Glass and Ceramics最新文献

This study presents a review of progress in the sol-gel method for the synthesis of powders of ferroelectric ceramics based on the PbTiO₃–PbZrO₃ system, which involves the controlled hydrolysis of the mixtures of salts or organometallic compounds of lead, zirconium, and titanium. To obtain materials based on the PbTiO₃–PbZrO₃ system, attention is paid to the sol-gel conditions, heat treatment conditions, raw materials, conditions to obtain precursors, gels drying, and PbTiO₃–PbZrO₃ powder crystallization.

This work discusses ceramic filter materials used as substrates to study biological objects by electron microscopy. The composition, structure, pore sizes, and morphology of ceramic substrates made of foamed silicate prior to and following the application of inverse silicon oxide opals were evaluated by x-ray diffraction analysis and SEM method. Adescription of the use of the obtained filtering substrates in an experiment with biological objects is given. The substrates seem promising for electron microscopy, since they can be used for sample preparation of biological objects with the use of metal spraying or ionic liquid. This technique, together with the filtering porous material and the technical capabilities of the microscope, preserves the physical characteristics of biological objects.

Using glass as a structural element that could obtain the role of the primary load-bearing elements of iconoclast structures has had a superficial history. Because of its aesthetic and admissible mechanical properties, glass has been considered one of the structural elements in the construction industry. Because of its extrasafety, laminated glass on top of the most widely used elements has been appraised with more depth. The study aimed to evaluate the failure modes in laminated glass and the possibility of detecting the pre-failure status of the surveyed elements, referring to the proffered approaches and image processing (IP) procedures in the literature. The outcomes have compared the peculiarity and strength points of various routes and have reached the inference for proper approaches in every procedure. According to the results, image processing (IP) is the most appropriate method of pre-failure detection in load-bearing laminated glass elements. Among the image processing (IP) techniques, digital image correlation has the widest application. The results of this study, in combination with other pieces of research, may propound a database for evaluating the failure status of glass structures.

The process of obtaining hafnium diboride via the carbothermal reduction of hafnium oxide, which involves heat treatment in a vacuum furnace and a spark plasma sintering unit, was studied. When the charge was heat treated in a vacuum furnace, hafnium diboride powder characterized by the presence of secondary crystalline phases was obtained within a temperature range of 1500 – 1700°C. Monophase hafnium diboride powder having a fine-grained uniform structure was obtained using the spark plasma sintering method at a temperature of 1500°C.

The article investigates the high-temperature interaction and sintering processes of samples of low-temperature firing high-alumina for technical ceramics based on the kaolin – alumina-containing component – dolomite ternary system and establishes the areas of formation of high-alumina body for technical ceramics on the ternary diagram. It is shown that as a result of high-temperature interaction, the formation of new crystalline phases of minerals occurs, including mullite, corundum, β-cristobalite, as well as in a small amount of anorthite and an amorphous glassy phase, which impart the necessary physical and mechanical properties to the fired sample. The area of optimal compositions for obtaining low-temperature sintering high-alumina ceramic bodies based on the kaolin – alumina-containing waste – dolomite ternary system was determined.

In this work, a study was made of the possibility of obtaining ceramics for microwave technology in the system of ZrO₂–SnO₂–TiO₂ oxides by solid-phase synthesis using a sintering additive, lanthanum (III) oxide. Ceramics based on zirconium-tin titanate composition Zr_0.8 Sn_0.2 TiO₄ with additions of 2, 4, and 6 wt.% La₂O₃, its properties were studied using various methods of analysis. The densest ceramic specimens were obtained at a firing temperature of 1400°C and a La₂O₃ content of 4 wt.%.

Refractory and heat-resistant materials with a coarse-grained and large-porous structure were obtained using silica glass suspensions with mullite, spinel, alumina, and quartz fillers. The influence of sintering temperature on the phase composition, structure, porosity, and density of the materials were studied. Although the strength of the ceramics was found to increase in the temperature range 1300 – 1400°C, it decreases at 1500 – 1600°C due to the crystallization of the silica glass. Composites in the silica glass-alumina system were found to have the most stable strength characteristics.

The possibility of using the enrichment tailings of KMA ferruginous quartzites is considered. The chemical composition of waste from Lebedinsky MPP was investigated. It was established that the main components of the waste are quartz, magnetite, as well as dolomite, calcium, and magnesium carbonates. It is shown that the chemical composition and particle size distribution of waste are characterized by stability, which allows it to be used as a corrective additive to ceramic mixtures in the production of wall ceramics.

The chemical composition and technological properties of clay polymineral raw materials from the northwest of the Orenburg region were studied. On the basis of the chemical composition, the raw material can be attributed to semi-acidic sanded clays with a high content of coloring iron oxide Fe₂O₃ (4.83%). The dependences of the viscosity of clay suspensions at sufficiently high concentrations (up to 0.16 vol.%) are defined; the linear character is confirmed by a high correlation coefficient and plasticity of the raw materials, studied in two ways — by pressing the balls and bending the bands. This indicates a high content of sand. Sintering in the temperature range from 600 to 1000°C did not occur, resulting in the sample cracking. Macroparameters of sintering and color parameters of samples under high temperature, as well as the phase composition, suggest unsatisfactory mechanical characteristics of ceramics from the studied raw materials. Low sorption properties of mineral raw materials with respect to copper and lead ions were established. It is shown that the use of this raw material in the ceramic industry is impractical. It is recommended that the materials be used in road construction, landscaping, and as thinning additives to reduce the plasticity and shrinkage of clays during drying and firing.