Volume 74, Nº 1-2 (2017)

A new laser-blunting technology using thermal stresses to remove the sharp edges of articles made of glass and other brittle nonmetallic materials is described. A physical model is proposed for laser heating of the edges of a metallic material that is opaque to laser radiation. A relation is established between the main parameters of the process: facet size, defaceting speed, laser radiation intensity, and glass edge strength. The technological regimes are optimized; the technological process and laser equipment for cutting and defaceting glass are elaborated. The advantages of the new technology of laser blunting of glass edges over the conventional defaceting technology using a diamond-abrasive tool are shown.

Glasses in the silicate, borosilicate, aluminum-silicate, and aluminum-boron-silicate systems are studied. Expressions are obtained for determining the activation energy of hydrogen permeability and the hydrogen permeation rate as a function of the content of all, without exception, components present in the experimental glasses and for comparing glasses of different compositions in terms of permeability and permeability of glasses upon heating. The ranges of these criteria are determined. It is shown that silicate glasses impermeable for hydrogen do not exist.

Amathematical model based on fuzzy sets that describes the dependence of the residual stresses in sheet glass on the annealing regime is developed. An adaptive system for controlling the annealing of the glass by using a model describing the dependence of the residual stresses on the annealing regime is proposed. Simulation modeling is used to show that the residual stresses in the produced glass can be stabilized using the operating equipment by automating the control of the technological process of annealing.

The luminescence spectra in samples of fired kaolin are investigated. It is shown that the obtained radiation corresponds to the luminescence of Cr³⁺ ions in mullite. The effect of the firing temperature and mass content of chromium oxide on the emission spectra is studied. The activation energy of mullite formation is determined from the experimental dependences to be E_a = 144 ± 6 kJ/mole and the maximum solubility of Cr₂O₃ in mullite equals 0.33%.

The results of microstructure investigations of clinker ceramic with different chemical composition are presented. Data are systematized. An explanation is proposed for the formation of the phase composition of ceramic in association with the particulars of the technological process of the production and properties of parts. The obtained data significantly facilitate the process of formulating the batch, predicting the properties of parts, picking heat-treatment regimes, and decreasing the number of rejects, and in additions picking decorative coatings.

The conditions for the formation of phases with different technological prehistory in the system Cu–Cr–O are analyzed. The synthesized materials are characterized by means of x-ray phase analysis. The conditions for obtaining samples of CuCr₂O₄ with the maximum amount of spinel, which include a soft temperature regime and a single step, are discussed.

Iron-containing catalytic systems based on nanoporous aluminum silicates obtained by the sol-gel method have shown high activity and stability in the oxidative destruction reaction of azo dye by hydrogen peroxide in water solutions and can be recommended for rendering waste waters containing organic dyes as impurities safe.

The influence of the surface properties of the developed calcium-silicon-phosphate glass ceramic materials and coatings on biocompatibility is determined. The calcium to phosphorus ratio on the surface of materials and coatings for forming an apatite-like layer on them as well as the optimal values of the roughness parameter and free surface energy for adsorption of protein molecules and adhesion of osteogenic cells are determined.

The physical-chemical processes involved in the formation of the cellular structure of heat-insulation building glass materials as a result of thermoplastic sintering of batch at temperatures 600 – 870°C are examined. Such a cellular glass formation process occurs because the significant gas-phase volume formed at low viscosity diffuses in the thermoplastic ceramic mass and in so doing creates the pore structure of the cellular heat-insulation glass.

The effect of the surface preparation method used on aluminum oxide ceramic on the structure and properties of a deposited metallic coating was studied. Surface preparation stages such as degreasing, etching, sensitization, and activation have made it possible to obtain uniform metallic coatings with strong adhesion. The sensitization and activation stages can be combined into a single stage of direct activation.

The chemical and mineralogical compositions, physical and chemical characteristics, and degree of metamorphosis of quartz mineral in high-silica rocks in the Dzherdanakskoe deposit were investigated. It was found that this deposit contains shales and sandstones together with quartzites. It is shown that these high-silica raw components hold promise for the development of compositions of ceramic and refractory materials.