VOL 96, No. 1 (2023)

The effect of femtosecond laser micro-treatment in thermal and non-thermal modes on the structure of transparent glass-ceramic based on the ZnO–MgO–Al2O3–SiO2 system, characterized by increased mechanical strength and hardness, is investigated. The amorphization of nanoscale ganite (ZnAl2O4) crystals, which occurs under the irradiation of laser pulses, is confirmed by the results of electron microscopy and electron diffraction. Quantitative phase microscopy was used to evaluate changes in the refractive index in individual tracks written by a laser beam. At the repetition frequency of 10 kHz in non-thermal mode, complete amorphization of the crystal phases in volume glass-ceramic sample leads to an increase of the refractive index by the value ?n = 0.0007 in the laser processing area. The results obtained expand the potential applications of transparent glass-ceramics with increased mechanical properties and open up the possibility of forming channel waveguides in their volume by direct laserwriting.

Gel casting is one of the new and promising methods for producing ceramics. Modern research on the production of ceramic materials by gel casting covers a wide range of materials, including both dense and porous ceramic materials.
The advantages of this method, such as ease of processing, the use of technological equipment of traditional methods, increased productivity, the possibility of obtaining products of large shapes and complex geometry, gave impetus to new research and development. This article provides an overview of publications devoted to research in recent decades on the production by gel casting of both dense ceramics for the manufacture of structural elements and porous ceramics for the manufacture of thermal insulation, porous filters and membranes.

The results of studying the influence of the chemical composition, material structure, crystallization features and isomorphic substitutions in pyroxene solid solutions of the augite type on the mechanical characteristics of glass ceramics are presented. The mechanism of structure formation is shown, which consists in the crystallization of chromium spinel and subsequent growth on its surface of crystals of a pyroxene solid solution of the augite type in the form of spherical intergrowths, which ensures high mechanical strength of glass-ceramic proppants. It has been established that during the course of isomorphic substitutions in the diopside-augite series, the mechanical strength of glass-ceramic proppants increases, which is associated with a decrease in bond lengths, an increase in their number, and compaction of the unit cell.

The paper analyses the effect of dolomite powder on properties and durability of clay brick. Clay bricks were made from the mix containing from 10 to 30 % of waste dolomite powder and fired at 1000 ?C temperatures. In this case, clay bricks density is 1.55 – 1.75 g/m3, compressive strength 14 – 28 MPa, water absorption 15.3 – 19.7 %, total porosity 31,0 – 40.4 %, durability (resistance to freezing and thawing) not less than 25 cycles.

Luminescent films were obtained by the capillary method on the basis of inorganic, organometallic, and hybrid organic-inorganic powder materials. The films were deposited on surfaces of various nature and roughness and exposed to the tropical climate of Southeast Asia throughout the year. The hybrid films showed high stability, comparable to commercial inorganic phosphors.

The chemical-mineralogical compositions, new formations of crystalline phases of minerals and the main properties of the ceramic mass were studied using iron-containing dust from the gas cleaning of steel-smelting furnaces of metallurgical production during sintering in the temperature range of 950 – 1100 ?C. It has been established that with the introduction of gas cleaning dust, the structure is stabilized and the sintering temperature of the ceramic shard is reduced.

The article provides a brief historical outline of the activities of the Technology of Silicates and Nanomaterials Department of the National Research Tomsk Polytechnic University which is the first technical university in the Asian part of Russia. Initially, the Laboratory of Chemical Technology of Mineral Substances, since 1929 the Silicate Technology Department, since 2007 the Technology of Silicates and Nanomaterials Department, nowdays it is one of the leading scientific and educational centers of the country for the study of silicate raw materials, the development of advanced technologies for ceramics, binders and glass materials, and the training of engineers and scientists specializing in the relevant fields.
Research areas of the team embrases now the development of materials and technologies for nanostructured technical and building ceramics with enhanced functional properties, foam glass-ceramic materials, proppants for oil and gas production, biomedical ceramics, magnesian binders with increased strength and water resistance.

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