The results of X-ray phase petrographic analysis and scanning electron microscopy of aluminum hydroxide powders obtained by chemical dispersion of aluminum-magnesium alloys (with a mass fraction in Mg alloys of 0.6, 6 and 12%), as well as powders obtained by calcining these hydroxides. A mechanism for the formation of the structure of powders at various stages of the technological process of its manufacture is proposed: the product of chemical dispersion of the alloy is a powder after heat treatment in air (1400 ° C, 1 h).
Compositions of green, blue and turquoise ceramic pigments have been obtained using the principles of heterovalent atomic substitution based on calcium aluminosilicate anorthite, replacing calcium and silicon ions with transition elements and aluminum using quartz sand from the Navoi deposit, Samarkand chalk and alumina-containing waste of the Shurtan gas chemical complex. The physicochemical properties of pigments have been studied. On the basis of the developed compositions of ceramic dyes, an experimental-industrial batch of decorative majolica was produced.
The optimal conditions for the synthesis of nanopowders partially stabilized by yttrium (molar fraction 3% Y 2 O 3 ) of zirconium dioxide by the glycine-nitrate method and the modes of obtaining high-strength ceramics from nanopowders by the method of semi-dry pressing and sintering have been found. ...
The effect of nanosized hydrosols and organoxogel of aluminum oxide on the properties of aqueous suspensions modified with nanosols of bentonite and refractory clays has been investigated. The dependence of the properties of modified bentonite and refractory compositions on the type of nanosol and the effect of an electromagnetic field was analyzed based on the change in the increment, fluidity of the slip, structure of the sol, shrinkage and strength of the fired samples.
The analysis of integral and local compaction during sintering of ceramic materials is carried out. A model is proposed that describes the structure of the material during sintering and takes into account the process of clustering of particles constituting the material. Formulas for micro- and macroporous space (coordination number, specific surface area and average pore size) and an algorithm for their calculation are obtained. The calculation according to the model showed that at the beginning of sintering the size of macropores sharply increases.
The regularities of the process of interaction of amorphous potassium polytitanate with titanium oxide in the process of firing their mixtures taken with different content of components are investigated. The mechanism and sequence of phase transformations in the studied mixture are analyzed. It was found that the introduction of titanium oxide into potassium polytitanate leads to the formation of a denser ceramic structure consisting of compacted potassium hexatitanate nanofibers stabilized by TiO 2 crystals.
The behavior of a mixture of oxide powders was investigated in the process of pressing blanks. The entire pressing process can be conditionally divided into three main stages, differing from each other in the stability of the ensemble of structural elements of the seal, the possibility of their configurational restructuring or destruction when critical values ??of external forces are reached. A method is proposed for determining the value of the optimal pressure, which can be attributed to express methods, since the value of this pressure is determined on raw blanks.
It is shown that melting a mixture of TiO 2 + BaCO 3 and TiO 2 + SrCO 3 on the focal plane of the radiation heating installation with a density of 100 W / cm 2 leads to the synthesis of barium titanates BaTiO 3 and strontium SrTiO 3 . Specimens prepared on the basis of a crushed melt, after sintering at a temperature of 1350 ° C, exhibit higher values ??of mechanical strength and dielectric constant in comparison with specimens of barium titanate obtained by ceramic technology.
The results of studies on the synthesis of ceramic pigments based on titanomagnetite using zinc, magnesium, cobalt and manganese oxides as modifying additives are presented. The phase compositions of the obtained pigments were determined by the method of X-ray phase analysis depending on the composition and synthesis temperature. The optimal compositions of pigments and synthesis conditions have been determined.
The composition of the heat-insulating porous material based on serpentinite has been developed. The natural components used in the charge, including serpentine and lake diatomite, make it possible to obtain a material with a forsterite content of more than 70%, the synthesis of which begins at 600 ° C, and to provide, in comparison with the known composition, high strength. High values ??of mechanical strength and low thermal conductivity allow the use of heat-insulating material for heating units and freezers.
