Segregation of Sn and Sb in a ternary Cu(1 0 0)SnSb alloy

Surface segregation studies of Sn and Sb in Cu(1 0 0)–0.14 at.% Sn–0.12 at.%Sb ternary alloy, have been done bymaking use of Auger Electron Spectroscopy. Themethod of Linear Temperature Ramp (LTR) was employed, whereby the sample was heated and cooled linearly at a constant rate. The positive heating rate showed both a kinetic segregation profile, as well as a narrowequilibrium segregation region, at higher temperatures. The equilibrium segregation profilewas extended by cooling the sample. Sn was first to segregate to the surface due to its higher diffusion coefficient, mainly from a smaller activation energy ESn. Sb, due to its higher segregation energy, eventually replaced Sn fromthe surface. The modified Darken model was used to simulate the profile yielding the following segregation parameters: Do(Sn) = 6.3 10 6 m2/s, Do(Sb) = 2.8 10 5 m2/s; ESn = 175.4 kJ/mol, ESb = 186.3 kJ/ mol; DG Sn ¼ 64:2 kJ=mol, DG Sb ¼ 84:3 kJ=mol; VCu–Sn = 3.4 kJ/mol, VCu–Sb = 15.9 kJ/mol and VSn–Sb = 5.4 kJ/mol.