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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 f

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.

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A self-regulating reactive chemical vapor deposition (RCVD) process for producing a protective passivation overlayer upon individual carbon filaments in a multi-filament strand that includes the steps of placing one or more multi-filament strands of carbon in a reaction chamber, exposing the strands

A self-regulating reactive chemical vapor deposition (RCVD) process for producing a protective passivation overlayer upon individual carbon filaments in a multi-filament strand that includes the steps of placing one or more multi-filament strands of carbon in a reaction chamber, exposing the strands in the chamber to a carbon-free gas mixture containing hydrogen and a volatile compound which is capable of reacting with each carbon filament to form a carbide passivation overlayer on said filament, maintaining the total pressure within the reaction chamber at about atmospheric pressure, heating the strands to a desired reaction temperature at which the gas phase of the volatile compound reacts with each filament to form a thin homogeneous carbide passivation overlayer over the filament surface, said reaction temperature being below the temperature at which the gas phase reacts to form brittle crystals on said filaments, controlling the time that the strands are exposed to the gas mixture to prevent carbon from diffusing through the protective passivation overlayer and further reacting with the gas mixture so that each filament retains substantially its original characteristics.