Papers by Keyword: Glass-Ceramic Materials

Abstract: Materials with strong susceptibility with respect to the electromagnetic field, namely, ferroelectric (FE) and ferromagnetic (FM) materials are of great interest for modern electronics. On the basis of ferroelectrics, devices such as varicades, delay lines, phase shifters, etc. are being actively developed. Ferromagnets (primarily ferrites) serve as the basis for directional couplers, circulators, valves, filters, phased antenna arrays, etc. Today, the most common method of creating functional composites, combining dielectric and magnetic properties, is the introduction of classical ferroelectrics, such as triglycine sulfate, Siegnette salt (KNaC₄H₄O₆∙4H₂O), sodium nitrite, etc. in iron-containing matrices. The relevance of this approach is due to the fact that when a ferroelectric is introduced into the FM matrix, it becomes possible to create composite multiferroic materials with two types of ordering (electric and magnetic). In this paper, we study the possibilities of creating glass-ceramic multiferroic materials based on Siegnette salt and barium titanate, introduced in the pore space of ferromagnetic glass, formed by ion exchange between alkaline glass cations and salt melt. For obtaining porous glass-ceramic materials by the method of ion exchange, potassium iron-containing silicate glasses are used in the work. 15K₂O·20Fe₂O₃·55SiO₂, mol. % (KFeSi).

Abstract: The possibility of production of white cover glass-enamel coatings for steel products has been considered. A number of compositions of glass-enamel coatings has been worked out. The obtained samples have been subjected to tests for corrosion resistance, temperature resistance and whiteness index. The peculiarities of crystallization in white cover glass-enamel coatings have been revealed. It is shown that the produced cover glass-enamel coatings for steel products conform to all requirements of GOST R 52569-2006. The application of RGB color model has been considered to determine the color hues of the white enamel coatings.

Abstract: Formation processes and morphology of nanostructured glass ceramic materials containing finely dispersed lead sulfide crystalline phase has been studied by X-ray technique. The spatial ordering of PbS nanocrystals has been revealed which manifests itself by interference effects in X-ray scattering. We have ascertained that important morphology feature of the system is nearly monodisperse size distribution of nanocrystals.

Abstract: Bioglasses and bioactive glass-ceramics have found increasingly wide application in medicine and dentistry. Using sol-gel method, is possible to obtain glass and glass-ceramic bioactive materials of new generation, characterized the higher bioactivity than melted bioglasses. These materials can be produced in various final forms, as powders, thin layers on different base and porous sinters. Production of porous bioactive sinters from gel-derived powders is a new problem and the parameters controlling this process are not recognized yet. The aim of the study was to obtain porous bioactive sinters from gel-derived powders of the SiO2-CaO-P2O5 system of four various chemical compositions (S2, II, I, A2) and the characterization of properties of these new materials. The starting powders differ from each other in the content of the basic components, at the molar ratio of CaO to SiO2 equals 0.2-1.35. To obtain the porous sinters a method of burning additions and deposition of the casting slip on the polymeric sponge was used. Sintering was realized in several stages, at the maximal temperature 1200oC. By selecting appropriate conditions of sintering, a durable material of high open porosity up to 77 % was obtained. Its porous structure was characterized by a prevailing number of small micropores of similar dimensions, uniformly distributed in the material. The phase composition of obtained sinters was determined by the X-ray diffraction method. All sinters represented glass-ceramic materials with apatite, cristoballite and calcium silicates as a main crystalline phases. In order to preliminary determination bioactivity of obtained sinters, test in vitro in simulated body fluid SBF was conducted. It was found that hydroxyapatite formation on the sinter surface occurs only in the case of biomaterials of highest calcium concentration.