The results of determining the high-temperature (up to 1500 ° C) strength in compression (by the example of lightweight fibrous blocks) and bending (dense oxide ceramics) are presented. The measurements were carried out on an Instron 5882 universal setup equipped with a high-temperature resistance furnace.
The main technical characteristics of composites based on pyrophyllite and raw materials from the Kul-Yurt-Tau deposit using phosphate binders have been determined. With satisfactory strength, they have low thermal expansion, low thermal conductivity, high frost resistance and heat resistance. Such materials can be recommended as refractory and structural materials for their use in the temperature range up to 1250 - 1350 ° C, depending on the composition of the initial charge. The production technology for obtaining materials is described. Products and refractory masses have found application in specific enterprises.
As a result of calculating the influence of the volumetric effect of a chemical reaction on the porosity of the formation of the final product for the Al-Ni-Co system in vacuum, it is shown that the synthesized material will have a porosity of 7.6% more than the initial porosity P 0 of the initial sample.
To synthesize the SHS material with open porosity, the initial charge powders were mixed in a ball mill with Al 2 O 3 balls for 1 hour. The finished charge was poured into a graphite mold, which was placed in a vacuum furnace, and the temperature of the charge was brought to the autoignition temperature, then spontaneous combustion of the charge took place.
The phase analysis of the samples, carried out on a DRON-Zm diffractometer, showed the presence of the main phase (CoNi) 3 Al and free Ni. The pore size of the obtained samples was 2 - 2.5 ?m. The open porosity of the samples, estimated by the hydrostatic weighing method, was 42%.
Changes in the structure during heating of composites based on pyrophyllite raw materials from the Kul-Yurt-Tau deposit with a phosphate binder have been studied. The processes associated with the interaction of accompanying rocks with a phosphate binder have a great influence on their compaction and strengthening. The deformations of composites were studied in two temperature regimes: heating at a constant rate of temperature change and during isothermal holding. The results of the experiments make it possible to predict the behavior of materials during service in thermal units of various systems, to optimize the technological processes of manufacturing materials when obtaining products with specified characteristics.
Sintering, phase composition, structure and properties of low-temperature fired porcelain from masses where quartz sand is replaced by marshalite or marshalite with diopside have been investigated. The sintering temperature of porcelain from the investigated masses is lower by 100 ° C (1150 ° C compared to 1260 ° C for the original mass).
The process of manufacturing ceramic filters for a gas analyzer for sampling furnace gases with temperatures up to 950 ° C is described. The proposed technology makes it possible to form a through porous structure with a sequentially changing pore size along the thickness of the filter wall and thereby provide an increased resource of its operation.
Fine-dispersed powders of rare-earth elements (REE) aluminates were obtained by the "wet combustion" method. The solid-phase synthesis of lanthanum-gadolinium aluminate has been studied. It has been shown that the target phase can be obtained at temperatures up to 750 ° C. Firing modes have been found that make it possible to obtain ceramics based on rare-earth aluminates with low open porosity and relative density up to 99% of theoretical.
The change in the mass of silicon samples of different initial density, apparent density, ultimate strength, phase composition during nitriding in the nitrogen pressure range of 0.002 - 18 MPa is traced. It is shown that an increase in the reaction rate of nitrogen with silicon occurs up to a nitrogen pressure of 1.5 MPa; at high nitrogen pressures, the growth of the reaction rate slows down. At a firing temperature of 1710 ° C, ceramics with a relative density of 90% and a bending strength of 540 MPa were obtained. Ceramic parts of an internal combustion engine have been manufactured that are operable under the operating conditions of a real engine.
The results of the study of the possibility of synthesizing pigments based on mervenite are presented, methods of directed regulation of the processes of structure and phase formation for the synthesis of pigments with high physicochemical properties have been developed, the relationship between the temperature and time parameters of synthesis, the content of introduced oxides-chromophores and the type and amount of forming color-bearing phases has been established. providing rich color and a wide range of pigments.
Changes in the phase and chemical compositions, as well as the course of hardening during heating of mixtures with a phosphate binder of pyrophyllite raw materials from the Kul-Yurt-Tau deposit and for comparison of raw materials from the Ovruch deposit, have been investigated. It is shown that the behavior of these materials is similar. The optimal amount of binder has been determined to obtain a durable pressed semi-finished product. To achieve water resistance and the required strength of composites, they should be processed at temperatures of 500 - 600 ° C.
