**Figure 6.**

*Atomic force microscopy images of the valley-ridges pattern formed in the interdendritic region because of sputtering.*

**Figure 6** shows atomic force microscopy images of the interdendritic region to establish the origin of the sputtering inhomogeneity. Experimental evidence provided by MFA images (**Figure 6**) of the interdendritic region shows that the valleys and ridges regular pattern was formed as a sputtering result, this pattern regularity is very similar to the phases alternation that forms the Ni(Si)-Ni3Si-monoclinic regular eutectic. Therefore, it is hypothesized that one of the phases was preferentially sputtering and that this preferential sputtering is promoted by the chemical difference in composition between the two phases.

The sputtering yield of each phase that forms the Ni(Si)-Ni3Si-monoclinic regular eutectic was calculated using SRIM 2013 code [14]. **Table 1** shows the results of the sputtering yield simulation at the above-mentioned irradiation conditions.

Simulation results indicate that the terminal phase Ni(Si) has the highest sputtering yield. This means that this phase is the one that underwent the greatest sputtering under the irradiation conditions employed and consequently gives rise to the valleys formation observed in the atomic force microscopy images analyzed.

In addition, scanning electron microscopy images of the interdendritic region, **Figure 7**, show the same valley-ridges pattern, it should be remembered that the field depth of this microscopy is limited, however, the pattern characteristics are clearly observed.

