VOL 81, No. 12 (2008)

The results of studies of the water resistance of float glass from different manufacturers (both original and tempered) are presented. It was revealed that for heat-absorbing and colorless float glass there is an asymmetry in the water resistance of molded surfaces: the water resistance of the lower surface is better than the upper one, by about 2 times. It is shown that in the process of tempering the water resistance of glass decreases, while the asymmetry of the water resistance of the surfaces remains. Based on the results obtained, it was concluded that the water resistance of float glass depends on its chemical composition and technological parameters of production. Tab. 3, ill. 1, bibliography: 3 titles.

The processes of activated sintering of oxide powders with different histories are considered. It is shown that there are two regions of particle sizes, more or less than 1 ?m, in which the mechanisms of compaction and hardening are significantly different. In this case, the general nature of deformation - diffusion-viscous flow - remains unchanged. Bibliography: 15 titles.

Sintering of heat-resistant beryllium oxide ceramics, formed by hot casting with the use of intense ultrasound, has been studied. It was found that changes associated with the homogenization of the material and a denser packing of powders at the stage of molding, as well as with the destruction and growth of defectiveness of particles, contribute to the intensification of sintering and make it possible to reduce the sintering temperature (50 - 150 ° C) and reduce shrinkage (10 - 20% ). Tab. 1, ill. 5, bibliography: 4 titles.

The sol-gel process of forsterite synthesis from magnesium acetate and tetraethoxysilane (TEOS) has been studied. The influence of the conditions of hydrolysis of TEOS on the morphology and phase composition of powders was studied. It was found that a stable sol, which turns into a gel, forms a solution of magnesium acetate and a hydrolyzate of TEOS in an acidic medium. In this case, the forsterite yield after heat treatment at 800 ° C is 97%. Carrying out hydrolysis in an alkaline medium and combining hydrolysis and precipitation of magnesium hydroxide provide a weakly aggregated powder with a composition close to monofractional, but increase the temperature of forsterite synthesis. Tab. 1, ill. 3, bibliography: 5 titles.

The results of the study of the influence of the electric field on the viscosity of thermoplastic ceramic slips VK95-1, VF52.42-1 and on the deformation of castings when the organic binder is removed are presented. It was found that when a constant electric field is applied, the viscosity of the thermoplastic slip decreases, with an increase in the field strength from 10 ³ to 10 ⁶ V / m, the viscosity decreases 3 times. The electric field contributes to the preservation of the shape of the ceramic casting (without deformation) during the removal of the organic binder from it and makes it possible to significantly (6 times) reduce the duration of this technological operation. Tab. 1, bibliography: 6 titles.

Taking into account the experimental determination, the possibility of calculating the LTEC, viscosity and surface tension of the melt of the frit of the ground enamel by various methods is considered with a change in the content of Fe ₂ O ₃. Knowing the percentage of the three original frits in the ground enamel and their experimentally found properties, the properties of the ground enamel were determined by additive methods. Tab. 3, ill. 2, bibliography: 2 titles.

The main difficulty in the manufacture of hydroxyapatite-based ceramic materials is their high sintering temperature. Potassium feldspars, low-melting leucite glass, and synthetic alkali-containing compounds were studied as compounds that increase the amount of melt to improve the sintering process. The influence of alkali-containing additives on the processes of phase formation during sintering of compositions based on hydroxyapatite-fluorite mixtures is considered. Tab. 2, ill. 7, bibliography: 5 titles.

The possibilities of producing ceramics from nanodispersed powders of silicon dioxide and hydroxyapatite have been investigated. The obtained ceramics with a fine-grained (3 - 10 ?m) structure. The properties of the initial nanopowder and ceramics have been studied by transmission and scanning electron microscopy and X-ray phase analysis. The glassy materials obtained from tarkosil (silicon oxide) powder are transparent in the ultraviolet range. Strong ceramic samples of hydroxyapatite with a grain and pore size of 1 ?m or less were obtained with open porosity uniformly distributed over the volume. The results of the study can be useful in the design of medical implants based on hydroxyapatite and ceramic membranes with controlled porosity. Il. 3, bibliography: 8 titles.

The results of obtaining ceramic elastic-rigid and elastic-elastic capillary-porous structures are presented and the possibility of their modification into thin-layer semipermeable membranes with filtration properties is investigated. It has been established that the most effective technological methods for the manufacture of ceramic membranes based on spondyloid clay and calcium-phosphate materials are semi-dry multistage pressing of initial powders and casting from suspensions. A comparative study of elastic-rigid membranes of two main compositions was carried out, the presence of a capillary-porous structure and the proximity of the values ??of their gas permeability and filtration rate were established. The study of elastoelastic resorbable and semi-resorbable membranes based on biogenic hydroxyapatite showed that they are promising for use in medicine. Tab. 2, bibliography: 6 titles.