Self-generating oxidation protective high-temperature glass-ceramic coatings for C-f/C-SiC-TiC-TaC UHTC matrix composites

The ablation/oxidation resistance of a carbon fibre (C-f)/carbon matrix (C)-SiC-TiC-TaC ceramic matrix composite (CMC) produced by melt infiltration of alloy into a C-f/C preform and tested in severely oxidising conditions was quantitatively determined and discussed. An oxyacetylene flame shot of 7.5 s (4 MW/m(2) nominal heat flux), as well as oxidising conditions imposed by a radiant furnace in air at 1873 K up to 480 s were the selected testing conditions. Detailed post-test microstructure investigations of the oxidised/ablated infiltrated CMC samples, compared to unprotected CMCs tested in nominally identical conditions, enabled to establish an increase in ablation/oxidation resistance of one order of magnitude. The occurrence of a self-generating protective high-temperature glass-ceramic, disclosed by microstructure analyses, played a substantial role for that performance jump during oxidation/ablation. The C-f/C-SiC-TiC-TaC composite herein tested can be a valuable candidate for uses in severe aerospace applications (propulsion and hypersonic flight). (C) 2017 Elsevier Ltd. All rights reserved.