Oxidation of Ceramic Materials Based on HfB(2)-SiC under the Influence of Supersonic CO(2) Jets and Additional Laser Heating

The features of oxidation of ultra-high-temperature ceramic material HfB(2)-30 vol.%SiC modified with 1 vol.% graphene as a result of supersonic flow of dissociated CO(2) (generated with the use of high-frequency induction plasmatron), as well as under the influence of combined heating by high-speed CO(2) jets and ytterbium laser radiation, were studied for the first time. It was found that the addition of laser radiation leads to local heating of the central region from ~1750 to ~2000–2200 °C; the observed temperature difference between the central region and the periphery of ~300–550 °C did not lead to cracking and destruction of the sample. Oxidized surfaces and cross sections of HfB(2)-SiC-C(G) ceramics with and without laser heating were investigated using X-ray phase analysis, Raman spectroscopy and scanning electron microscopy with local elemental analysis. During oxidation by supersonic flow of dissociated CO(2), a multilayer near-surface region similar to that formed under the influence of high-speed dissociated air flows was formed. An increase in surface temperature with the addition of laser heating from 1750–1790 to 2000–2200 °C (short term, within 2 min) led to a two to threefold increase in the thickness of the degraded near-surface area of ceramics from 165 to 380 microns. The experimental results indicate promising applications of ceramic materials based on HfB(2)-SiC as part of high-speed flying vehicles in planetary atmospheres predominantly composed of CO(2) (e.g., Venus and Mars).