Effects of oxygen adsorption on the corrosion behavior of the Ti(0001) surface: a DFT investigation

Abstract

The interaction between O and α-Ti was studied by analyzing the adsorption energy, electronic structure and thermodynamic stability. The effect of adsorbed O on the Ti corrosion was explained from the perspective of electrochemical potential.

Influence of Ti Vacancy Defects on the Dissolution of O-Adsorbed Ti(0001) Surface: A First-Principles Study

“…The E ads of the O atom at the Fcc site (approximately 6.06 eV) exceeded that at the Hcp site (approximately 5.72 eV), indicating that the O atom was most stable at the Fcc site. This observation was consistent with previous studies [14,27]. Consequently, the Fcc site was selected for O atom adsorption in the subsequent calculations.…”

“…The dissolution activation energy of Ti metal serves as an electrochemical kinetic parameter, challenging to accurately estimate either through modeling or experiment means. In Figure 4, following our recent methodology [14], we simulate the surface structure post-Ti dissolution by constructing a Ti cavity at the center of the clean and O-adsorbed Ti(0001) surfaces. The dissolution activation energy was assessed using the Ti vacancy formation energy (E vac form ), which was required to create a Ti vacancy defect.…”

“…Furthermore, E vac form was positive, indicating that Ti atoms departed from the Ti surface endothermically. Considering the electrochemical corrosion mechanism [32], our recent research has shed light on the origin of this heat [14].…”

“…Wang et al employed this thermodynamic framework to explore the selective corrosion of the B 2 and B19 ′ phases of NiTi alloys, comparing the dissolution tendencies of Ni and Ti atoms [13]. In our recent work [14], we employed density functional theory (DFT) calculations to elucidate how oxygen (O) adsorption affected the corrosion behavior of α-Ti. Additionally, we investigated the impact of oxidation on the dissolution potential of Ti using the thermodynamic method proposed by Greeley and Nørskov.…”

“…In this investigation, we selected the most stable crystallographic surface, namely, the Ti(0001) surface [15], to delve deeper into the dissolution mechanism of α-Ti. Building upon our recent research [14], to ensure thorough consideration of the changes in various properties with varying oxygen coverage and to prevent overlooking crucial information, we meticulously examined the oxygen coverage of the Ti surface. We evaluated the influence of O adsorption on the electrochemical dissolution potential of α-Ti metal by introducing Ti vacancy defects on both clean and O-adsorbed Ti(0001) surfaces.…”