Concerning the Cu–Ni alloy, Ni segregates to the surface because of the first rule since Ni has the highest melting temperature compared to Cu, Δ T m,bulk = 371 K (∼21% of the highest melting point between Cu and Ni, i.e., Ni). Indeed, Δ T m,bulk = 313 K (∼15% of the highest melting point between Pt and Ni, i.e., Pt) is larger than 10% therefore, only the first rule applies. As Pt is totally miscible with Ni all over the composition range, the first rule applies, then Pt segregates to the surface since Pt has the highest melting temperature compared to Ni. suggested due to their definition therefore, there is no violation as claimed in the comment). In the case of total or even partial miscibility, both rules apply (of course, they cannot be applied simultaneously as Cui et al. (2) In the case of total immiscibility, only the second rule based on the surface energy applies.
Before those two rules are applied, the miscibility of the alloy has to be determined, and this can be done by using the well-known Hume–Rothery’s rules.
If not, the surface segregation will then be determined by the solid surface energy, promoting to the surface the element with the lowest surface energy (second rule). The first segregation rule we state in ref 1 is that the element with the highest bulk melting point will segregate to the surface if the difference between the bulk melting temperatures of the two elements is larger than 10% of the highest melting point. In this response, we provide irrefutable evidence that their own segregation rules are inexact and unable to explain the surface segregation observed in several bimetallic nanoalloys. claim that the segregation rules we proposed in our published paper (1) are questionable and therefore proposed two other segregation rules.
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