VOL 84, No. 4 (2011)

The relationship of the aesthetic properties of porcelain (whiteness and color), its structure and technological factors are considered. The research results demonstrate the possibility of regulating the whiteness of porcelain using high-quality raw materials, mineralizing additives, and optimal firing modes. The use of various methods for determining the whiteness and color of porcelain makes it possible to assess the influence of technological factors on the formation of the color characteristics of the material. Possibility of correlation of values ??of porcelain whiteness determined on spectrophotometers "Spekol" and "Pulsar" has been established. Tab. 3, ill. 4, bibliography: 6 titles.

Methods for determining the dependence of the average distance between particles in monodisperse composites are analyzed. A refined method is proposed for determining the average distance between particles in dispersed systems with an indication of the coordination number, taking into account the volumetric density, system connectivity and the degree of its compaction on the basis of corpuscular and percolation models. A comparison of the calculations by the refined technique with the experiments showed their good agreement. The technique is applicable for composite, porous and colloidal systems. Il. 1, bibliography: 11 titles.

The features of the technology of new types of refractory and heat-insulating materials with high porosity, obtained by duplicating the cellular structure of the polymer base (polyurethane foam) and using the technology of chemical pore formation based on the process of "cold" swelling of inorganic compositions, are considered. The use of electrocorundum, periclase, spinel, zirconium dioxide as a base allows the use of such materials within the temperature range from 1750 to 2200 ° C. In some cases, the developed heat-insulating materials can successfully replace corundum fibrous materials. Tab. 1, ill. 7, bibliography: 2 titles.

The influence of the hydrothermal method for the synthesis of initial powders using chemical reagents and illite clay as initial components on both the phase composition and structure and some properties of mullite-zirconium ceramics has been studied. It is shown that mullite, ZrO2 tetragonal modification predominates in the sintered ceramic material, there are also closed pores. With an increase in the firing temperature and especially with the addition of illite clay, the sinterability and, consequently, the compressive strength increase. The modulus of elasticity with an increase in the temperature difference up to 1000/20 ° С, as with the addition of illite clay, during thermal shock increases to 35 and 95 GPa, respectively, while at 500/20 - up to 20 and 22 GPa. Tab. 2., ill. 8, bibliography: 16 titles.

2011, N 4 The presented studies make it possible to judge the deformation-stressed state of ceramic products in different stages of firing and to establish their effect on the thermomechanical properties of the material. Studies have shown that the introduction of pyrite cinders into the compositions of ceramic masses reduces the elastic modulus in the initial period (up to 400 ° C) by 25 - 30%, and in the temperature range 500 - 1000 ° C - by 5 - 10%. These data indicate the possibility of firing intensification using pyrite cinders. Il. 3, bibliography: 8 titles.

The properties of the powder synthesized from calcium acetate and sodium hydrogen phosphate were studied at the ratio [Ca ²⁺] / [PO ₄ ^3-] of the initial reagents equal to 1. Brushite, monetite, octacalcium phosphate were found in the powder after synthesis. A significant weight loss of 26% upon heating is due not only to the decomposition of the detected phases, but also to the removal of the by-product present in the powder of the reactions occurring during the interaction of solutions of the starting materials consisting of sodium acetate and acetic acid. After firing at temperatures above 900 ° C, the phases ?-Ca ₂ P ₂ O ₇, ?-Ca _{were found in the samples 3} (PO ₄) ₂ and Ca ₁₀ Na (PO ₄) ₇. Tab. 1., ill. 6, bibliography: 13 titles.