Evaluation of oxidation behaviors of HfC-SiC ultra-high temperature ceramics at above 2500°C via oxyacetylene torch

Development of materials highly resistant to harsh conditions (including ultra-high temperature) has been a crucial issue for the development of next-generation hyper velocity vehicles. HfC-SiC ceramics have been attractive as suitable candidates for these applications owing to their extraordinarily high melting temperatures. Here, HfC-SiC ceramics with ultra-fine grains, prepared via reactive spark plasma sintering, were tested under an oxyacetylene torch flame for relatively long exposure times (5-30 min). The oxidation behaviors of the samples were carefully characterized by microstructural analysis. Although porous structures were formed due to the generation and escape of gas phases, the mixture of oxidized species composed of HfO2 granules and melted SiO2 phase, acted as an excellent barrier under the condition of severe high-temperature oxidation.