Thermodynamics of ultra-thin oxide overgrowths on Al–Mg alloys: Role of interface energy

Abstract A thermodynamic model is developed to predict the ultra-thin crystalline oxide overgrowth due to dry, thermal oxidation of single crystalline 〈 AlMg 〉 alloy substrate with respect to various parameters. Along with the bulk Gibbs free energies, this model also took the alloy/oxide interface energies and oxide surface energies into consideration. The developed model was then compared with the amorphous oxide overgrowths on this alloy substrate. For all cases, stability of a particular oxide at lower oxide-film thicknesses is found to be due to its lower interface and surface energies. The model predictions are found to be at par with the experimental observations.