the plastic one. The loads are close to the ultimate strength of materials at a given temperature. It is shown that the elementary deformation mechanism in the entire plasticity range of the samples is the diffusion-viscous (vacancy or interstitial) flow with its varieties - the diffusion displacement of dislocations and crystal boundaries. The data obtained agree with the assumption that the transition from brittle fracture of ceramics to plastic in it requires the appearance of a certain critical concentration of vacancies. These vacancies are formed due to thermal activation and determine the deformation of materials. Tab. 1, ill. 3, bibliography: 7 titles.
The classification of grinding equipment and conditions affecting the process of mechanical processing of raw materials for the production of oxide ceramics is presented. Based on the analysis of grinding (dispersing) processes and mechanochemical activation of alumina, it is recommended to use mills with impact (pressure) - shear loading (drum, vibration, planetary, etc.). Optimal for achieving high values ??of specific surface area and degree of mechanochemical activation are mills with an average energy intensity of 3-10 kW / kg. Tab. 1, ill. 2, bibliography: 25 titles.
The features of sintering processes of ceramic materials of the Y - ZrO 2 - Al 2 O 3 system of various initial structural modifications (tetragonal or cubic) have been studied. The influence of the pressure of cold isostatic pressing on the bulk density of such materials subjected to high-temperature firing has been established. Il. 5, bibliography: 4 titles.
The spectrocolorimetric and luminescent characteristics of porcelain containing neodymium oxide additives have been studied. It has been shown that an increase in whiteness occurs when the content of neodymium oxide is low, and when it is increased, the coloration process begins. The increase in the whiteness of porcelain is explained by a combination of two optical effects: an increase in reflection in the blue-blue region of the visible spectrum, due to the appearance of sensitizing luminescence of the neodymium ion in the region of 390 - 480 nm and a decrease in yellowness associated with the absorption of the neodymium ion in the range of 560 - 590 nm and a shift in the reflection maximum into the blue-green region of the spectrum. Tab. 1, ill. 7, bibliography: 12 titles.
The development of crystalline phases (mullite, pseudo-cubic zirconium dioxide, and zircon), microstructure, linear shrinkage, apparent density, and compressive strength of ceramic samples obtained from powders after grinding and synthesis in a reactor using illite clay as a binding agent in depending on the temperature regime during spark plasma sintering.
The results of X-ray phase analysis indicate an intensive development of the mullite phase and pseudocubic zirconia in all samples with an increase in the sintering temperature, and the formation of a dense microstructure of the samples is also observed. Additionally, the linear shrinkage of the samples increases with an increase in the sintering temperature, as well as the apparent density and compressive strength of the samples with an increase in the grinding time up to 24 h and the introduction of clay into the samples, showing, respectively, the maximum values ??of 3.45 g / cm 3 and 252.0 MPa. Il. 7, bibliography: 19 titles.
In the temperature range 1400 - 1600 ° C, the deformation of polycrystalline oxide ceramics occurs due to the action of diffusion mechanisms. The course of the deformation curves is very sensitive to the presence of nonequilibrium defects and stress concentrators, which were "hardened" during the cooling process after high-temperature firing during the preparation of materials. Destruction occurs, apparently, as a result of the formation of vacancies in areas of the stretched zone, confined to the boundaries of the crystals, and then their coagulation at the boundaries. The course of the processes of formation and development of cracks is not the same for different materials and depends on their crystal chemical characteristics.
The possibility of obtaining expanded clay of low density and high strength from weakly expanding clay raw materials using a carbon-alkali reagent (UCHR) has been investigated. The features of the formation of the porous structure of expanded clay granules under various temperature and time conditions and its effect on the physical and mechanical properties of the material have been studied. Tab. 1, ill. 3.
A new method has been developed for the synthesis of ceramic composites based on Ti 3 SiC 2 using non-powder reaction compositions of titanium and silicon carbide. A ceramic composite with a matrix Ti 3 SiC 2 - TiSi 2 reinforced with SiC particles. The features of the phase composition and microstructure of the obtained material are investigated. Il. 4, bibliography: 13 titles.
