VOL 77, No. 6 (2004)

A method is proposed for obtaining a chemically homogeneous glass batch by introducing fine and hygroscopic raw materials in the form of microgranules into its composition, followed by compaction of the batch. Glass batch prepared by this method has high homogeneity and chemical activity. Bibliography: 1 titles.

The results of the analysis of systems and areas of application of low-melting glasses based on the literature data used to select the optimal system are presented. The melting properties of low-melting glasses based on the borate system ZnO - SrO - B ₂ O ₃ have been studied. The dependences of the main properties of glasses on the composition (TLEC, temperature of the onset of softening, microhardness, chemical resistance to water) have been established. The optimal compositions of low-melting glasses with the required physicochemical and technological parameters have been determined. Il. 3, bibliography: 7 titles.

The characteristics of microporous borosilicate glasses are presented. Recommended for the production and use of glass with an optimal pore distribution. Tab. 2, ill. 3, bibliography: 2 titles.

To study structural transformations during crystallization and to quantitatively determine the content of phases after different modes of heat treatment and irradiation, a standard-free X-ray method of qualitative phase analysis has been proposed. Tab. 1, ill. 2, bibliography: 6 titles.

The microstructure of material samples based on natural wollastonite was investigated at various sintering temperatures (850 - 1100 ° C). The influence of microstructure on porosity, shrinkage, water absorption and mechanical strength is shown. The essence of physical and chemical processes is explained. Physical and mechanical characteristics of the material are given. Tab. 1, ill. 2, bibliography: 7 titles.

A comparative analysis of the machining of ceramic materials based on aluminum oxide, silicon nitride and carbide has been carried out. Recommendations are formulated for choosing the type of grinding wheel, grinding speed and pressure exerted by the wheel on the workpiece. Tab. 2, ill. 3.

The issues of using flue emissions from thermal power plants - hollow ceramic microspheres - in syntactic materials with increased dielectric characteristics are considered. Comparative dielectric properties of the obtained materials and materials based on hollow glass microspheres are presented. Tab. 1, ill. 1, bibliography: 3 titles.

The thermal expansion of mullite-cordierite, mullite and quartz ceramics, which was used to obtain materials with protective coatings from Nb ₂ O ₅, has been investigated. It is shown that, in terms of the nature of thermal expansion, the closest to Nb ₂ O ₅ are fused quartz glass and quartz ceramics in the absence of cristobalite phase in it. Variable composition alloys (Nb ₂ O ₅) _x - (SiO ₂) _{1- x < / sub> have intermediate TCLE and can be used to compensate for the stress mismatch between the coating and the quartz ceramic substrate. Il. 5, bibliography: 6 titles.}

An overview of low-melting borosilicate glasses and glazes for majolica and pottery is presented. The given data on the compositions and properties of glasses allow us to dwell on a specific composition with the required properties and refer to the original patent source. Tab. 1, bibliography: 3 titles.

Low-melting enamel coatings for household utensils from aluminum have been synthesized. The possibility of the formation of fusible glasses in the R ₂ O-Al ₂ O ₃ - B ₂ O _{system has been investigated 3} - TiO ₂ - P ₂ O ₅. The optimal composition of the glass matrix with a reduced firing temperature of 580 ° C has been selected. Tab. 1, ill. 2, bibliography: 3 titles.

The kinetic features of the oxidation of alloy steel under a coating layer containing iron oxide are considered. The dependence of the oxidation rate of steel on the concentration of Fe ₂ O ₃ in the melt has been experimentally established. Il. 2, bibliography: 6 titles.

The possibility of using quartz-feldspar rocks of Karelia for the production of electrical ceramics is shown. It was found that cakes of alkaline syenites are distinguished by low dielectric losses (0.25) and dielectric constant equal to 6.5. Volcanogenic rocks - quartz porphyry with a high content of quartz and microcline - reduce the dielectric constant of the cakes to 5.4, and the potassium gelleflint has a dielectric constant similar to that of pegmatites - 7.7. Tab. 1, ill. 2, bibliography: 4 titles.