Ab-initio calculations of hydrogen diffusion coefficient in monoclinic zirconia

Abstract : During the corrosion in primary water of zirconium, hydrogen from the water diffuses through the oxide. To better understand this process, we use Density Functional Theory with hybrid functionals to calculate the energetics of interstitial hydrogen ions in defect-free monoclinic zirconia. While there is only one stable site for hydride ions in zirconia, protons have four different sites. We calculate the migration paths and energies between insertion sites to obtain the diffusion coefficients of hydrogen. We find that protons diffuse orders of magnitude faster than hydride ions, proving that protons are responsible for diffusion of hydrogen in monoclinic zirconia.