Vol 74, No 11-12 (2018)

Random inspection quality control of laminated windshields during sag molding was performed. The deviations from the technical specifications of the surface tensile stresses at the edge of the glass were revealed. Adaptive models describing the dependence of the tensile stresses at the glass edge on the sag bending temperature were constructed. An algorithm was developed for controlling the sag bending temperature. It is shown by means of simulation modeling that the magnitude of the surface tensile stresses in the produced articles can be stabilized.

A novel method of controlling the strength characteristics of porous ceramic composites in the system abrasive grain – binder – pores so as to obtain a composite maximizing the serviceability of grinding tools fabricated from the ceramic was developed. The experimental and mathematical dependences of these characteristics, which comprise the basis of the method proposed herein, are presented. An example of the implementation of the method in tool fabrication and operation is given.

The particulars of mechanochemical interaction in the system Ca(OH)₂–Al–H₂O were studied by means of x-ray phase, x-ray structural, and simultaneous thermal analyses. It is shown that the combined mechanical activation of the initial components in the ratio of Ca(OH)₂: Al = 1 : 2, 1 : 4, 1 : 12 and subsequent heat treatment at 1000°C leads to the formation of aluminates with the same molar ratio. Studies of the specific surface area and mechanical strength of the synthesized samples established that calcium hexaaluminate has the highest indices.

The results of synthesis of anti-reflective, mesoporous, silicon dioxide based coatings obtained by acidic hydrolysis of tetra-ethoxy-silane (TEOS) in the presence of organic additives are presented. The effects of the acidity of the medium and the nature and mass content of the modifier on the optical properties of coated glass were investigated. The optimal parameters of synthesis were determined.

Experimental results from the synthesis of diamond-like BC_x compounds with the aid of high-pressure techniques and laser sputtering methods are presented. A combination of unique characteristics in these compounds can be attained by varying the B/C ratio. The possibility of sputtering carbon films of micron or nanosize thickness with high boron content opens up a way to use such materials on industrial scales. Hetero-diamonds with high boron content have high elastic moduli and boron-doped diamond polycrystals possess metallic conductivity.

The properties of ceramic are studied in the case where clay is modified by adding small amounts of glass fiber in the process of ultrasonic extrusion of laboratory samples. Ultrasound increases the strengthening action of the modifier. It consolidates the batch and orients its elongated particles along the direction of extrusion. After firing the modifier particles become hollow concretions-geodes which have a polycrystalline shell comprised of anorthite and are filled with needle-shaped crystals. The proposed method of extrusion increases the accuracy and informativeness of tests performed on modified clays.

High temperature enamel coatings with quite high firing temperature, which impart the required protective properties and heat resistance, were obtained. The results of scientific and experimental studies of the parameters and properties of the obtained coatings based on composite make-up modified by additives of refractory fillers introduced by via nanosize oxide powders are presented.

The processes occurring during the mechanoactivation of powders and firing of samples pressed from calcium phosphate nanopowders with molar ratio Ca/P = 1.25 were studied. As a result of washing nanopowder in distilled water and alcohol after mechanoactivation ammonium phosphates were removed and only hydroxyapatite and tricalcium phosphate were present in the ceramic. To preserve the molar ratio Ca/P = 1.25 in the ceramic washing should not be performed, and then after firing, aside from the indicated phases, calcium pyrophosphate is also present in the ceramic.

Comparative tests were performed of a vertical-type centrifugal mill for milling wastes from the production of ceramic articles: insulators and crushed mullite brick. It is shown that the use of a vertical centrifugal mill in the comminution of wastes from the production of ceramic articles increases the efficiency of waste processing.

The results of an experimental study of x-ray generation aided by a ceramic piezoelectric transformer placed in vacuum are presented. X-rays were emitted with the piezoelectric transformer tuned to resonance at about 20 kHz. A characteristic emission peak of a titanium target at energy of 4.5 keV against the Bremsstrahlung background was observed in the measured x-ray spectra. The maximum energy of the x-ray Bremsstrahlung reaches 12 keV. This means that the electrons are accelerated in vacuum in the field of the piezoelectric transformer to at least 12 keV.

Local crystallization of barium titanate silicate glass under the action of femtosecond laser beam was studied. The effect of the scan rate of the laser beam and the energy of the laser pulses on the morphology of the channels containing crystals of fresnoite Ba₂TiSi₂O₈ was determined. Polarization Raman scattering spectroscopy was used to determine the predominant orientation of fresnoite crystals with formed channels. The results open up prospects for developing and fabricating waveguide crystal structures with low optical losses for photonics and integrated optics.