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 continuously coating a strand of continuous carbon filaments by means of a refractory carbide by reactive technique which includes the step of causing the strand to travel under mechanical tension with a hermetic enclosure, simultaneously, introducing into the said enclosure a carbon free gas mixture consisting of hydrogen and of a volatile compound of an element capable of forming a refractory carbide; and heating the reaction mixture consisting of the strand and the gas mixture under controlled conditions so that the formation of the carbide deposit on the filaments takes place by a chemical reaction between the carbon in the filaments and the gas mixture. Under these controlled conditions, the reaction is self-regulated to produce a thin homogenous passivation coating on each filament.

Abstract: A process for continuously coating a strand of continuous carbon filaments by means of a refractory carbide by reactive CVD deposition, which includes the step of causing the strand to travel under mechanical tension with a hermetic enclosure, simultaneously, introducing into the said enclosure a gas mixture consisting of hydrogen and of a volatile compound of an element capable of forming a refractory carbide; and heating the reaction mixture consisting of the strand and the gas mixture so that the formation of the carbide deposit on the filaments takes place by a chemical reaction between the carbon in these filaments and the gas mixture; and the reaction is self-regulated by the diffusion of carbon through the layer of carbide already formed.