This paper presents the results of the entropy calculation of the equilibrium constants of chemical reactions at liquid-phase sintering of SiC ceramics with eutectic additives. The composition of the charge for sintering ceramics with nanoadditives forming the liquid phase was determined: MnO nano 1.5 wt. % + Al 2 O 3nano 2 wt.% + SiC µm 94 wt. % + SiO 2µm 2.5 wt. %. Possible chemical reactions of liquid-phase sintering of ceramics at a temperature of 1800 °C in a weakly reducing CO medium were established. The values of the change in the Gibbs energy for all possible chemical reactions at a sintering temperature of 1800 °C were calculated by the method of entropy calculation of the equilibrium constants. The elements of the liquid phase and reinforcing additives were determined.The elements of the liquid phase and reinforcing additives were determined. The structure and properties of finished sintered ceramic samples were studied. Microstructural analysis of ceramics indicated its grain structure with an average grain size of ~10 µm. The main phase components of the ceramics based on silicon oxide were determined. It was found that the sample consists of three main phases: modification of the ring radical of silicate Si 3 O 6 , silicon dioxide SiO 2 and anorthoclase (SiAl)O 4 .
This article describes the results of studying the structural-phase state of composite Co-Cr-Al-Y coatings in the initial state and after thermal treatment, obtained because of using the developed magnetron method for applying multilayer coatings with a controlled concentration of constituent elements. According to the results of SEM measurements, it was revealed that unannealed coatings form dense coatings with a columnar structure. The results of transmission electron microscopy confirm the SEM and EDS measurements, and there are clear layer boundaries in the structure for each type of multilayer coating. A distinctive feature of the synthesized layers is the almost complete absence of a crystalline structure for all types of Co-Cr-Al-Y multilayer coatings, which is apparently due to the amorphous properties of cobalt and its tendency to form metallic glasses. The main process occurring during the heat treatment of the studied multilayer coatings is the formation of a spinel-type phase. The obtained results of experimental studies give new, deeper ideas about the processes of formation of structural-phase states of composite coatings obtained by magnetron sputtering.
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