A METHOD OF DENSIFYING POROUS SUBSTRATES BY CHEMICAL VAPOR INFILTRATION OF SILICON CARBIDE

摘要

A reaction gas containing methyltrichlorosilane (MTS) and hydrogen is injected into the infiltration chamber (30) in which the substrate is placed andwhere predetermined infiltration temperature and pre ssure conditions obtain. Thegas entering the infiltration chamber is preheat ed (by plates 46) so as to bring it up to temperature before coming into contact with the substrate. The residual g as containing the remainder of the reaction gas together with gaseous reaction products is extracted from the chamber. Infiltration is performed at a tempe rature lying in the range 960.degree.C to 1050.degree.C, and preferably in the rang e 1000.degree.C to 1030.degree.C, under a total pressure of not more than 15 kPa, and preferably equal to 7 kP a to12 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 in ert gas (via 70).