Method for treating a metal element with ion beam

A method for treating a metal element of a part, wherein the metal element has a thickness eM, the method comprising:

• subjecting a surface of said metal element to an ion beam so as to implant ions of the beam into an implantation area of the metal element, the implantation area having a thickness
• wherein the ions of the beam are selected from among the ions of the elements in the list consisting of boron (B), carbon (C), nitrogen (N), and oxygen (O),
• wherein an acceleration voltage for accelerating the ion beam is greater than or equal to 10 kV, the beam has a beam power of between 1 W and 10 kW, and said acceleration voltage and beam power as well as a dose of ions per unit of surface area are chosen to allow the implantation of ions from the beam into the implantation area with a thickness eI of between 0.05 μM and 5 μm, and to allow diffusion of ions into an implantation-diffusion area having a thickness eI+eD greater than eI and between 0.1 μm and 1000 μm;
• the temperature TZF of an area of the metal element being treated, situated under the implantation-diffusion area, is less than or equal to a threshold temperature TSD where TSD is a temperature at which the ions of the beam travel 50 nm in 100 seconds in the metal of said metal element.