Synthesis of a Nitride-Containing Composite by Nitriding a Ferrosilicon–Shungite Mixture in a Combustion Mode

Synthesis of Si₃N₄–SiC–Si₂N₂O–Fe₃C–Fe powder composite has been carried out in a layer-by-layer combustion mode using ferrosilicon and shungite dust waste as raw materials. The influence of the main synthesis parameters (mixture composition, gas pressure) on the phase composition of combustion products was established. The microstructure of combustion products is represented by intergrowths of small faceted crystals and crystals in the form of thin plates of irregular shape. The process of high-temperature interaction of a ferrosilicon–shungite mixture with gaseous nitrogen was studied using differential scanning calorimetry. It has been shown that, at 600–1070°С, the shungite carbon burns out. The process of active nitriding of ferrosilicon is carried out at a temperature of over 1270°С. The mechanism of chemical transformations during the interaction of ferrosilicon with shungite additives in a nitrogen atmosphere was studied.