Density functional theory based indicators to predict the corrosion inhibition potentials of ceramic oxides in harsh corrosive media

Abstract

Coating metal surfaces with ceramic oxides is an experimentally established technique to curb the corrosion of metals. Herein, we used periodic spin-polarized density functional theory (DFT) to study the ceramic oxides Al₂O₃, TiO₂, HfO₂ and ZrO₂ for their corrosion-inhibition potentials under different harsh corrosive conditions. The adsorption of corrosive atoms on ceramic oxide surfaces is analyzed using DFT-computed indicators such as binding energies, Bader charges, projected density of states (pDOS), and geometric considerations. Adsorption is carried out on the energetically most favorable sites on the metal oxide slabs. Our DFT calculations predict the experimentally observed trends of the ceramic oxides reported in the literature in a chlorine-rich (saline) medium, which was ZrO₂ ∼ HfO₂ > TiO₂ > Al₂O₃. The computational model is then applied to test the performance of the ceramic oxides as protective layers in sulfur-rich and oxidizing harsh environments. Such a comprehensive DFT-based comparative analysis to predict the corrosion-inhibition potential of ceramic oxides is established for the first time to the best of our knowledge. This easy-to-use computational approach can be widely utilized to gain first-hand information on the anti-corrosion potentials of ceramic oxides and alloys without creating different corrosive conditions experimentally.