METHOD FOR CHEMICAL INFILTRATION IN THE GAS PHASE FOR THE DENSIFICATION OF POROUS SUBSTRATES WITH PYROLYTIC CARBON

摘要

One or more porous substrates (10) for densification are placed in an oven (12) with admission of a reacting gas phase through the inlet thereof, containing a gaseous precursor of pyrolytic carbon with at least one gaseous hydrocarbon C_xH_y in which x and y are whole numbers and x is such that 1 < x < 6, and a vector gas selected from methane and inert gases. The effluent gas, comprising residual components of the inlet gas phase and reaction products, of which hydrogen is extracted from the oven and recycled (circuit 80) to the inlet reaction gas phase at the oven inlet, a fraction at least of an extract gas flow from the effluent gas, containing reactant gas as a precursor to pyrolytic carbon, the recycling being carried out after removal of heavy hydrocarbons (process 40) contained in the effluent gas.