The properties of the earthenware surface are determined & # 8211; acidity and aluminosilicate modulus and explained their change depending on the chemical composition with a change in the content of mullite Al 2 Si 2 O 5 , quartz and cristobalite (crystalline modification of quartz SiO 2 ). In accordance with the structure of the surface, the presence of a negative surface charge was determined. It was found that silanol groups on the surface of Si & # 8211; OH earthenware, which have weakly acidic properties, provide physicochemical interaction with polymer film-forming materials with basic properties. The sorption of urea-formaldehyde oligomers of various compositions on faience and subsequent film formation in the presence of polyvinyl alcohol is considered.
Within the framework of the theory of developed evaporation of matter under the action of laser radiation, the problem of assessing the strength of ceramic parts of a cylindrical shape during laser punching of holes in them is considered. Analytical relations are obtained for calculating the power density of laser radiation, which leads to the destruction of the lateral surface of parts by the pressure of gaseous products as a function of the ratio of the hole radius to the radius of the part, the ratio of the radius of the part to the radius of the hole in it, and the thickness of the lateral surface of the part as a function of the power density of the acting laser radiation. Using the example of technical ceramics based on magnesium oxide P-25, the applicability of the results obtained for assessing the strength of cylindrical parts is shown. When the ratio of the hole radius to the part radius is less than 0.3, the part can be considered as an infinite body. In this case, the error in the calculations will not exceed 10 & # 37;
The results of studies of the chemical and mineralogical characteristics of alumina-containing wastes of the gas processing industry and the possibilities of their use for the synthesis of aluminum-magnesium spinel are presented. It was found that the optimal condition for the synthesis of spinel MgAl 2 O 4 by the sol-gel method using alumina-containing waste is a temperature of 1000 ° C and a holding time of 120 min.
Studies of the adhesion strength of an enamel reaction-hardening coating on a heat-resistant nickel alloy VZH171 by the sclerometry method have been carried out. The threshold value of the loads required for the occurrence of cracks in the pavement has been determined. The values ??obtained are high for this type of material and correspond to the level typical for chrome and nickel coatings. The results of microstructural analysis of the tested samples are also shown. Defects occurring in each zone of increasing load are described in detail.
The effect of the thickness and chemical composition of the nickel surface on the vacuum density of VK 94 ceramics after soldering with PSr72 solder has been investigated. It has been established that at a nickel layer thickness of less than 3 ?m, oxides of elements (aluminum, silicon, manganese, molybdenum) are present in its surface, which are part of the metallization. The existing methods for controlling the nickel layer using accompanying samples do not ensure its quality in large batches of parts. A non-destructive method for controlling the thickness of nickel directly on the parts is proposed. The efficiency of the method allows you to control 100 & # 37; parts directly in production conditions. The method is based on measuring the thermoEMF, which is provided for by GOST 9.302 & # 8211; 88 to control the thickness of electroplated coatings. The method has been introduced at a number of enterprises producing metallized ceramics
The research of corrosion processes of glass coating of pipes of pipelines in the conditions of acidic, alkaline and marine environments has been carried out. In an acidic environment, corrosion of the pipe coating is insignificant and the corrosion rate is practically absent. In an alkaline environment, the leaching rate is initially insignificant, then sharply increases. In the range of pH = 6 & # 8211; 12 pipe coatings do not have high durability, and there is an active leaching of the pipe coatings. Experimental studies have shown that during long-term operation, insignificant scale deposits are observed on the surface of glass coatings of pipes, while a significant layer of scale forms in non-glass-lined pipes.
The results of the initial stages of work on assessing the possibility of obtaining whiskers of titanium nitride from the gas phase are presented. A theoretical assessment was made of the possibility of homogeneous formation of micro-substrates of various types and compositions in the gas phase, the conditions for condensation of the titanium nitride phase and the growth of whiskers. Based on the results of the thermodynamic analysis of the system under study, the current critical supersaturations were calculated and the rates of homogeneous condensation in the gas phase of titanium and titanium nitride were estimated.
A clinker brick was obtained on the basis of polymineral raw materials, including low-melting and high-melting clays, loams and granitoid screenings with the plastic method of manufacturing. The relationship between the physical and chemical properties of products on the mass content of components and the oxide composition of the charge is established, the optimal temperature and time modes of firing are determined, which are 1150 & # 177; 5 & ??# 176; C with exposure at an optimal temperature for 4 hours. The obtained data on the oxide and mineral composition allow us to predict the composition of the charge for producing clinker bricks, the modes of heat treatment and properties of products
The influence of a burnable additive in the form of petroleum coke and brown coal on the properties of lightweight heat-insulating materials is considered. It is shown that the high ash content of coal and the increased content of low-melting oxides in the ash activates the sintering process. By the selection of fillers and clay binder, as well as the firing temperature, it is possible to obtain aluminosilicate light weights with an optimal combination of physical and technical properties, such as density, strength and thermal conductivity.
The interaction of lead silicate glasses С87 & # 8211; 2 and С78 & # 8211; 4 with dilute solutions of hydrofluoric acid has been investigated. It is shown that an increase in the temperature and concentration of the HF solution does not lead to an increase in the reaction rate. The results obtained are explained by the fact that, along with the formation of soluble salts, complex compounds with limited solubility appear, which, precipitating on the surface, restrain the release of glass components into solution.
