Thermal transformation of nanohafniumcarbosilanes

The process of thermochemical transformation of nanohafniumcarbosilane (nano-HfCS) at 1500?°C in various media was investigated. The regularities of the formation of SiC ceramic structures modified with hafnium compounds were analyzed by physicochemical methods.The two-stage thermochemical transformation of nano-HfCS first at 1100?°C in argon and then at 1500?°C in various media: argon, nitrogen, vacuum, air results in formation of a nanocrystalline α-SiC ceramics with a hexagonal crystal lattice, modified with HfC, as the main phase. It is demonstrated that the medium in which pyrolysis of nano-HfCS is carried out at 1500?°C affects only the surface layer of the resulting ceramics: at pyrolysis in argon, carbon oxides and hafnium are produced as additional phases on the surface; in nitrogen, silicon nitride and carbon are formed as additional phases on the surface, and in air SiO₂ and carbon are formed on the surface as additional phases.