The fundamental possibility of obtaining corundum ceramics with density close to theoretical, with defect-free polished surface, with low roughness, using as a starting material finely dispersed non-aggregated electrocorundum modified with magnesium oxide with nano addition of aluminum oxide during sintering under SPS conditions
A study of the influence of the addition of aluminosilicate cenospheres (ASC) of 2 fractions on the structure and properties of ceramics with waste from the production of mineral wool (MW) was carried out. The effect of different amounts (from 10 to 30%) and different fractions (0.125 – 0.250 mm) and less than 0.125 mm ASC on the physical and mechanical properties of ceramic specimens after firing at temperatures of 1000 – 1080 °C was determined. It has been established that the combined use of MW as a non-plastic additive and ASC of 2 different fractions makes it possible to obtain durable lightweight ceramics with low shrinkage and high porosity
The necessity of developing a new design of the pendulum clamshell for the formation of mineral wool products is shown. One of the possible variants of the design of mechanical-driven pendulum clamshells has been developed, its structure and operating principle have been described. Analytical dependences for calculating the design parameters of a pendulum clamshell are given, which allow determining their optimal values. As an example, the parameters of the kinematic scheme of a pendulum clamshell for industrial applications are calculated
We compared the granulometric composition of raw and acid-activated rocks containing aluminosilicates. We showed that during the presence of rocks in water, they gradually dissolve with a simultaneous decrease in the particle size, which is associated with the disaggregation of large particles, the diffusion of water into the interparticle space and the hydrolysis of aluminosilicates. We studied the effect of acid treatment on the adsorption-structural characteristics of diatomite. We showed the possibility of using of granulometry for a rapid assessment of the operational properties of acid-activated sedimentary rocks
The study of the ZnO–SnO2 system was carried out, in particular, the possibilities of the synthesis of zinc orthostannate were considered. The temperature of the synthesis of a compound from simple oxides by solid-phase synthesis has been established. Obtained ceramics based on zinc orthostannate with additives 5; 7.5; 10 mol. % NiO and 5; 7.5; 10 mol. % MnO. The properties of the powders were studied using XRD, SEM, and BET. The synthesis temperature of dense ceramics was 1450 °C
The magnetic and some physicochemical properties of glasses based on barium-borosilicate eutectic with additions of iron and lithium oxides have been considered. Increasing in the Fe2O3 content leads to an in-crease in the magnetic permeability. The combined introduction of Fe2O3 and Li2O has no effect on the magnetic permeability. The formation of structural configuration of barium hexaferrite in glass is responsible for the magnetic properties. According to EPR data, a part of iron ions is present in tetrahedral coordination, incorporating into the structural glass network, and the other part is present in the octahedral coordination acting as a modifier
With an increased (in comparison with conventional water treatment) concentration of ozone, pesticides and hydrocarbons are effectively eliminated from water, while elimination without ozonation requires activated carbon.
Currently, the most widespread method of ozone production is its generation in the area of barrier discharge in an ozone generator. However, the performance of this equipment directly depends on the service life of the dielectric barrier, which is primarily determined by the intensity of the impact on the dielectric directly by the electric field and the high-temperature effect of the microdischarge channels, as well as by the dielectric barrier material (insulating enamel). The use of enamels makes it possible to significantly reduce the thickness of the dielectric barrier, increase the power and productivity of the ozone generator, improve the conditions for electrodes cooling, and makes it possible to create high-frequency ozone generators operating at high-frequency currents. Also, important advantages of enameled electrodes are simplicity of design, small dimensions and low specific quantity of metal. The mass of such equipment with the same performance is 10 times less than a low-frequency one. At the same time, thermal coefficient of linear expansion values level must be the same as the metal. The highest values of dielectric properties are characteristic of low-alkali and alkali-free glasses and enamels containing a minimum number of current carriers: they have higher electrical resistance and lower dielectric losses than alkaline compositions. According to literature, SiO2–PbO–B2O3–Sb2O3 chemical system glasses were selected as objects of research to obtain Pb silicate enamels, which are characterized by good flowability and high adhesion to steel, as well as high chemical resistance. When firing Pb enamels, chemical processes take place at the metal-enamel interface, which create a strong adhesion of the enamel to the substrate
The aim of this paper is to find the patterns in forming the microstructure of cermet composites prepared via spark plasma sintering. The composites consist of grained thermoelectric bismuth telluride, Bi2Te3 (a matrix of the composite), and ferromagnetic filler) Ni or Fe). It was found that under spark plasma sintering, the filler inclusions are forming as locally-gradient shell–core inclusions (Ni@NiTe2 and Fe@FeTe2), which are randomly distributed inside the textured Bi2Te3 matrix. Main parameters of composites microstructure (texturing degree and inclusions size) are strongly dependent on filler content
The article considers a possible approach to obtaining a high-temperature composite material with a matrix based on aluminum oxide reinforced with zirconium oxide. The article describes a method for manufacturing samples of ceramic composite material. A comparative study of the compositions and technological methods of manufacturing ceramic composite material is carried out. The prospects of the CСМ composition based on mullite modified with zirconium oxide are substantiated. The advantage of obtaining ССМ by semi-dry pressing is described. The choice of the further direction of development is justified
The features of batch mixing for flint and heat absorbing bronze glass melting containing selenium are considered. Methods to decrease selenium losses during glass mixture transportation and glass melting are presented. The possibility of using diatomite and soluble sodium silicate for these purposes is investigated
