Vol 73, No 3-4 (2016)

The possibility of eliminating the alkali-silica reaction (ASR-interaction) in foam glass owing to crystallization of glass is examined. It is found that the main crystalline phases in the crystallization of the amorphous phase of foam glass are devitrite (Na₂Ca₃Si₆O₁₆), an octahedral phase (Na₄CaSi₃O₉), and a cristobalitetridimite modification of SiO₂. The binary glass ceramic composition of foam material shows significant ASR-interaction diminishment. The tile foam-glass-crystallite (Penosital®) can be glued or plastered with a cement-sand solution and covered with finishing polymer stuccos. The granular foam glass-ceramic can be successfully added as light aggregate to concrete without it disintegrating.

The results of research on the resistance of basalt fibers with different chemical and mineralogical compositions to corrosive media are presented. It is shown that they have high chemical resistance to water, acids, and alkali. Aparameter is proposed for predicting the chemical resistance of fibers as a function of their content of metal oxides in glass. The method of determining the change in strength of fibers after they are treated in corrosive media gives the most reliable results.

An energy-conserving technology for shrink-free face materials is proposed and tested. It is based on the superposition and cancellation of two opposing deformation effects in the sintering process: volumetric shrinkage and foaming with formation of a microporous structure. The necessary conditions for implementing the proposed technology are indicated.

Luminescent materials, activated by europium ions, with the composition SrAl₂Si₂O₈/LaBO₃ were synthesized using organosilicon compounds (methyl polysiloxane MK). The luminescence properties in red and blue LED range are characteristic of materials synthesized at 1100°C. In addition, strong luminescence is characteristic of trivalent europium ions (peaks at 591, 616, and 655 nm) in the red region of the spectrum and weak luminescence in the blue region of bivalent europium ions (peak at 405 nm). The possibility of incorporating two types of europium cations (Eu²⁺ and Eu³⁺) into the structure of synthesized polycrystalline materials makes it possible to regulate their spectral properties as a function of the conditions of synthesis.

The porous structure of polymer and gypsum molds is analyzed. Models of their structure based on models of randomly arranged spheres and percolation theory are proposed. The computational expressions for evaluating the parameters of a porous structure are refined and the structural parameters obtained for polymer and gypsum molds are presented. The computational results are presented.

Phase formation is studied in the system BaCO₃ + TiO₂ by means of solid-phase reactions and synthesis from melt obtained by the action of concentrated solar radiation of different intensities. It is shown that barium metatitanate BaTiO₃ in the cubic system forms at intensities up to 100 W/cm². As the radiation intensity increases, a tetragonal phase of barium titanate forms. The barium titanates obtained have high permittivity (3000 – 3200) and low dielectric losses.

The efficacy of titanium dioxide as an opacifier for glass ceramic, wear-resistant, semi-fritted, glaze coatings with the required physical, chemical, and operating characteristics for floor tiles is determined. Infrared spectroscopy, x-ray phase analysis, and electron microscopy are used to perform a comprehensive study of the formation of composition-optimized glaze coatings.

The results of work on the development of a batch composition for the production of ceramic brick based on local low-quality clay with addition of galvanic sludge from a local enterprise and modifying additives are presented. The results of a determination of the basic physical-mechanical properties of the material obtained are presented.

A new method is proposed for synthesizing yttrium-aluminum garnet Y₃Al₅O₁₂ powder. The method consists in anion exchange coprecipitation of yttrium and aluminum from chloride solutions by the anionite Purolite A-300 in the OH-form and calcination at 900 °C of the precursor formed. The product was investigated by means of XPA, DSC, IR-spectroscopy, and electron microscopy. The Y₃Al₅O₁₂ particle size was 300 nm.

The fabrication particularities of optically transparent ceramic materials for different applications are examined. The technologies used for compacting and sintering transparent ceramics are described: cold pressing followed by sintering in different media, hot pressing, hot isostatic pressing, spark plasma sintering, and slip casting.

The conditions for the synthesis of zircon crystals from a fluxed solution are studied. It is proposed that CaCl₂ be used as flux. Samples of luminescent zircon are obtained with activation by Dy³⁺ and Eu³⁺ ions. The luminescence properties of the materials obtained are investigated and the luminescence spectra of pure zircon (synthesized using Li₂MoO₄ and CaCl₂ as fluxes) are compared with those of activated zircons and standard YAG luminophore. The activated zircon obtained can be used as radiation converters, for example, as a red luminophore in illumination devices.