The factors influencing the sintering process of quartz ceramics are considered. The analysis of the dependence of the density of the workpieces after firing on the properties of a slip based on quartz glass has been carried out. An assumption is made about the influence of the content of highly dispersed SiO 2 particles in the slip on the properties of the ceramic material. The concept of a colloidal component is described. Analysis of the particle size distribution in the colloidal component
A study of the stiffness characteristics of fiberglass supports with a taper angle & # 8776; 89 & # 176 ;. A method for determining the modulus of elasticity in tension and compression in the longitudinal and transverse directions of the composite support is proposed. Experimental studies have been carried out to measure the elastic modulus in the longitudinal and transverse directions, formulas and numerical methods have been proposed for calculating the elastic modulus and Poisson's ratio in the transverse direction. It is shown that the modulus of elasticity in tension exceeds the modulus of elasticity in compression
Elemental analyzes of ceramic samples over 1000 years old showed that the main chemical elements are, & # 37 ;: for samples: the outer part of the bricks: 24.45 Si; 14.31 Ca; 12.68 C; 11.55 Al; 5.60 Fe; 4.29K; the inside of the bricks: 32.23 Si; 17.66 Al; 12.66 Fe; 5.52K; 3.07 C; 1.36 Ti; 1.34 Ca; inclusions in bricks: 53.11 C; 13.40 Ca; 5.46 Si; 3.08 Al; 2.63 K; 1.78 Fe. It was determined by X-ray phase and electron microscopic methods of analysis that the strength properties of ceramic samples are given by mullite, anorthite and wollastonite. In addition, the presence of closed porosity in ceramic specimens with isometric and oval pores contributes to increased durability.
The influence of the introduction of the superplasticizer & # 171; Polyplast SP-3 & # 187; into a concrete mixture, which made it possible to regulate the construction and technical properties of concrete. The acceleration of the setting speed of the composition with the additive due to its peptizing effect has been established. At the same time, an increase in the strength indicators and frost resistance of the modified concrete was found.
A study of the properties of lightweight geopolymer materials (GM) based on refractory technogenic waste of aluminosilicates has been carried out. The effect of the ratio of oxides SiO 2 and Al 2 O 3 in the compositions of GM on the physical and mechanical properties of GM has been investigated. It was found that a decrease in the ratio SiO 2 / Al 2 O 3 in the composition of GM leads to an increase in density and strength, and a decrease in water absorption of samples after exposure. After firing at temperatures of 800 and 1000 & # 176; C, the strength of the samples is the higher, the lower the ratio of SiO 2 / Al 2 O 3 in the composition ... The heat resistance of samples with a high ratio SiO 2 / Al 2 O 3 is four thermal cycles, and with a low ratio, more than seven cycles
Within the framework of the quasi-static problem of thermoelasticity, the effect of pulsed laser radiation on a plate is considered. An analytical relationship is obtained, which is the condition for the thermal strength of the plate and allows one to determine the non-destructive modes of laser processing for the case when the diameter of the laser beam is less than the diameter of the processed plate. Experimental verification of the results obtained
Samples of models of power transmission line supports based on basalt and glass roving in the form of pipes with five different winding schemes: longitudinal-transverse, spiral-longitudinal, spiral-longitudinal-transverse and spiral with an angle of 30 and 60 & # 176; to the mandrel axis. Studies of elastic-strength properties during transverse bending tests were carried out and it was shown that the highest values ??of the elastic modulus are provided by the longitudinal-transverse winding scheme, the smallest - by spiral winding at an angle of 60 & # 176; to the axis. The modulus of elasticity of basalt plastic pipes is slightly lower than that of fiberglass pipes, which can be explained by the lower linear density and more uniform laying of the used glass roving.
A method for the synthesis of copper ferrite is proposed, which consists in the anion-exchange precipitation of copper (II) and iron (III) from solutions of their salts in the presence of tartrate ions as a complexing agent, followed by calcining the resulting precipitate. By the methods of chemical, complex thermal and X-ray phase analyzes, IR spectroscopy, scanning electron microscopy and micro X-ray spectral analysis, both precursors and products of their heat treatment have been studied; also studied the magnetic properties of the obtained samples. The presence of a ferrimagnetically ordered phase in the synthesized materials and the proximity of their magnetic properties to bulk CuFe 2 O 4
The results of an experimental study on the generation of X-ray radiation using a ceramic piezoelectric transformer installed in a vacuum are presented. X-rays were emitted by operating a piezoelectric transformer at a resonant frequency of about 20 kHz. In the measured X-ray spectra, a peak of the characteristic radiation of a titanium target with an energy of 4.5 keV is observed against the background of bremsstrahlung. The maximum energy of X-ray bremsstrahlung reaches 12 keV. This means that electrons are accelerated in vacuum in the field of a piezoelectric transformer to an energy of at least 12 keV
The features of the processes of mechanochemical interaction in the Ca (OH) 2 -Al-H 2 O system were investigated using the methods of X-ray phase, X-ray structural and synchronous thermal analysis. It is shown that the joint mechanical activation of the initial components in the ratio of Ca (OH) 2 : Al = 1: 2; 1: 4; 1:12 and further heat treatment at 1000 ° C leads to the formation of aluminates with the same molar ratio. Studies of the specific surface area and mechanical strength of the synthesized samples have established that calcium hexaaluminate has the highest performance.
