Adsorption and diffusion behavior of oxygen atoms on Ti₃SiC₂ (0001) surface

Abstract

Ti3SiC2 is the most typical 312 MAX phase, which has attracted more attentions in many fields. In this paper, the (0001) plane of Ti3SiC2 was built. The adsorption energy and diffusion path of oxygen atom at different sites were calculated by first principles. There are three different adsorption sites for oxygen atom on Ti3SiC2 (0001) surface. By calculating the adsorption energy of the three adsorption sites, it was found that the adsorption energy of the oxygen atom at the center site is the lowest. The diffusion path of the oxygen atom was simulated and showed that oxygen atom located at the center of Ti-Si tetrahedron after the diffusion into the bulk phase. The effects of solid solution elements on the diffusion activation energy of oxygen atoms were calculated. suggesting that the solid solution of V, Mo and W will greatly increase the energy barrier, thus preventing the inward diffusion of oxygen atoms.