| 摘要 |
The substrate (30) is placed inside a housing (34) and is heated by direct electromagnetic coupling by means of an inductor (38) in order to set up a temperature gradient within the substrate so that the latter has a temperature higher in the portions remote from its exposed surfaces than on said exposed surfaces. A reactional gas phase precursor of the material to be infiltrated is introduced into the housing, formation of the precursor being enhanced in the portions of the substrate having the higher temperature. According to the invention, the substrate is comprised of a fibrous texture wherein the ratio rho r/ rho c between the transverse electrical resistivity and the longitudinal electrical resistivity is at least equal to 1.3 and the ratio lambda r/ lambda c between the transverse thermal conductivity and the longitudinal thermal conductivity is at the most equal to 0.9, and the substrate is situated entirely within the field produced by the inductor, the substrate and the inductor occupying positions which are fixed with respect to each other. Advantageously, the substrate is comprised of a needled fibrous structure having a volume proportion of fibers at least equal to 20 %.
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