Abstract: Prior to applying an impregnation composition constituted by a solution of at least one phosphate, a part made of composite material is treated in depth by means of an aqueous solution that penetrates into the open internal pores of the composite material, and is then dried. The aqueous solution contains an additive which, after drying, imparts to the composite material, increased wettability by the impregnation composition. The additive contained in the aqueous solution is preferably constituted by at least one wetting agent that is soluble in water and non-ionic, such as an oxyethylenated fatty acid, an oxyethylenated fatty alcohol, an oxyethylenated alkyl-phenol or an ester of a high polyol.

Abstract: A fiber preform is initially consolidated by being impregnated with a thermosetting impregnation composition that contains a ceramic precursor, and by heat treatment at the end of which the precursor has been transformed into ceramic, without passing through a meltable phase. The consolidated preform is then densified. The impregnation composition is constituted by a mixture of a thermosetting monomer and a ceramic precursor polymer, and the monomer is cross-linked during the heat treatment so as to achieve "in situ" cross-linking of the polymer mixture prior to transforming the precursor into ceramic.