Modification of HfB2–30% SiC UHTC with Graphene (1 vol %) and Its Influence on the Behavior in a Supersonic Air Jet
Е. П. Симоненко, Н. П. Симоненко, А. Ф. Колесников, А. В. Чаплыгин, А. С. Лысенков, Ilya A. Nagornov, V. G. Sevastyanov, Н. Т. Кузнецов
Abstract
Oxidation under exposure to a supersonic dissociated air jet (with heat fluxes in the range 363–779 W/cm2, total exposure time: 2000 s) was studied for HfB2–30 vol % SiC ultra-high-temperature ceramics (UHTC) doped with a lowered amount (1 vol %) of reduced graphene oxide (GO). Doping the ceramics with a relatively low amount of reduced GO (1 vol %) did not prevent a dramatic increase in the average surface temperature to 2300–2400°С. However, the existence time of surface temperatures below 1800–1850°С increased considerably, probably due to an increase in the thermal conductivity of the ceramics. The ablation rate of the material was determined as 6.5 × 10–4 g/(cm2 min), which is intermediate between the respective values for HfB2–SiC ceramics and the ceramics doped by 2 vol % graphene. The microstructure features and elemental composition of the oxidized surface and chips of the material were studied. The structure and thickness of the oxidized near-surface region were determined.