VOL 80, No. 7 (2007)

The influence of the coordination groups of boron, aluminum and silicon on the acid-base properties of the molten glass and the change in the redox state of copper in boron-containing melts has been studied. Indicators are proposed to assess the redox potential of the molten glass. They were used to compare the acid-base properties of industrial alkali-aluminoborosilicate glasses. Tab. 4, ill. 3, bibliography: 12 titles.

Equations are proposed for calculating the concentration of structural groups of constant composition (SCG) in borate glasses containing modifier oxides of the first and second groups of the periodic system. The partial molar volumes of the CGP were established and the molar volume of glasses of the indicated systems was calculated using the additive approximation formula. The calculated values ?? V _m satisfactorily approximate the experimental data of various authors - the maximum root-mean-square error of the calculation does not exceed 2.5%. Tab. 3, ill. 4, bibliography: 5 titles.

It has been shown that when molding ceramics by hot casting, volumetric changes in the slip in the hard-plastic state, amounting to 85% of total shrinkage, can be compensated for by plastic deformation of the casting. In this case, the completeness of the compensation for volumetric changes in the slip will be determined by the pressure gradient created in the casting during its solidification. Tab. 1, ill. 1, bibliography: 3 titles.

An unconventional method for determining the color of clay and ceramic materials in an air-dry and fired state in the coordinates of an equal-contrast color space using color characteristics (saturation, hue, yellowness, lightness, color coordinate) was used to classify clays of the Gzhel deposit and is recommended for adjusting the color gamut of ceramic products... Tab. 1, ill. 1, bibliography: 2 titles.

A model of polarization of a water molecule fixed on the surface of a solid by oxygen and hydrogen ions is considered. With an increase in the dielectric constant, the overlap voltage of solid dielectrics decreases. When designing insulators, one should take into account the nature of surface contamination (alkaline or acidic) in the places of use. Il. 2, bibliography: 6 titles.

The effect of the ratio of three alkaline oxides on the physicochemical properties of titanium-containing glass enamel has been investigated and their optimal concentrations have been determined. Developed acid-resistant enamel for steel cookware. Tab. 1, ill. 2, bibliography: 4 titles.

The features of the process of pressing and reaction sintering of compacts of cermet Al ₂ O ₃ - Al with the use of an additive of water glass have been studied. Its introduction in an amount from 3 to 28% by weight into the original aluminum powder, consisting of lamellar particles with surface alumina films, provides a granulate with a bulk density of 0.4 - 0.5 g / cm ³. Features of pressing granular powder were studied by analyzing logarithmic diagrams. It was found that the reaction sintering of samples in air occurs in the filtration combustion mode, and the dry residue of water glass activates sintering, providing the formation of nanodispersed inclusions & # 947; -Al ₂ O ₃ , & # 952; -Al ₂ O ₃, & # 945; -Na ₂ Si ₂ O < sub> 5 and Si in an aluminum matrix with a layered structure. With a cermet density of 2.40 - 2.45 g / cm ³, its flexural strength is 300 - 320 MPa. Il. 5, bibliography: 5 titles.

The ionic conductivity of the solid electrolyte La _2/3-x Li _3x TiO ₃ was measured in the temperature range 20 - 600 ° С with different isotopic compositions of lithium carriers current. It is shown that it has two components: low- and high-temperature, which differ greatly in the activation energy. The rates of spin-lattice relaxation of carriers have been measured by NMR on ⁷ Li nuclei. It was found that the activation energies of short-range and long-range carrier motion coincide in the temperature range of 20 - 500 ° C and differ sharply at higher temperatures. The influence of the concentration of cation vacancies on the motion of carriers of different isotopic composition is investigated. Tab. 2, ill. 4, bibliography: 7 titles.

The use of glasses of eutectic compositions in the CaO - P ₂ O ₅ system as a sintering additive and a source of a resorbable phase for obtaining a composite biomaterial for bone implants is considered. The use of such glass contributed not only to a decrease in the sintering temperature due to the implementation of the liquid-phase sintering mechanism, but also to the formation of a ceramic material with bioresorbability. The phase composition of the material obtained is represented by the phases of hydroxyapatite, vitlockite, and calcium pyrophosphate. Tab. 2, ill. 3, bibliography: 14 titles.