VOL 81, No. 6 (2008)

A review of works on the study of the properties and characteristics of glasses, which determine the operational reliability of the most common glasses and glassware, is presented. The theoretical provisions, general issues of strength, chemical resistance (corrosion) and spectral characteristics of glasses are noted. The specified properties and characteristics are considered in relation to sheet glass, glass fiber and glass containers. Tab. 3, ill. 5, bibliography: 24 titles.

It was found that during low-temperature processing ( g) of multicomponent glass with additions of phosphorus oxide in the glass powder, crystallization proceeds, accompanied by the release of calcium silicophosphate, which was not previously described in the literature. The resulting compound has a cubic system, space group P _P ³ unit cell parameter a = 7.98 & Aring ;. Tab. 3, bibliography: 5 titles.

The influence of the degree of aggregation of powders, properties of aggregates (size, strength, porosity) on the degree of sintering and characteristics of the microstructure of the manufactured ceramics is shown. The conditions for obtaining powders with a low degree of aggregation, as well as methods of powder disaggregation, are considered. Requirements for powders that provide the same pore size in compacts and a uniform degree of sintering throughout the volume of products are formulated. Tab. 2, ill. 2, bibliography: 9 titles.

Polycrystalline samples of zirconia stabilized with 10% Y ₂ O ₃ (molar content) with additions of Li ₂ O up to 3% were synthesized by the solid-phase method. It was found that the conductivity of the samples significantly increases with the introduction of Li ₂ O and reaches a maximum at an additive content of 1.7%. The activation energy of conduction decreases from 0.85 eV in samples without additions of Li ₂ O to 0.56 eV in samples containing 1.7% Li ₂ O. It is assumed that lithium ions in the lattice of cubic ZrO ₂ form two types of defects: substitutional defects - Li _Zr ^3- and interstitial defects - Li _i ⁺. The latter significantly increase the electrical conductivity of the samples. Il. 3, bibliography: 14 titles.

The main regularities of the color formation of porcelain containing neodymium oxide, which has the ability to change color depending on the light source using absorption and reflection spectra, have been studied. In the metric system CIE 1976, the optimal content of neodymium oxide in porcelain was determined, the dependence of the color of products on the firing environment and the light source was established. Tab. 3, ill. 6, bibliography: 9 titles.

It has been shown that the K ₂ O - Al ₂ O ₃ - SiO ₂ system is promising for the production of glass ceramics containing leucite and intended for the manufacture of dentures. Glass formation in this system and the crystallization ability of glasses, including those modified with Li ₂ O and Na ₂ O, have been studied. The influence of temperature-time parameters on liquation and crystallization processes has been studied. Tab. 1, ill. 3, bibliography: 2 titles.

The study of the influence of the composition of calcium silicate glasses on the behavior of powders of different dispersion (500, 60 and 10 microns) in an aqueous medium has been carried out. The acid-base characteristics of the aqueous medium and the concentration of calcium ions in the aqueous solution after holding the glass powders have been determined. It is shown that the main parameter determining the mechanism of glass dissolution in water is their basicity modulus. Tab. 2, ill. 2, bibliography: 4 titles.

A technique for constructing and applying models on artificial neural networks for analyzing and regulating the mode of forming a glass ribbon on a tin melt is considered. The technique provides for the creation of models on neural networks describing the dependence of the glass property indicators on the regime and controlled input variables, as well as the development of an algorithm for adjusting the regime variables depending on the thickness of the glass strip produced, taking into account changes in controlled disturbances. Tab. 3, ill. 1, bibliography: 3 titles.