Ceramics is widely used as a material for impact protection due to its mechanical properties and density, which provide high specific strength of barriers. The main function of the barrier is to prevent structural failure of the protected object. The choice of specific ceramics for barriers depends on the mass, ability to absorb impact energy, resistance to multiple impacts, etc. A review of criteria and methods for evaluating the properties of ceramic materials intended for protection against impact loads is given. The existing selection criteria can be divided into two groups: criteria based on the physical (fundamental) properties of the material and criteria for evaluating the service properties of barriers. There are also experimental methods for evaluating the quality of barriers. It is shown that the coefficient of relative penetration of the indenter, proposed by V.Ya. Shevchenko, is universal, taking into account the properties of the penetrating body and allowing to construct a reliable representative series for most ceramic materials in brittle fracture.

The paper presents experimental data on the physical and mechanical properties of cellular materials with the geometry of triply periodic minimal surfaces (TPMS). It has been established that the dependence of the strength and Young’s modulus on the relative density of materials with the TPMS geometry corresponds to the Gibson – Ashby equation with a fairly high accuracy. Such materials are superior in mechanical properties to classical cellular materials and have high isotropy of mechanical properties.

A method is developed for producing primary catalyst carriers in the form of honeycomb blocks using additive technologies. The composition of the molding slip is developed and its rheological properties are optimized. Block catalysts based on primary supports formed by 3D printing are obtained. It is shown that these products are highly productive in the process of the catalytic oxidation of CO with atmospheric oxygen and it is possible to further increase it due to the formation of channels of complex geometric shapes, which make it possible to intensify the processes of heat and mass transfer.

The results of a comparative study of the optical properties of the thin films of zinc oxide ZnO, taking into account the influence of their copper doping, are presented. Using the experimental spectra of optical transmission, spectral dependences of the refractive and extinction index of the studied material, as well as components of complex dielectric permittivity constant, were calculated. The revealed features of the obtained dispersion curves are associated with the behavior of the impurity injected into the ZnO matrix.

—The effect of electron-beam treatment (EBT) and heat treatment (HT) of silica-based aggregates and mineral additives in Portland cement mortars on the intensity of alkali-silica reactions (ASRs) with their participation, which are dangerous for concrete structures, is studied. It is established that heating to a temperature of 900°C and the EBT of sand free of alkali-reactive inclusions, leads to a significant increase in the reactivity of cement-sand mortar mixtures, which increases with an increase in the absorbed dose and a corresponding increase in the content of acid hydroxyl groups on the sand surface. In the case of sand containing reactive inclusions of chalcedony, EBT leads to an increase in reactivity, and HT, to a decrease. Treatment of microsilica and metakaolin mineral additives capable of ASR inhibition leads to an increase in their inhibitory effect. The results obtained are promising for modeling the expansion of concrete as a result of ASR and increasing their resistance to fracture in alkaline media.

An approach is proposed to reduce the stability of the cubic phase of lead selenide by thermal oxidation with atmospheric oxygen and its transformation into an ordered monoclinic phase of lead selenite. An estimated thermodynamic analysis (TA) of the course of possible chemical reactions of lead selenide oxidation with oxygen is carried out. The kinetics of lead selenide oxidation with atmospheric oxygen are studied by X-ray emission analysis, X-ray diffractometry, optical reflection in the infrared region of the spectrum, studies of conductivity in direct and alternating currents, and nuclear magnetic resonance. For the PbSeO3 structure, the Goldschmidt stability factor was estimated and it was shown that the structure can be classified as perovskite-like and have ferroelectric properties.

To improve the characteristics, samples of diamond–carbide silicon composite were subjected to microwave processing. The products were placed in a microwave oven chamber, in a zone with maximum electric field intensity. As a result of processing, it was possible to increase the density of samples by 7

This paper studies the resistance to oxidation of various grades of commercial diamond powders. The kinetics of diamond oxidation in air is studied by optical and electron microscopy, as well as X-ray microscopic and thermal analysis. The relationship between the size of diamond grains, their morphology, and their impurity composition with temperature, heat release, and the rate of the process is studied. It is established that the main factor affecting the behavior of diamond during its combustion is the type of impurities present in the powders, followed by the grain size and its morphology. A complex multistage nature of the oxidation process is discovered.

В работе впервые проведено моделирование реакционно-диффузионных процессов, обеспечивающих формирование композиционного материала алмаз–карбид кремния, имеющего уникальную упорядоченную микроструктуру.

Based on X-ray photoelectron spectroscopy and X-ray diffraction data for zinc oxide powders prepared via mechanical milling in an attritor, we have identified inherent features of the chemical binding of carbon dioxide on the surface of the powders. The results thus obtained can be used in the fabrication of carbon dioxide sensors, catalysts, and photocatalysts with improved performance parameters. The powders milled for 3 h exhibit the most active interaction with atmospheric carbon dioxide and have the largest percentage of carbon chemisorbed in carbonate-like form.

Представлены результаты исследования спектров оптического поглощения в тонких пленках оксида цинка ZnO, полученных методом реактивного катодного распыления. Наблюдаемое поглощение света в области энергий фотонов, меньших ширины запрещенной зоны, объясняется присутствием в запрещенной зоне хвостов плотности локальных состояний. Определены ширина запрещенной зоны и характеристическая энергия Урбаха. Установлено влияние особенностей структуры и примесного фактора на поведение полученных экспериментальных спектральных зависимостей. Ключевые слова: оксид цинка, ширина запрещенной зоны, модель Тауца, энергия Урбаха.

The optical absorption spectra of zinc oxide (ZnO) thin films formed by reactive cathode sputtering are studied. The observed absorption of light in the region of photon energies lower than the band gap is explained by the presence of tails of localized states in the band gap. The band gap width and the characteristic Urbach energy are determined. The influence of the structural specific features and the impurity factor on the behavior of the experimental spectral dependences is determined.

An approach to the study of the relationship between the composition, structure and properties of composites is suggested on the basis of statistical analysis of the distribution of structural elements of the composite between its cross-section fragments and determination of fractal parameters as quantitative characteristics of the material structure. The prospects of this approach are demonstrated on the example of analyzing the microstructure of composites based on cyanoethyl ester of polyvinyl alcohol (CEPVA) with a ferroelectric filler barium titanate (BaTiO3), modified by the precipitation of fullerenol C60(OH)42. The filler modification is shown to result in a decrease of the span and standard deviation of the number of particles between the fragments of the composite, increase in the average number of particles in the fragments, a decrease in the lacunarity of filling the polymer matrix with the filler particles, and increase in the intensity of all the lattice density distribution maxima and correlation radii starting from the second maximum. The obtained results indicate a significant improvement of the filler particles distribution uniformity in the binder and prevention of their agglomeration, thus providing an increase in the permittivity of the composites by an order of magnitude and making the studied materials promising for the application in electronic devices.