Abstract: Carbon bodies are heated in an oven under low pressure and while being swept with an inert gas, gaseous effluent containing elemental or compound sodium in sublimed form being continuously extracted from the oven via an effluent exhaust pipe. At least one sodium-neutralizing agent is injected into the effluent exhaust pipe immediately downstream from the outlet for exhausting gaseous effluent from the oven. The sodium-neutralizing agent is selected from carbon dioxide and steam, and it can be injected continuously into the flow of gaseous effluent.

Abstract: Carbon bodies are heated in an oven under low pressure and while being swept with an inert gas, gaseous effluent containing elemental or compound sodium in sublimed form being continuously extracted from the oven via an effluent exhaust pipe. At least one sodium-neutralizing agent is injected into the effluent exhaust pipe immediately downstream from the outlet for exhausting gaseous effluent from the oven. The sodium-neutralizing agent is selected from carbon dioxide and steam, and it can be injected continuously into the flow of gaseous effluent.

Abstract: A reaction gas containing methyltrichlorosilane (MTS) and hydrogen is injected into the infiltration chamber (30) in which the substrate is placed and where predetermined infiltration temperature and pressure conditions obtain. The gas entering the infiltration chamber is preheated (by plates 46) so as to bring it up to temperature before coming into contact with the substrate. The residual gas containing the remainder of the reaction gas together with gaseous reaction products is extracted from the chamber. Infiltration is performed at a temperature lying in the range 960.degree. C. to 1050.degree. C., and preferably in the range 1000.degree. C. to 1030.degree. C., under a total pressure of not more than 25 kPa, and preferably equal to 7 kPa to 12 kPa, and the concentration of silicon-containing species in the residual gas is lowered at the outlet from the infiltration chamber, e.g. by injecting an inert gas (via 70).

Abstract: The material is formed by a fibrous reinforcement constituted by a texture of carbon or silicon carbide fibers and a matrix deposited by chemical vapor infiltration through the porosity of the fibrous fabric and containing free carbon co-deposited with the zirconia, the weight proportion of free carbon co-deposited with the zirconia in the matrix being preferably between 0.1 and 10%. In comparison with pure or partly stabilized fritted zirconias, the composite zirconia according to the invention exhibits an improved tenacity, preservation of the mechanical strength and dimensional stability under high temperatures, as well as an improved density, without the introduction of the fibrous reinforcement reducing too excessively the properties of heat insulation and resistance to oxidation.