VOL 73, No. 5 (2000)

It is proposed to introduce the concept of stability of the thermal regime of molds for pressing glass products and a formula for calculating the stability coefficient, which will allow simulating the conditions of their production, taking into account changes in the temperature of the external environment and the duration of pressing. Il. 1, bibliography: 7 titles.

The nature of the concentration dependence of the molar volume of three-component aluminosilicate glasses, in which the content of R ₂ O (or RO) exceeds the content of Al ₂ O ₃, is determined by the degree of depolymerization structural glass mesh. In glasses with an equimolar content of R ₂ O (or RO) and Al ₂ O ₃, the molar volume is additive and depends on the partial values ??of the molar volume of "silica "and" aluminate "constituents of the structural grid. Tab. 2, ill. 4, bibliography: 12 titles.

The physicochemical features of the processes of drying bulk silica gels formed from mixed sols - tetraethylorthosilicate hydrolyzate: aerosil - are considered. The results of experimental studies of the kinetic curves of drying bulk-molded silica gels depending on the conditions and modes of the processes are presented. Il. 7, bibliography: 8 titles.

A method of strengthening parts of molded equipment by boriding is considered, the regularities of changing the dimensions of parts during boriding are given, the issues of mechanical processing of borated parts and the peculiarities of using diamond and other pastes and powders are highlighted. Bibliography: 4 titles.

It is shown that the connectivity and plastic strength of wet materials, their thermophysical and drying properties are predetermined by the ratio of the capillary-mobile and capillary-immobile forms of moisture and the natural properties of materials, the complex of which should be evaluated by the lowest capillary or maximum molecular moisture capacity, which are the most important water-physical characteristics of materials.... Formulas are proposed for calculating the dependence of the connectivity and plastic strength of materials on moisture content, their sensitivity to drying, as well as formulas for calculating the thermophysical properties of wet materials. Il. 5, bibliography: 10 titles.

A technology has been developed for glazing wall ceramics by preliminary flashing of dried unfired products with a plasma torch with their subsequent firing. Tab. 1, bibliography: 9 titles.

A comprehensive physicochemical study of hydroxylapatite obtained by the wet method was carried out. The possibility of using the material both in bioceramics and in catalytic and sorption processes as a catalyst and sorbent is shown. Tab. 1, ill. 2, bibliography: 3 titles.

The sol-gel method was used to obtain composite ceramic materials based on a siloxane binder and fine powders of refractory fillers (based on various borides, nitrides and carbides), which do not require prolonged sintering at high temperatures. It was found that the best filler is AlN - after heat treatment at 900 ° C, the material based on it has increased hardness, strength, and heat resistance. Tab. 1, bibliography: 6 titles.

The results of studies of clay minerals of the Malo-Budishchanskiy deposit (Poltava region) used for the production of facing bricks are presented. It is shown that the introduction of kaolinite-hydromica clays into the composition of the ceramic mass makes it possible to improve the technological and physical-mechanical properties of the mass, as well as to increase the strength of finished products. Tab. 4.

An effective method for preparing the surface of steel for single-layer enamelling by boriding in solid solutions has been developed, which makes it possible to shorten and make more economical and clean the process of metal pretreatment without the use of special equipment. Tab. 2, ill. 3, bibliography: 9 titles.

On the basis of crystallizing alkaline borotitanosilicate glasses with additions of oxides of the R ₂ O ₅ type, ground and coating chemically resistant enamels for steel have been developed, characterized by high electrical conductivity. Il. 1, bibliography: 5 titles.

The possibility of obtaining low-melting glasses with the use of phosphate ore processing products as one of the charge components has been investigated. Glasses of different shades of green, yellow and brown with satisfactory properties have been synthesized. The resulting glasses have a unique decorative effect that reproduces the texture of ornamental stones. Tab. 4, ill. 2, bibliography: 3 titles.