Vol 73, No 11-12 (2017)

The results of mathematical and experimental modeling of the process of cross cutting float glass during the output process by means of laser controlled thermal cleaving (LCT) are presented. The calculations and confirming experimental results show that efficient length and cross cutting of a ribbon of float glass is possible by using a CO₂ laser with power of the order of 500 W.

Phosphate glass with different Yb³⁺ concentrations was synthesized and studied. The composition of the glass made it possible to obtain optically uniform glass in small-volume crucibles. The basic spectral characteristics of the obtained glasses were determined and it was shown that the proposed matrix gives a high quantum yield of luminescence in a wide range of Yb³⁺ concentrations. The influence of the content of OH groups on the decay time of the Yb³⁺ luminescence was investigated. In view of its good cooking and casting properties this glass holds promise for use in the active media for near-IR solid-state and fiber lasers.

The processes involved in femtosecond laser modification of zinc-phosphate glass with a silver oxide ranging from 1 to 16 mol.% are studied and the optimal conditions for the formation of the luminescent microregions in the glass are determined.

Analysis of experimental data obtained by diffuse small-angle x-ray scattering (SAS) shows that even though it increases the total number of pores ranging in size from 10^–5 to 10^–4 m the wollastonite in ceramic face tiles secures the uniformity of the microstructure of ceramic materials.

The change in the Gibbs energy of reactions where SiC interacts with oxides of different nature in the temperature range from 298 to 2300 K is calculated and analyzed for the purpose of picking modifiers for obtaining structural ceramics from SiC. On the basis of the obtained data CaO, MgO, SrO, Al₂O₃, Y₂O₃, Sc₂O₃, and lanthanide oxides can be recommended for the synthesis of modifiers in energy-efficient silicon-carbide ceramic technologies.

This is devoted to the development of technology for forming the required microrelief of the optical surfaces of glass-ceramic substrates. It is shown that the problem can be solved by using controlled local deposition of silicon dioxide coatings on the surface by laser pyrolysis of tetraethoxysilane vapor in the presence of ozone. The characteristics of the experimental samples are presented and are compared with data obtained from mathematical modeling of the results of technological processes. It is shown that the developed technology can be used to profile substrates with large radii of curvature by successive deposition of multifilm coatings of interference spherical mirrors.

Bench tests of the abrasion resistance of hard and superhard inserts — carbide VK8, superhard composites based on cubic boron nitride PCBN, and polycrystalline diamond PDC—for new types of high-performance mining tools were conducted. Comparative tests in terms of fine-grained white granite with tensile strength 15 on M. M. Protod’yakonov’s scale and subsequent evaluation of the dependence of the wear spot area on the volume of removed rock showed that the abrasion resistance of PCBN inserts is 11.5 times greater and PDC inserts 80 times greater compared with VK8 carbide inserts.

The possibility of using PZT-19 ceramic in a pyroelectric x-ray generator is investigated experimentally. Measurements of the x-ray spectra showed the possibility of obtaining on a ceramic surface in vacuum potentials up to 7 kV, which is very low compared with typical similar values for pyroelectric crystals of lithium niobate and tantalate. This feature is due to the significant permittivity of the ceramic. It is shown that the main criterion for picking a ceramic for a pyroelectric x-ray generation could be the maximum value of the ratio of the pyroelectric constant to the permittivity.

The results of experimental research on the production of foam-glass-crystalline materials based on technogenic raw materials by a low-temperature technology for synthesis of granular glass are presented. The granular glass is an intermediate product of the formation of a glass body during heat-treatment of technogenic raw materials (slag, TPP fly-ash) and corrective additives. Subsequent foaming of the granular glass makes it possible to obtain a thermal insulation material — foam-glass-crystallite.