Steklo i Keramika (Glass and Ceramics). Monthly scientific, technical and industrial journal


ISSN 0131-9582 (Online)

The technology of glass concrete based on dispersed container and sheet glass has been developed. It is shown that when Portland cement and cullet are ground together, when a specific surface area of 5890 – 6450 cm2/g and a particle size of 3.4 – 3.6 microns with a dispersed glass content in the composite of 20 – 50 wt. % with hyperplasticizer glass concrete corresponds to class B30 – B40, which meets the requirements of regulatory documents. The microstructure of glass concrete and the features of its dehydration when heated to 1000 °C investigated. Using X-ray phase analysis, it was found that sodium-calcium hydroaluminosilicates such as gmelenite and thomsonite are formed in glass concrete.
Powders of hydroxyapatite (HA) Ca10(PO4)6(OH)2 treated in 0.25M aqueous solutions of ammonium NH4H2PO4, sodium NaH2PO4 and potassium KH2PO4 dihydrophosphates for 1 hour under stirring were used for ceramics production.
According to the XRD data, there was no changes in the phase composition of the powders after such treatment. After
firing in the range of 900 – 1100 ?С, the phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with an aqueous solution of NH4H2PO4 included ?-tricalcium phosphate ?-Ca3(PO4)2 and HA Ca10(PO4)6(OH)2; The phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with NaH2PO4 aqueous solution included sodium-substituted tricalcium phosphate Ca10Na(PO4)7 and HA Ca10(PO4)6(OH)2; the phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with an aqueous solution of KH2PO4 included potassium-substituted tricalcium phosphate Ca10K(PO4)7 and HA Ca10(PO4)6(OH)2. The formation of biphasic ceramics occurred due to a decrease in the molar ratio Ca/P of HA powder after treatment in aqueous solutions of ammonium NH4H2PO4, sodium NaH2PO4 and potassium KH2PO4 dihydrophosphates. HA-particle surface adsorption of cations and anions from the solution, slight dissolution of HA in solutions of dihydrophosphates with acidic pH, as well as ion exchange of cations and anions of HA for cations and anions from solutions, were possible processes providing change in the ratio of cations and anions in the HA powder. The resulting ceramic composites contain biocompatible phases, and can be recommended for the creation of bone implants.
Samples of Zr0.9Y0.1O2–?–BiScO3 and Сe0.9Y0.1O2–?–BiScO3 solid solutions were obtained by solid-phase synthesis. X-ray diffraction revealed that the Zr0.9Y0.1O2–?–BiScO3 system corresponds to a tetragonal structure with space symmetry group P42/nmc. The Сe0.9Y0.1O2–?–BiScO3 ceramics is two-phase and is characterized by a cubic structure with space symmetry groups and Ia–3. Using the impedance spectroscopy method, it was found that the Сe0.9Y0.1O2–?–BiScO3 system has the highest electrical conductivity, however, the activation energy is lower in the Zr0.9Y0.1O2–?–BiScO3 ceramics, amounting to 0.3 eV in the temperature range of 300–420 ?С and 0.7 eV in the temperature range 420–680 ?С.
The activation energy of the Сe0.9Y0.1O2–?–BiScO3 solid solution is 1.0 eV.
The results of diamond-abrasive treatment of the reverse side of silicon carbide semiconductor plates of polytypes 4H and 6H are presented. Dimensions of surface microcracks of ceramic plates after abrasive treatment with pastes with diamond powder of different grain size are investigated, and also relationship between length of surface microcrack and rate of material removal depending on technological modes of diamond-abrasive treatment is established. As a result, a new method of single-sided abrasion treatment of thin ceramic plates is proposed, which ensures reduction of crack formation.
The results of studying the behavior of analcime-bearing rocks of the Timan region (Komi Republic) under high-temperature firing (1200 – 1280 ?С) were presented. The mineral composition and physical characteristics (apparent density, water absorption, open porosity, thermal conductivity) of the resulting ceramics were determined. The influence of the mineral composition of the initial analcime-containing rocks on the bloating and physical characteristics of fired ceramics was shown. Porous materials with low apparent density (0.37 – 0.39 kg/m3), water absorption (up to 4.3 %), and thermal conductivity (0.09 – 0.10 W/m??С) were obtained. The obtained results show the prospects of using analcime-bearing rocks with a certain mineral composition for producing heat-insulating materials.
The activity of the remarkable scientist V.F. Solinov is considered.
The results of an investigations into the effect of filamentous striae with birefringence from 3 to 15 nm/cm in SO-115M glass-ceramic on the manufacturing quality of optical parts for ring lasers and the exact characteristics of laser gyroscopes based on them are presented. It is shown that the presence of striaes with stresses of no more than 15 nm/cm in SO-115M glass-ceramic does not depend on the speed of manufacturing the resonator optical circuit and the quality of its assembly. The presence of striaes in the output mirror additional backscattered of a ring laser may have the destination of lock-in zone. Correct adjustment of the output mirror allows to reduce scattering and reveal the growth of the lock-in zone in laser gyroscope. It is shown that the accuracy of the laser gyroscope improves by the quality mirror substrates, the geometry of the resonator body, and increases the accuracy of scattering inside the resonator.
The transformation of substances under extremely high pressures and temperatures is an actual direction both in the field
of solid state physics and materials science, and for natural objects. Among the latter, the most interesting are ultrahigh-pressure high-temperature glasses recently found at the Kara giant meteorite crater (Pai-Khoi, Russia), formed from impact melts at pressure about 60 – 80 GPa and the temperature range of 2300 – 2500 °C. These glasses are characterized
by unusual structural and phase state features that require deeper study to clarify their physical properties and the possibility
of using them as prototypes of innovative materials. Experimental modeling of the impact process in laboratory conditions allows to identify the nature of phase transformations during impactogenesis. Here the modeling of the impact process
has been carried out by short-pulse laser radiation (0.5 ms) on the example of clay-containing siltstones and limestones with and carbonaceous components. The impact glasses have been produced from aluminosilicate and quartz components of the host target rocks of the Kara target under pressure conditions ?90 GPa and temperatures ?7000 °C. To study
the synthesized products of the impact glasses, high resolution methods have been used – Raman spectroscopy and scanning electron microscopy with microprobe analysis. The provided studies have shown that under the extreme conditions
the impact glasses of a specific composition containing a high concentration of Ca and carbon are formed. Thus, the experiments conducted have shown the possibility of obtaining glasses of a wide composition, including carbon-containing glass, which can be used for further studies aiming to develop new materials and technologies of their producing.
The article is devoted to the development of an original production method for estimating the specific energy of destruction of ceramic compositions of the “abrasive grain–ceramic binder–pores” system. The results of experimental studies
and theoretical calculations that form the basis of the proposed method. Recommendations for its use are given.
The article presents a study of the properties and structure of underglaze paints with different cobalt pigments and the development on their basis of the composition of the paint for porcelain Gzhel, resistant to changes in temperature and gas environment during firing, as well as less labor-intensive in manufacturing. Underglaze paints based on cobalt oxide and pigments synthesized in the chemical systems Cо–Al–Si and Co–Si have been studied. Their behavior during painting, color characteristics after firing in the range of 1200 – 1320 °C, resistance to the formation of defects with changes in temperature and gaseous medium during firing were analyzed. The relationship between the structure of paints on porcelain and its decorative properties has been established. A paint with an optimal combination of pigments of the Cо–Al–Si and Co–Si systems has been introduced into production, corresponding in terms of decorative effect to paint with Co3O4, but resistant to “metallization” during firing and less expensive.