The formula for surface composition of solid solution Al–Me (Zn, Sn, In) has been derived from the Gibbs's adsorption equation. Using the first-principles data of Al and Me surface energies, the values of adsorption x Me, and surface enrichment of alloy x Me/ N Me versus concentration in the bulk of alloy N Me, were calculated. The value of x Me/ N Me decreases in the order In–Sn–Zn in Al–Me alloy. The surface of Al–1 wt.% Sn alloy was analyzed with SIMS and Auger methods for Al and Sn both prior and post corrosion attack or anodic dissolution in Na 2SO 4. The maximum experimental magnitude of x Sn/ N Sn = 136 was found to be close to the theoretical one. A large diffusion zone was revealed in the near-surface layer of that alloy. The phenomena of ultra-high rate of atomic diffusion within surface layer at room temperature and high solubility of tin are discussed in terms of thermodynamic vacancy model.