Abstract: The present invention relates to refractories with a composition gradient for lining the interior surface of combustion chambers. The invention envisages the use of refractories characterized by the presence of a number of layers with a different chemical composition to form a gradient along the cross section of the material. The presence of the composition gradient serves to combine the corrosion resistance of the surface layer, facing towards the inside of the combustion chamber, with the shock resistance of the bulk material.

Abstract: The present invention relates to refractories with a composition gradient for lining the interior surface of combustion chambers. The invention envisages the use of refractories characterized by the presence of a number of layers with a different chemical composition to form a gradient along the cross section of the material. The presence of the composition gradient serves to combine the corrosion resistance of the surface layer, facing towards the inside of the combustion chamber, with the shock resistance of the bulk material.

Abstract: Ceramic matrix composites (CMC) of high density, preferably of the type SiC/SiC, are provided by a production process based on the infiltration of ceramic fiber cloths with a polymeric precursor solution containing, as fillers, inert powders having size much lower than the mean distance among the ceramic fibers which are used as basic material for the manufacturing of CMC, typically a nanometric granulometry. Such step is followed by the steps of hardening the cloths, pyrolysis of the polymer and repeated thickenings until the desired density is reached. A possible alternative process comprises a brief (<24 hours) treatment of infiltration of SiC from the vapor phase (CVI) with precursors and typical operative parameters for the deposition of silicon carbide followed by the repeated thickenings.