Method of making protective reinforcement for the leading edge of a blade

1. A method of making a reinforcement for protecting a blade comprising a leading edge, a trailing edge and two side faces, the method comprising:

depositing a metal coating on the leading edge by thermal spraying in compression so as to form a reinforcement in compression, and

prior to the thermal spraying in compression, forming at least one longitudinal groove in the blade on either side of the leading edge, with the metal coating being deposited in the grooves, the reinforcement being U-shaped and including a base extended by two side flanges situated respectively on each side face, each side flange presenting a profile that begins by tapering going towards the trailing edge and becomes thicker towards an end portion of the flange, the flanges presenting a first thickness in the grooves and a second thickness upstream from the grooves, the first thickness being larger than the second thickness.

2. The method according to claim 1 , wherein the metal coating is made of Ni, Al, or Ti, or of an alloy based on Ni, Co, Al, or Ti, or of cermet.

3. The method according to claim 1 , wherein the reinforcement has a thickness in a range of 0.5 mm to 20 mm.

4. The method according to claim 1 , further comprising depositing a bonding underlayer on the leading edge prior to the depositing of the metal coating.

5. The method according to claim 1 , further comprising fastening a metal foil onto the leading edge prior to the depositing of the metal coating.

6. The method according to claim 1 , wherein on a downstream side, each groove is defined by a step in each side face of the airfoil, the steps forming abutments for the reinforcement in an event of an impact and thus preventing the reinforcement from sliding on the airfoil.

7. The method according to claim 1 , wherein the blade further comprises a root and a tip, and the longitudinal groove extends in a length direction of the blade between the root and the tip.

8. The method according to claim 7 , wherein the groove follows a shape of the leading edge.

9. A blade comprising:

a leading edge, the leading edge being protected by a reinforcement formed by a metal coating deposited on the leading edge by thermal spraying in compression;

a trailing edge;

two side faces; and

at least one longitudinal groove on either side of the leading edge, the grooves being filled with the metal coating,

wherein the reinforcement is U-shaped and includes a base extended by two side flanges situated respectively on each side face, each side flange presenting a profile that begins by tapering going towards the trailing edge and becomes thicker towards an end portion of the flange, the flanges presenting a first thickness in the grooves and a second thickness upstream from the grooves, the first thickness being larger than the second thickness.

10. The blade according to claim 9 , the blade being made of organic matrix composite material.

11. The blade according to claim 10 , the blade being a blade of a turbine engine, a helicopter, or a propeller.

12. The blade according to claim 9 , wherein the metal coating is made of Ni, Al, or Ti, or of an alloy based on Ni, Co, Al, or Ti, or of cermet.

13. The blade according to claim 9 , wherein the reinforcement has a thickness in a range of 0.5 mm to 20 mm.

14. The blade according to claim 9 , wherein the blade further comprises a root and a tip, and the longitudinal groove extends in a length direction of the blade between the root and the tip.

15. The method according to claim 14 , wherein the groove follows a shape of the leading edge.