Lead segregation at clean and oxygen-covered surfaces of A1-0.01%Pb solid solution

Abstract

Abstract The surface composition of Al-0.01at%Pb solid solution was studied between 300 and 700 K using low-energy Auger electron spectroscopy. Lead segregates strongly at the clean surfaces of this alloy ( X s = 0.55 at equilibrium), while above ∼ 550 K evaporation effects become dominant. Pre-adsorbed oxygen retards the segregation, but eventually, being more surface-active on Al, Pb atoms displace a large fraction of the surface oxygen. Thermodynamic aspects of the observed phenomena are discussed.