Glass and Ceramics最新文献

The phase composition of the powder synthesized from aqueous solutions of sodium silicate Na₂SiO₃ and iron sulfate FeSO₄ at the molar ratio Fe/Si = 2, as determined by x-ray diffraction (XRD) data, included hydrated sodium iron sulfate Na₂Fe(SO₄)₂ · 4H₂O and an x-ray amorphous product based on hydrated iron and silicon oxides. The phase composition of the powder obtained by fourfold washing of the synthesized powder in distilled water was represented by an x-ray amorphous product.

Following firing in the air at temperatures ranging from 400 to 1200°C, hematite (Fe₂O₃) and cristobalite (SiO₂) were identified in powder samples and the corresponding ceramics. Following firing at 900°C in graphite powder bedding, the phase composition of ceramic samples included magnetite (Fe₃O₄), laihunite (Fe_4.74(SiO₄)₃), and fayalite (Fe₂SiO₄). The powder prepared from the product isolated from the mother liquor included hydrated sodium iron sulfate, Na₂Fe(SO₄)₂ · 4H₂O, and sodium iron sulfate hydroxide hydrate (metasideronatrite), Na₄Fe₂(SO₄)₄(OH)₂ · 3H₂O. Following heat treatment at 400°C, sodium iron sulfate (Na₃Fe(SO₄)₃) was identified as the predominant phase in the powder. Powders resulting from the interaction of aqueous solutions of sodium silicate and iron sulfate can be used in the manufacture of high-temperature dyes and materials with magnetic properties, the creation of analogs of lunar or Martian regolith, as well as the development of functional (cathode) materials for Na-ion batteries.

The study reviews the current progress in the sol-gel method for the synthesis of ferroelectric powders, thin films, and rods in the lead zirconate-titanate system. In addition, it examines methods for obtaining controlled particle morphology, primarily rod-like. The synthetic approaches in the sol-gel process and heat treatment conditions for obtaining lead zirconate-titanate ceramics of pre-defined morphology are the primary focus of the present review.

Glass and glass ceramics containing 40 wt.% of heavy metal oxides (Bi, Ta, and W) were obtained for use in medicine as radiosensitizers. The properties of the composites were studied in vitro, including the generation of secondary radiation, chemical solubility, and the variations in the pH of the medium during resorption. The results demonstrated that the secondary radiation indicators and pH value of the medium decreased in the order: W > Ta > Bi. Solubility indices decreased in the order: W > Bi > Ta. Despite the highest generation of secondary ionizing radiation, W-containing ceramics based on Bioglass 45S5 are unsuitable for in vivo use due to their rapid dissolution and high alkalization of the environment.

The optical properties and microstructure of composites based on yttrium aluminum garnet were studied. The composites were produced by vacuum sintering of pre-formed compacts of nanocrystalline powder (Y₃Al_4.995Cr_0.005O₁₂) with a YAG single crystal. The transmittance spectra of the composite samples exhibited the presence of Cr³⁺ absorption bands following vacuum sintering, as well as Cr⁴⁺ bands following annealing in air. The impact of varying heating rates during vacuum sintering on the transmittance of composite samples was examined. It was determined that the optimal heating rate during the vacuum sintering of composites should be less or equal to 120 K/h. In addition, the impact of the vacuum sintering temperature on the optical properties and microstructure of YAG:Cr (ceramics)/YAG:Nd (single crystal) composite samples was investigated. The samples exhibiting the highest transparency were obtained at a temperature of 1850°C. Microstructure studies of the composites revealed the presence of regular residual porosity in the vicinity of the interface, predominantly located in the YAG single crystal. It is postulated that the formation of these pores occurs during the fusion of ceramic grains with a single crystal during sintering.

This paper presents a process for obtaining glass ceramics based on corundum modified by borosilicate glass with various additives. The described Al₂O₃ /SiO₂–B₂O₃–CaO–MgO–Na₂O–K₂O system has been developed for use in LTCC technology and exhibits a sintering temperature of less than 950°C. The impact of varying the sintering additive content on the firing temperature, microstructure, ceramic, and electrophysical properties of the resulting ceramics was investigated. The developed material exhibited a dielectric constant of ε_r= 6.73 – 6.82 and tangent of the dielectric loss angle of tan δ = 8.0 – 8.6 × 10 ^–3 at a frequency of f = 1 MHz.

The present article describes a method for determining the physico-mechanical properties of a synthesized batch of proppants. Industrial waste is one of the sources of anthropogenic impact on the environment on a global scale, being formed in the process of coal and oil extraction as a by-product.With the decrease in stocks of high-quality natural raw materials and the accumulation of man-made products, the problem of waste utilization becomes urgent.

The possibility of isovalent substitution of zinc and cobalt atoms in the structure of willemite Zn₂SiO₄ was studied. Ceramic pigments with a willemite structure of blue, violet, and light blue colors were synthesized. Samples of blue color were used in the manufacture of glazes. During the synthesis of the pigments, synthetic silicon oxide was replaced by natural quartz sand. The pigments were synthesized by solid-state method at a temperature of 1270°C. The physical and chemical properties of the synthesized blue pigment were determined. In addition, the pigment was tested for use in traditional glazes for the coloring of ceramic products. It was established that the obtained blue pigment provides high aesthetic and decorative characteristics at a relatively low price.

High-temperature insulation materials are used extensively in civil engineering as flame retardant materials, as well as in numerous industrial sectors. The raw materials used in the production of these materials include rocks and industrial waste. The article substantiates the feasibility of using ceramovermiculite and ceramoperlite materials containing a wollastonite binder as high-temperature insulation. The materials were obtained through the firing of a charge containing chalk, diatomite, and a heat-resistant filler (expanded perlite or expanded vermiculite). The material of the fired samples with expanded vermiculite is primarily composed of the crystalline phase of wollastonite and biotite, with a minor amount of quartz and akermanite-gehlenite. The use of expanded perlite as a heat-resistant filler results in the presence of a low amount of plagioclases in addition to the crystalline phase of wollastonite in fired samples, along with an amorphous phase. The physicomechanical properties of the charge and the fired samples were determined, and the effect of the apparent density and phase composition of the developed materials on the variation in their thermal insulation properties at high temperatures was studied. The thermal insulation properties of the materials were determined by supplying heat flow from the heating chamber of the muffle furnace to one side of the sample. The samples from the developed materials exhibited apparent densities ranging from 375 to 630 kg/m³ and compressive strengths between 0.95 and 3.25 MPa. The developed ceramoperlite materials containing wollastonite binder can be used as high-temperature thermal insulation up to +900°C, while ceramovermiculite can be used up to +1050°C. According to a range of physicomechanical and thermophysical properties, the materials obtained are comparable to or exceed the performance of known analogs.

This review presents various interpenetrating phase composite (IPC) materials currently used in computer-aided design/computer-aided manufacturing (CAD/CAM) systems and to evaluates how the optical properties of those materials are affected by various factors. In the field of dentistry, selecting materials compatible with dental tissues is key to clinical success of restorative materials. Understanding the optical properties of a restorative material aids in material selection and provides insights into the material’s clinical performance and esthetic longevity. Such knowledge can in turn help clinicians select the best treatment option for their patients. Interpenetrating phase composite materials combine the optical and mechanical properties of ceramics and composite resins; they are often used in direct/indirect restorative options such as inlays, onlays, veneers, single crowns, implant-supported crowns, and short-span fixed partial dentures with esthetically favorable outcomes. The color of a material, which plays an essential role in the esthetic outcome, can change over time depending on different intrinsic and extrinsic factors. Those intrinsic factors include chemical composition, resin-matrix structure, and filler particle sizes; extrinsic factors include surface treatment protocols, the patient’s smoking status, and the consumption of beverages such as coffee, tea, red wine, fruit juice, cola, etc. To fabricate restorations that complement a person’s natural teeth, it is essential to determine the color properties of these materials (e.g., translucence, hue, chroma, and opalescence).

A mathematical model was developed for the calculation of thermal processes occurring in hexagonally located cells in the form of connected channels with a filler. The proposed model was used to calculate the temperature fields and power of heat flows along a single homogeneous long thin rod of calcium carbonate perovskite embedded in the hexagonally arranged channels of anodic aluminum oxide. In addition, the equations for calculating the distribution of temperature and power of heat flows in the wall of the aluminum oxide channel in the perpendicular direction were derived. The resulting calculations can be used to develop advanced highly efficient solar power electronic devices.