UHTC-based matrix as protection for Cf/C composites: Original manufacturing, microstructural characterisation and oxidation behaviour at temperature above 2000 °C.

In space propulsion applications, the development of new ceramic matrix composites with improved resistance to oxidation and ablation at high temperature is needed and ultra-high temperature ceramics-based ones appear the most suitable. Combination of both powder impregnation (ZrB 2 , C) and liquid silicon infiltration enabled manufacturing of UHTC based matrices in C f /C preforms with less than 10 vol% open porosity and various proportions and homogeneous distribution of C, ZrB 2 , SiC and Si. Oxidation behaviour was evaluated on composite structures using an oxyacetylene torch at temperatures higher than 2000 °C. Chemical analyses and microstructural observations before and after oxidation testing evidenced the protection ability of ZrB 2 -SiC-Si matrices thanks to the formation of multi-oxide scales which resisted even tested durations of 6 min and pointed the unharmful presence of residual 12 vol% silicon on the composite for use at high temperature under high gas flows. [ABSTRACT FROM AUTHOR]