Vol 73, No 9-10 (2017)

The thermal properties of a series of synthesized rubidium and cesium borosilicate glasses were studied by means of differential scanning calorimetry. The vitrification and crystallization temperatures and the change in the specific heat capacity of these glasses at the vitrification temperature were determined. The thermal data were compared with the results of an investigation of the structural particularities by means of IR spectroscopy. The information obtained made it possible to adjust the heat-treatment parameters for glass-containing materials as a function of their composition; this is important in order to improve glassy matrix materials for the immobilization of radwastes.

The particularities of structure formation and the properties of ceramic brick, as a function of the content of calcium carbonates and iron oxides, based on clay raw material of different chemical-mineralogical composition in the case of low-temperature firing were determined. The carbonate and iron impurities are found to affect the strength properties.

The objective of the present research is to study the mechanisms of structure and phase formation of composite ceramic based on aluminum and silicon oxides in the process of SHS in the system Al–SiO₂. The possibility of obtaining Si in the composition of composite ceramic with crystals of size up to 500 μm is demonstrated.

An approach to obtaining data on the tortuosity k_Z of polyspherical media with ordered packing of spheres, characterized by definite values of the porosity ω and/or packing density γ, is shown using models of quasi-faceted cells and tubular pores. Presented in the form of graphical and analytical dependences these data make it possible to judge the value of k_Z for a granular medium on the basis of the actual value of ω and/or γ for it.

Glass samples were synthesized using raw materials from the Ural region and decolorizing agents; the chemical composition was picked as for fire-polished float glass. A glass complex additive was proposed for decolorization: cerium oxide and potassium nitrate. The spectral characteristics of the experimental glasses were studied and are presented. The maximum light transmission was reached at 750 nm and equaled 93%.

The results of an investigation of the processes occurring during heating and isothermal soaking at 450°C in the presence of an electric current flowing through a sample of S87-2 lead-silicate glass, widely used in electronics, are presented. The dependence of the electric conductivity on the temperature and annealing time with a continuous unidirectional current flowing through the sample as well as an alternating current, excluding electro-mass-transfer, are obtained. The results can be used to improve existing and create new technological processes for the production of electronic parts using lead-silicate glass.

The influence of ultrasonic processing (22 kHz) of a suspension of metakaolin, aluminum oxide, and sodium hydroxide with molar ratio Al₂O₃ · 2SiO₂: NaOH : Al₂O₃ = 6 : 12 : 2, followed by heat-treatment and hydrothermal crystallization on LTA zeolite synthesis, is investigated. It is found that by increasing the S : L ratio at the ultrasonic processing stage it is possible to increase the yield of the desired product. The optimal conditions of ultrasonic processing are determined (amplitude 8 μm, time about 10 min). It is shown that under the optimal conditions the degree of crystallinity of LTA zeolite equals 98%. The mechanisms of LTA zeolite synthesis by means of ultrasonic processing and mechano-chemical activation are compared.

A 3D-matrix is obtained on the basis of sintered composite material from bioactive glass and dicalcium phosphate. The effect of the component ratio of the mix and the firing temperature of the blanks on the phase composition, porosity, strength, and dissolution kinetics of sintered samples is determined. It is shown that directed formation is possible in sintered composites of highly resorbable phases. 3D-Modeling is used to obtain a personalized implant.

Glass ceramic composite protective technological coatings were developed in the systems Na₂O–B₂O₃–SiO₂ and BaO–Al₂O₃–SiO₂ for deformation of intermetallic alloys in the systems Ti–Al–Nb and Ni–Al–Co under isothermal conditions in air. The physical-chemical and technological properties of the coatings were investigated and the coatings were shown to be effective in application.