Vol 76, No 5-6 (2019)

A composite ceramic was obtained from granular silicon carbide dispersion-hardened with eutectic additives of the system Al₂O₃–MnO–TiO₂ was obtained. The influence of the dispersed powder of the eutectic in system Al₂O₃–MnO–TiO₂ on the sintering indicators of the ceramic matrix composite based on the granular silicon carbide was studied as a function of the silicon-carbide/eutectic-additive ratio 99/1, 97/3, and 95/5 and the pressing pressure. It was determined that after firing at 1350°C and pressing under pressure 200 MPa with introduction of 5% (weight content) eutectic additive with composition A or B the porosity is equal to 5.6 and 4.1%; the strength in bending reaches 65 ± 5 and 85 ± 5 MPa, respectively.

The possibility of synthesizing manganese-willemite ceramic pigments in the system xMnO · (2 – x)ZnO · SiO₂ (x = 0.125; 0.250; 0.375; 0.500; 0.625; 0.750; 0.875 and 1.00) was studied. Manganese-willemite ceramic pigments were synthesized at 800 – 1200°C. The obtained pigments were investigated by means of x-ray phase analysis, electron paramagnetic resonance, and infrared spectroscopy. A Tintometer RT 100 Lovibond reflective colorimeter was used to determine the color characteristics.

The results of studies of the physical and mechanical properties of glass fiber reinforced plastics [GFRP] modified by carbon nanotubes are reported. An epoxy binder was chosen as the polymer matrix; the glass fibers were macroscopic filler. Multilayer carbon nanotubes were used as the modifying additive. The mechanical properties of the polymer composites were analyzed as a function of the geometric parameters of the carbon nanotubes.

A high-efficiency laser-assisted method of removing tin-doped indium-oxide In₂O₃ (Sn) films from the surface of sodium-potassium-silicate glass used for railway-transport glazing. This method increases work productivity by a factor of 10 without degrading the strength of transport-engineering glazing and at the same time decreases environmental damage caused by the manufacturing process.

An improved design of a two-screw batch charger for glass furnaces is presented. It is noted that a change in the shape of the pushing shutter equipped with two trapezoidal side sections makes it possible to optimize by means of an additional pivot turn of the pusher arm around its axis the distribution of the batch over the molten-glass surface in a sealed doghouse.

The formation of very fine SiO₂ particles during milling of quartz glass in the fabrication of ceramic parts was investigated. A method for determining the quantitative content of very fine silica in slip based on quartz glass was developed and tested. The concentration of very fine SiO₂ particles in different batches of slip was determined. The influence of the content of the colloidal component in slurry on the sintering of ceramic material was evaluated.

Russian and foreign studies on the use of ash-slag wastes from thermal power plants (TPP) as raw material components in the production of foam glass and glass-ceramic foam materials are reviewed. It is shown that in a number of cases the use of waste improves the properties of the materials.

Native raw materials — ferriferous diatomites from the Zhalpak deposit in Kazakhstan — are proposed for use as an accessible, cheap, raw material for obtaining complex iron-oxide silica-containing pigments. Pigments with color gamma were obtained. Electron microscopy, BET analysis, Mossbauer spectroscopy, and x-ray phase spectroscopy were used to determine the mineralogical composition, shape, size, specific surface area, and total pore volume of the particles. Scanning electron microscopy showed that the diatomite particles acquire a spherical shape and size 5 – 10 μm as a result of thermal activation and mechanical action.

Statistical quality control of laminated windshields during bending was performed. Parameter deviations of the articles from technical specifications were uncovered. A logistic regression model was constructed to determine the probability of obtaining high-quality laminated automobile glass as a function of the bending regime. It was shown that logistic regression is effective for on-line inspection of laminated windshields and in making decisions concerning bending regime adjustments.

Glass-ceramic based on compositions in the system Sr(Ba)–Al₂O₃–SiO₂, modified by additions of zirconium oxide ZrO₂ and hafnium oxide HfO₂ with and without yttrium as a stabilizer, was synthesized by the sol-gel method. It was shown that the introduction of refractory oxides shortens the gelation time of the initial solutions, intensifies the sintering of the glass-ceramic, and changes the temperature intervals of phase formation processes and the nature of the precipitated crystalline phases. The sol-gel method made it possible to obtain a uniform distribution of the modifier-oxide grains in the bulk of the glass-ceramic. The yttrium oxide in the structure of the materials is concentrated near ZrO₂ and HfO₂ particles.

Samples of electrodes with an active layer based on TiO₂, RuO₂ , IrO₂ , and oxides of the rare-earth elements Ce, La, Nd, Pr, Gd, and others were obtained, and their electrochemical behavior was studied. The zero-current potential was determined. The rates of the anionic chlorine and oxygen evolution processes and the impact of the heat-treatment temperature of the final layer on the electrochemical characteristics are presented as functions of the composition of the electrode.

The activity of foam ceramic and foam glass in terms of the silicate-alkali interaction in concrete was investigated. It was found that in the wet environment in concrete the vitrified walls of the pores of the aggregates are chemically active. The transformations of foam ceramic include gelation of the pore walls with formation of an alkaline aluminosilicate gel followed by its crystallization. This binds the active components on such an aggregate in the crystalline phases, which are inert in a moist environment. The final stage of the transformation of the foam glass is noncrystallizing, alkaline, hydrated, silica gel.