Patent ID: 7182980
Filing Date: 2007-02-27
Classification: C04B,C23C

Abstract:
1. A chemical vapor infiltration method for densifying at least one porous substrate having a central passage, the method comprising the steps of: placing one or more porous substrates inside an enclosure to define within the enclosure an inside volume formed essentially by the central passage of the substrate or the central passages of a plurality of substrates in alignment, and an outer volume formed essentially by the outside of the substrate(s); providing at least one leakage passage putting said volumes into communication with each other other than through the substrate(s); admitting into the enclosure a gas containing at least one gaseous precursor of a matrix material to be deposited within the pores of the substrate(s); channeling the gas towards a first one of the inside and outer volumes, said first volume being closed at an end opposite from the end where the gas is admitted; and carrying out the densification of said substrate(s) by causing the gas to flow inside the enclosure from the first volume to the other or second of the inside and outer volumes by diffusing through the pores of the substrate(s) and by passing through the or each leakage passage throughout the densification process and by extracting residual gas from the enclosure from the second volume in which: a maximum acceptable threshold value inside the first volume for the pressure of the gas or for the partial pressure of the precursor contained in the gas is defined; and the total leakage section of the leakage passage(s) is given a value lying between a minimum value such that the maximum pressure value is not exceeded before the end of the densification process, and a maximum value such that a pressure difference is established between the first volume and the second volume as from the beginning of the densification process.