Preparation of ceramic materials using supercritical fluid chemical deposition

Abstract

This paper relates an unconventional technique based on the supercritical fluid technology for manufacturing dense ceramic matrix composites, which is known as the Supercritical Fluid Chemical Deposition process (SFCD). By using a conventional precursor in a solvent above its critical coordinates, it is possible to faster the deposition rate of a SiC-based matrix on fibrous preforms in comparison to the Chemical Vapor Deposition technique for which a low pressure (1–50kPa) is recommended for a similar range of temperatures 800–1000°C (mixture N2: tetramethylsilane 99.2:0.8vol.%). The microstructure of the coating or matrix is characterized by optical microscopy, Spectroscopy Electron Microscopy and Electron Dispersive X-ray spectroscopy. The influence of the main experimental parameters (temperature, pressure, residence time) is studied on the chemical composition of the ceramic deposits. The opportunity to tune the C:SiC molar ratio opens the door towards multilayered interfaces exhibiting multifunctional properties.