Method for impregnation of a fibrous preform and device for implementation of the said method

1. A method of impregnating a fiber preform with an impregnation composition, the method comprising:

a) applying a liquid on a structure, the structure comprising:

a chamber in which a fiber preform for impregnating is present, the chamber being defined between a rigid support on which the fiber preform is placed and a wall, the wall having a face situated facing the fiber preform; and

an impregnation composition, for impregnating the fiber preform, the impregnation composition being present in the chamber;

the liquid being applied against the wall on its side opposite from the chamber, the wall being sufficient rigid so that its face situated facing the fiber preform conserves its shape and avoid being deformed during the application of the liquid, the applied liquid enabling sufficient pressure to be created to move the wall towards the rigid support and impregnate the fiber preform with the impregnation composition.

2. A method according to claim 1 , wherein, prior to step a), the method further comprises injecting the impregnation composition into the chamber.

3. A method according to claim 2 , wherein the impregnation composition is injected into the chamber after placing the fiber preform on the support, and wherein the impregnation composition is injected between the fiber preform and the wall.

4. A method according to claim 1 , wherein, prior to applying the liquid, the impregnation composition is superposed on the fiber preform over at least half of a length of the fiber preform.

5. A method according to claim 1 , wherein the structure also includes an impermeable membrane covering the wall, and wherein the wall is situated between the chamber and the impermeable membrane, and wherein the liquid is applied against the impermeable membrane on its side opposite from the chamber.

6. A method of fabricating a part comprising a fiber preform densified by a matrix, the method comprising:

b) densifying a fiber preform that has been impregnated by an impregnation composition that is a densification matrix precursor in order to obtain a part comprising a fiber preform densified by a matrix, the impregnated preform being obtained by performing a method according to claim 1 .

7. A method according to claim 6 , wherein the densification is performed while maintaining the pressure exerted by the wall on the impregnated preform as a result of the application of the liquid.

8. A method according to claim 6 , wherein the part constitutes a turbine engine blade.

9. A device for performing a method according to claim 1 , the device comprising:

a structure including a chamber defined between a rigid support and a wall, the wall having a face situated facing the rigid support, the chamber defining an internal volume in which a fiber preform impregnated by a matrix precursor impregnation composition is to be present, the chamber being configured to be subjected to heat treatment for the purpose of densifying the fiber preform; and

a liquid injection device configured to apply a liquid against the wall on its side opposite from the chamber;

the device being configured so that the application of the liquid against the wall on its side opposite from the chamber does not change the shape of the face of the wall situated facing the rigid support and generates sufficient pressure on the wall to move it towards the support and reduce the internal volume of the chamber.

10. A device according to claim 9 , wherein the structure further includes an impermeable membrane covering the wall, and wherein the wall is situated between the chamber and the impermeable membrane, and wherein the liquid injection device is configured to apply the liquid against the impermeable membrane on its side opposite from the chamber.

11. A device according to claim 9 , further comprising a heater member configured to perform heat treatment on the impregnation composition enabling the fiber preform to be densified.