Sol-Gel Synthesis and Characterization of Novel Y3−xMxAl5−yVyO12 (M—Na, K) Garnet-Type Compounds

In this study, for the first time to the best of our knowledge, the new garnets Y3−xNaxAl5O12, Y3−xKxAl5O12, Y3Al5−yVyO12, and Y3−xNaxAl5−yVyO12 with various stoichiometric compositions were successfully synthesized by the aqueous sol-gel method. All obtained samples were characterized by X-ray diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). It was determined from the XRD results that the formation of monophasic Y3−xNaxAl5O12, Y3−xKxAl5O12, Y3Al5−yVyO12, and Y3−xNaxAl5−yVyO12 garnets is possible only at limited doping levels. The highest substitutional level of doped metal was observed for the YAG doped with sodium (x = 1), and the lowest substitutional level was observed for the YAG doped with vanadium (y = 0.05). Furthermore, the obtained FTIR spectroscopy results were in good agreement with the XRD analysis data, i.e., they confirmed that the YAG is the main crystalline phase in the end products. The SEM was used to study the morphology of the garnets, and the results obtained showed that all synthesized samples were composed of nano-sized agglomerated crystallites

Comparative Study of Structures and Properties of Detonation Coatings with α-Al2O3 and γ-Al2O3 Main Phases

This study is aimed at obtaining a coating of aluminum oxide containing α-Al2O3 as the main phase by detonation spraying, as well as a comparative study of the structural, tribological and mechanical properties of coatings with the main phases of α-Al2O3 and γ-Al2O3. It was experimentally revealed for the first time that the use of propane as a combustible gas and the optimization of the technological regime of detonation spraying leads to the formation of an aluminum oxide coating containing α-Al2O3 as the main phase. Tribological tests have shown that the coating with the main phase of α-Al2O3 has a low value of wear volume and coefficient of friction in comparison with the coating with the main phase of γ-Al2O3. It was also determined that the microhardness of the coating with the main phase of α-Al2O3 is 25% higher than that of the coatings with the main phase of γ-Al2O3. Erosion resistance tests have shown (evaluated by weight loss) that the coating with α-Al2O3 phase is erosion-resistant compared to the coating with γ-Al2O3 (seen by erosion craters). However, the coating with the main phase of γ-Al2O3 has a high value of adhesion strength, which is 2 times higher than that of the coating with the main phase of α-Al2O3. As the destruction of coatings by the primary phase, α-Al2O3 began at low loads than the coating with the main phase γ-Al2O3. The results obtained provide the prerequisites for the creation of wear-resistant, hard and durable layered coatings, in which the lower layer has the main phase of γ-Al2O3, and the upper layer has the main phase of α-Al2O3

Informatization of teaching based on interdisciplinary connections of robotics with other subjects

In this work, the results of a study regarding the methodological aspects of organizing training courses in robotics in a school educational process are presented. In the course of the study, an analysis of the problem was carried out and the conditions for the effective implementation of teaching robotics to students of a comprehensive school based on developing educational technologies, integration processes and interdisciplinary communications were identified. The process of development of the cognitive interests of students in robotics was investigated in one of the specialized lyceum of the Capital city of Kazakhstan. Based on the results of the study, the theoretical foundations of the process under study are summarized, the prerequisites for updating the problem are established, and the scientific and methodological aspects of teaching robotics in the conditions of the school educational process are considered. The results obtained are of theoretical and practical importance for modern education, the implementation of the leading ideas of educational informatization

Effect of Pulsed-Plasma Treatment on the Structural-Phase Composition and Tribological Properties of Detonation Coatings Based on Ti–Si–C

The structural-phase state and tribological characteristics of detonation coatings based on Ti–Si–C before and after pulsed-plasma exposure have been experimentally investigated. The authors of the research used a detonation set-up of CCDS2000 to obtain coatings. The modification of coating surfaces was carried out by a pulsed-plasma flow using the “Impulse-6” installation. The results of the research have shown that the modification of coatings surface by a pulsed-plasma effect causes an increase in the microhardness of the surface layer and in its wear resistance. It was determined that after such type of treatment, there is an increase in the content of the Ti3SiC2 phase. According to the results of XRD analysis, the improvement in the mechano-tribological properties of detonation spraying coatings of the Ti–Si–C system as a result of pulsed-plasma treatment is associated with an increase in the content of Ti3SiC2 phases in the coatings, as well as the formation of carbide and oxide phases on the surface layer

Sol-Gel Synthesis and Characterization of Novel Y_3−xM_xAl_5−yV_yO₁₂ (M—Na, K) Garnet-Type Compounds

In this study, for the first time to the best of our knowledge, the new garnets Y3−xNaxAl5O12, Y3−xKxAl5O12, Y3Al5−yVyO12, and Y3−xNaxAl5−yVyO12 with various stoichiometric compositions were successfully synthesized by the aqueous sol-gel method. All obtained samples were characterized by X-ray diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). It was determined from the XRD results that the formation of monophasic Y3−xNaxAl5O12, Y3−xKxAl5O12, Y3Al5−yVyO12, and Y3−xNaxAl5−yVyO12 garnets is possible only at limited doping levels. The highest substitutional level of doped metal was observed for the YAG doped with sodium (x = 1), and the lowest substitutional level was observed for the YAG doped with vanadium (y = 0.05). Furthermore, the obtained FTIR spectroscopy results were in good agreement with the XRD analysis data, i.e., they confirmed that the YAG is the main crystalline phase in the end products. The SEM was used to study the morphology of the garnets, and the results obtained showed that all synthesized samples were composed of nano-sized agglomerated crystallites