(V) INVITED: Full first-principles calculation of oxygen self-diffusion in ceramic oxides

Wednesday, September 15, 2021: 10:00 AM
225 (America's Center)
Prof. Ying Chen , School of Engineering, Tohoku University, Sendai, Japan
Dr. Hubin Luo , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, China
Dr. Lei Wang , University of Science and Technology Beijing, Beijing, China
Prof. Tetsuo Mohri , Institute for Materials Research, Tohoku University, Sendai, Japan
The diffusion of oxygen in ceramic oxides is an essential issue in high temperature properties of ceramic materials. According to the atomistic theory of diffusion, the self-diffusion coefficient can be calculated from the integration of the kinetic factors (atom jump frequency and activation energy), the structural factors (correlation factor and atom jump distance in crystal) and the thermodynamic factor (vacancies concentration). The present work attempted a full first-principles calculation of the self-diffusion coefficient combining the electronic structures, phonon vibration spectrum and transition state theory (TST), incorporating charged vacancy effect and oxygen partial pressure effect, aiming at not only obtaining the diffusion property, but also the thermodynamic properties, phase transformation feature, and further providing a criteria of the real time scale for further study on kinetics. Zirconia is a typical ceramic oxide with three phases spanned a large temperature range with two phase transformations between the cubic-tetragonal (2650K) and the tetragonal-monoclinic (1478K) structure. The details of the methods and results will be presented.