The present invention concerns a method for generating nanostructures in order to obtain in an area on the surface of a metal piece (10) a nanostructured layer of defined thickness, characterized in that it comprises: a step for projecting onto an impact point in the area of the surface of the piece (10) to be treated, for a given duration, at a given speed and at variable incidences at the same impact point, a given quantity of perfectly spherical balls (22) of given dimensions, reused continuously during the projection; repetition of the preceding step with a shift of the impact point so that the impact points as a group cover the entire surface of the piece to be treated; a step for treatment by diffusion of chemical compounds into the nanostructured layer generated during the step for implementing the method for generating nanostructures.