Davydchuk N. Synthesis of nano-composition powders in system Si – C – N - O and creation of ceramic materials on their basis.

Subject of a study - the processes of the synthesis of nano-composition powder (SiC- C) - Si3N4 - Si2N2O, the structurization of ceramics on its basis and its micromechanical properties. Purpose is the development of conditions and technological parameters of the synthesis of nano-composition powder with the optimum content of the phases of carbide, nitride and oxynitride of silicon and obtaining ceramics on its basis with the high characteristics of hardness and resistance to cracks. Novelty - it is for the first time revealed, that the formation of phase composition and structurization of nano-composition powder influences the form of the carbon-containing source material, the composition of gaseous medium in the working space and the temperature- hour parameters of synthesis. It was for the first time established that during packing of the developed material by the methods of hot extrusion and sintering under the high pressure occurs a change in their phase composition, and also in this case it is established the mechanism of dispersed strengthening of material, which is the formation of the starts of the nanos-particle of the solid solution (SiC- C) in the structure of oxynitride and nitride of silicon. It is for the first time optimized the methods of introduction and concentration of the oxides of yttrium and aluminum with the liquid-phase sintering. The for the first time developed material was used as the abrasive with the grinding of heat-treated alloy steels and hard alloys by positive result - was obtained 8 class of the finish of surface (Ra=0,4).