VOL 84, No. 11 (2011)

The results of studying the properties of low-melting lead-free glasses obtained on the basis of the system ZnO - Bi ₂ O ₃ - B ₂ O _{3 with additional introduction K 2 O, Al 2 O 3 and SiO 2. The limits of change of temperatures of full spreading and temperatures of the beginning of softening are established. The calculated data on the TCLE and the refractive index of glasses are presented. Conclusions are drawn about the probable structural state of bismuth ions. Tab. 1, ill. 5, bibliography: 12 titles.}

New information has been obtained on the structural changes occurring during the fluorination of natural crystalline quartz with ammonium hydrodifluoride. The morphological, structural and phase features of the samples of each stage of the process of fluoride processing of natural crystalline quartz have been studied. Studies of morphology, microstructure and dispersion were carried out by scanning electron microscopy. The phase composition of the samples was determined using X-ray phase analysis and IR spectroscopy. Il. 5, bibliography: 10 titles.

In the temperature range 1400 - 1600 ° C, the deformation of polycrystalline oxide ceramics occurs due to the action of diffusion mechanisms. The course of the deformation curves is very sensitive to the presence of nonequilibrium defects and stress concentrators, which were "hardened" during the cooling process after high-temperature firing during the preparation of materials. Destruction occurs, apparently, as a result of the formation of vacancies in areas of the stretched zone, confined to the boundaries of the crystals, and then their coagulation at the boundaries. The course of the processes of formation and development of cracks is not the same for different materials and depends on their crystal chemical characteristics.

The possibility of obtaining expanded clay of low density and high strength from weakly expanding clay raw materials using a carbon-alkali reagent (UCHR) has been investigated. The features of the formation of the porous structure of expanded clay granules under various temperature and time conditions and its effect on the physical and mechanical properties of the material have been studied. Tab. 1, ill. 3.

A new method has been developed for the synthesis of ceramic composites based on Ti ₃ SiC ₂ using non-powder reaction compositions of titanium and silicon carbide. A ceramic composite with a matrix Ti ₃ SiC ₂ - TiSi ₂ reinforced with SiC particles. The features of the phase composition and microstructure of the obtained material are investigated. Il. 4, bibliography: 13 titles.

In the investigated rocks of talc stone (carbonate-chlorite-talc composition) and accompanying tremolite-chlorite rocks in the temperature range of 950-1100 ° C, the following processes occur: dehydration (talc, tremolite, chlorite), decarbonatization (dolomite, calcite, breinerite) and the formation of new crystalline phases (forsterite, enstatite, clinoenstatite, subcalcium augite) due to the decomposition of talc and tremolite. These processes, as well as the presence of an amorphous phase enriched in magnesium cations, increase the strength of the ceramic. An additional factor for increasing the strength is the larger, slightly changed grains of tremolite due to the tabular and acicular shape, which have a reinforcing effect on the structure of the ceramics. Tab. 3, ill. 2, bibliography: 10 titles.

The technology of high-temperature synthesis of NZP-structures on solar ovens has been implemented. Phase formation in the obtained systems has been studied by X-ray phase analysis. It has been established that Ca, Sr, and Ba phosphates obtained by melting are of the NZP structural type. The possibility of obtaining strong porous monophase NZP ceramic samples by traditional sintering methods has been shown experimentally. Tab. 3, ill. 1, bibliography: 6 titles.

The problems of enamel frits are considered. The compositions of enamels with the use of various mufflers have been worked out. The effect of the muffler on the properties and opacity of the enamel is shown. The reasons for killing the material have been identified. Bibliography: 6 titles.

The issues of the possibility of using composite ceramics based on biogenic hydroxyapatite (BHA) as carriers of cultured stem cells are considered. The results of studies of the microstructure and biochemical activity of glass-ceramic samples based on BHA with a maximum fraction of open porosity, prepared for use as substrates for cloning fibroblast cells in vitro, are presented. The results of a visual assessment using fluorescence microscopy of cell adhesion and their proliferative activity on bioresorbable membrane-type substrates made of a composite material based on biogenic hydroxyapatite are also presented. Tab. 2, ill. 4, bibliography: 8 titles.