VOL 90, No. 12 (2017)

The local crystallization of barium-titanosilicate glass under the action of a femtosecond laser beam is investigated. The effect of the laser beam scanning speed and laser pulse energy on the morphology of channels containing Ba ₂ TiSi ₂ O ₈ fresnoite crystals is determined. The preferential orientation of fresnoite crystals in the formed channels has been established by the method of polarization Raman spectroscopy. The results obtained open up prospects for the development and manufacture of waveguide crystal structures with low optical losses for photonics and integrated optics.

The results of the synthesis of antireflection mesoporous coatings based on silicon dioxide obtained by acid hydrolysis of tetraethoxysilane (TEOS) in the presence of organic additives are presented. Investigations of the influence of the acidity of the medium, the nature and mass content of the modifier on the optical properties of the coated glass have been carried out. Optimal synthesis parameters have been determined

A selective quality control of the produced multilayer windshields during their bending was carried out. Deviations of the magnitude of surface tensile stresses in the edge of the glass from the requirements of technical conditions are revealed. Adaptive models are compiled that describe the dependence of the tensile stress in the edge of the glass on the temperature regime of bending. An algorithm for controlling the temperature regime of bending has been developed. Simulation modeling has shown the possibility of stabilizing the magnitude of surface tensile stresses in manufactured products.

Experimental results of the synthesis of diamond-like high-pressure compounds using the high-pressure technique and the method of laser deposition are presented. Their combination of unique characteristics can be achieved by varying the B / C ratio. The possibility of spraying micron or nanosized carbon films with a high boron content opens the way to the use of such materials on an industrial scale. Hetero-diamonds with a high boron content have high elastic moduli, and diamond polycrystals doped with boron have metallic conductivity.

During solid-phase synthesis of piezoceramic materials based on complex oxides with a perovskite structure, anomalous thermal expansion of the pressed mixture of the initial reaction components is observed. Under certain conditions, the magnitude of this expansion can be an indicator of the degree of progress of solid-phase reactions. The analysis of the thermal expansion of a compressed mixture of powders of potassium, sodium and niobium carbonates during the synthesis of complex oxide of potassium and sodium niobate KNN is carried out. It is shown that on the basis of this analysis it is possible to estimate the temperature and completeness of the synthesis reaction. Several schemes for the solid-phase synthesis of this material are considered. From the material obtained, samples of piezoceramics with a density of up to 92 & # 37; from theoretical and value of piezomodulus d ₃₃ to 1.010 ^-10 C / N

An original technique has been developed for controlling the strength characteristics of porous ceramic compositions of the abrasive grain - bond - pore system in order to obtain a composite that ensures maximum performance of the grinding tool made from it. The experimental and mathematical dependences of these characteristics, which form the basis of the methodology proposed by the authors, are given. An example of its implementation in the manufacture and operation of the tool is given.

The processes occurring at the stages of mechanical activation of powders and firing of samples pressed from calcium phosphate nanopowders with a molar ratio of Ca / P = 1.25 have been studied. Washing the nanopowder in distilled water and alcohol after mechanical activation led to the removal of ammonium phosphates, and only hydroxyapatite and tricalcium phosphate were present in the ceramics. To preserve the molar ratio Ca / P = 1.25 in the ceramics, washing should not be carried out, then after firing, in addition to the indicated phases, calcium pyrophosphate is also present in the ceramics.

The properties of ceramics in the case of clay modification with a small addition of glass fiber during ultrasonic extrusion of laboratory specimens have been investigated. Ultrasound enhances the hardening effect of the modifier. It compresses the charge and orients its elongated particles along the direction of extrusion. After firing, the modifier particles turn into hollow geode nodules with a polycrystalline anorthite shell, filled with needle crystals. The proposed extrusion technique increases the accuracy and information content of testing modified clays.

High-temperature enamel coatings with a sufficiently high firing temperature have been obtained, which provide the necessary protective properties and heat resistance. The results of scientific and experimental studies of the parameters and properties of the obtained coatings based on composite compositions modified by the addition of refractory fillers introduced by nanosized oxide powders are presented.