New result in surface segregation of Ni-Cu binary alloys

We present for the first time experimental evidence for solute Ni segregation to the surface in Ni-Cu alloys where it has been generally believed that Cu atoms always segregate to the surface in agreement with various theories. A new insight is needed in surface segregation in order to account for our observation of Ni segregation in ${\mathrm{Ni}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Cu}}_{\mathrm{x}}$ alloys where x is in a range 0.84 to 1.0.