**5. Conclusion**

The microstructure changes induced by ion beam irradiation of the irradiated surface depend on the parameters associated with the ion beam, ion type, beam flux, beam energy, and irradiation time, as well as on the surface microstructure, mainly on the phase's chemical composition, the phases distribution on the surface, the surface defects present and the ion beam-surface interaction parameters, mainly the ion beam incidence angle and the mass ratio between target and the ion used to irradiate the material.

As a result of the ion beam—Surface interaction process, several sputtering mechanisms are activated, mainly the chemical one, giving rise to the preferential sputtering of one of the phases present on the surface, the terminal phase Ni(Si) was determined to be preferentially eroded, since it has the highest sputtering yield (see **Table 1**), also when comparing its average molecular weight with the atomic weight of Nickel it is observed that the difference between both is less than 10%, which promotes a greater energy transfer to this phase. On the other hand, it is known that there is a critical local angle of incidence of the ion beam that promotes the activation of the geometric sputtering process, the main characteristic of this geometric mechanism is that it has the potential to modify the topography generated as a result of the preferential erosion of a specific microstructural component, even in an extreme case to produce the smoothing of the surface under irradiation.

Finally, the degree of the changes induced on the irradiated surface are strongly linked to the complexity of the microstructure of the surface of the material used as a target, therefore, the use of sputtering as a tool to develop new materials is conditioned to the microstructural characteristics of the material to be used as target and to the type of ion employed.
