Vol 74, No 3-4 (2017)

The results of a successful application of laser-controlled thermo-splitting (LCT) for precision cutting of glass, ceramic, and other brittle nonmetallic materials are presented. Other forms of the LCT method are examined: laser de-faceting, laser parallel thermo-splitting, and application of optical grids and rulings.

It is proposed that the conditioning of molten glass in the feeder channel of a glass furnace be conducted on the surface of melted copper. It is shown that this will make it possible to decrease the thickness of the layer of molten glass, increase the thermal uniformity of the layer, decrease the fluctuations of the level of the molten glass, and increase product quality. Questions concerning the interaction of the melted copper with the molten glass and the feeder-channel atmosphere are examined.

The conditions for obtaining and the rules for changing the color indices of ceramic pigments in the system CaO–MgO–Al₂O₃–SiO₂–Cr₂O₃ are established. The main phase of such pigments is chromium garnet, formed with the direct participation of blast-furnace slag minerals. It is shown that as the acidity of pigment batches is increased by equimolecular substitution of free silicon dioxide in their composition based on phosphorus oxide (V) the purity and intensity of the green color of uvarovite pigments intensifies and the firing temperature of the pigments increases to 1100 – 1150°C.

The effect of a number of additives on the rheological properties of clay was investigated. The change in the maximum dynamic shear stress and plastic viscosity as a function of the concentration of complex additives was examined. It is shown that technical-grade lignosulfonate can be used as one of the components of a complex thinning additive for clays. It is found that lignosulfonate used in combination with sodium tripolyphosphates improves the casting characteristics of the ceramic body.

Spark plasma sintering (SPS) was used to obtain a fine-grain (of the order of 200 nm), dense, strong ceramic (microhardness to 10 GPa) on the basis of nanosize cobalt oxide powder.

The chemical-mineralogical composition of local leucocratic granites from the Kargaliiskoe ore deposit was studied. Petrographic and scanning electron microscopic analyses were used to investigate the microstructure. Leucocratic granite consists mainly of the minerals microcline, albite, and quartz; it is a valuable nonmetalliferous ceramic raw material, which can replace imported deficit feldspar materials use in ceramic bodies.

A scaled-down prototype of a die for extruding ceramic brick with ultrasonic oscillations from a magneto-striction transducer delivered onto the die wall was tested. Extruder productivity was increased. There is a complex improving effect on the microstructure of the ceramic, drying properties, shrinkage, water absorption, and density and strength, making it possible to reduce the plasticity requirements of clay. The test result shows that it is possible to develop an ultrasonic die for industrial extruders.

The kinetics of pore formation in pressed parts of the system cullet – clay – colemanite, fired with different rates of heating, was investigated. It was found that the measured heating rates (2.5 – 3 K/min) bring the processes occurring during firing closer to equilibrium and make it possible even at 680°C to obtain glass ceramic materials with uniform fine porous structure and satisfactory properties and to preserve the shape of the parts.

The result of development work on the composition of batch and matching the firing temperature for the production of glass ceramic material for purposes of obtaining matched junctions with molybdenum owing to close values of the CLTE are presented. Validation is given for using cullet comprised of window sheet glass as a binder in amount 30% and firing at temperature 1000°C.

The results of a determination of the granulometric composition of lithoidal clayey raw material with different degrees of lithifaction — argillaceous clays, argillites, clayey shales — by means of laser diffractometry are presented. The particulars of the granulometric composition of these rocks as well as the effect of their dispersion duration and intensity are determined. It is shown that laser diffractometry can be used to evaluate the quality of raw materials of this type for the production of different types of ceramic articles.

A hybrid electrochemical storage cell is suggested as an energy storage unit in autonomous photovoltaic systems. The developed setup combines the advantages of lithium-ion batteries and bilayer capacitors. The increase in energy capacity is achieved by increasing the mass ratio of the positive and negative electrodes.

Protective coatings on the inner surfaces of discharge envelopes of radiation sources contain oxides of aluminum, yttrium, magnesium, zirconium, and thorium. Protective coatings make it possible to increase the inertness of glass burners on the inner surface of discharge envelopes with respect to vapors of corrosive metals at high temperatures and pressures as well as to increase several-fold the service life of mercury-cesium lamps with very small reduction of radiation during operation within the bounds of their required service life.