Astapov A.N. , Zhestkov B.E. , Lifanov I.P. , Terentieva V.S.
DOI Number XXX-YYY-ZZZ
Conference Number HiSST 2018_2990962
The degradation processes of structure of system Si-TiSi2-MoSi2-TiB2 heat resistant coating in hypersonic air plasma flows were studied. It is established that the working capacity of the coating at temperatures on the surface of Tw ≤ 1820÷1830°C is provided by the structural-phase state of its micro composite base layer and by the formation on the surface of a passivating heterogeneous protective film based on borosilicate glass film reinforced with rutile microneedles. The mechanism of degeneration of the coating at Tw ≥ 1850÷1860°C consists of the erosion entrainment of the oxide film combined with generation and growth of gas-filled cavities at the interface «main coating layer – oxide film». When the saturated vapor pressure of the gaseous oxidation products (SiO, CO) exceeds the pressure values of the external environment, the integrity of the oxide film is broken, and the oxidation process goes into the active stage. The coating is designed to protect highly refractory materials against high temperature corrosion and erosion in oxygen containing gas flows.