© 2020 Elsevier Ltd Effects of the polymer infiltration processing (PIP) temperature between 850 and 1050 °C on the mechanical and thermal properties of Nextel 312 fibre SiCO ceramic matrix composite were studied. The aim was to optimise the material system for its proposed application as a mechanical gas-seal at temperatures up to 900 °C. The microstructure and its failure behaviour at room temperature were characterised using electron microscopy (SEM, TEM), X-ray diffraction and high resolution X-ray Tomography, with mechanical testing by nano-indentation, fibre-push out and flexural bending. Thermo-gravimetric analysis quantified the thermal stability. Processing at 950 °C or above gave a combination of high effective elastic modulus, good resistance to mechanical damage from tensile strain and good thermal stability.
