Abstract: The invention concerns a method for making boron nitride fibers by drawing a polymer precursor and treating with ceramics the polymer fibers obtained by drawing. The invention is characterized in that the precursor polymer is obtained by thermal polymerization of a borazine of formula (I) wherein: R1, R3, R4 and R5, identical or different, represent an alkyl, cycloalkyl or aryl group; and R2 represents a hydrogen atom or an alkyl, cycloalkyl or aryl group.

Abstract: The invention concerns a method for making boron nitride fibres by drawing a polymer precursor and treating with ceramics the polymer fibres obtained by drawing. The invention is characterized in that the precursor polymer is obtained by thermal polymerization of a borazine of formula (I) wherein: R1, R3, R4 and R5, identical or different, represent an alkyl, cycloalkyl or aryl group; and R2 represents a hydrogen atom or an alkyl, cycloalkyl or aryl group.

Abstract: A process for the production of a panel, of the honeycomb support type clad on opposite sides with a skin of carbon/carbon or carbon/ceramic composite. A honeycomb support is produced by pyrolysis of a carbon cloth pre-impregnated with a thermosetting resin. Skins are produced from carbon cloth pre-impregnated with a thermosetting resin. The support and the skins are assembled with a carbon cloth pre-impregnated with a thermosetting resin between them. The assembly is polymerized and then pyrolyzed. Finally, a chemical infiltration in vapor phase is carried out for densification and reinforcement of the bonding of the assembly. Used in the production of structures requiring very high dimensional stability, such as those used in outer space.