First-principles study of hydrogen diffusion in α-Al 2O3 and liquid alumina
2004 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 69, no 2, 243021-243026 p.Article in journal (Refereed) Published
We have studied the energetics and mobility of neutral hydrogen in alumina Al2O3 using ab initio density-functional calculations. The mobility of hydrogen was studied in corundum (α-Al2O 3) as well as in liquid alumina. Using both static as well as molecular-dynamics calculations, and applying classical transition state theory, we derive the temperature-dependent diffusivity of hydrogen in α-Al 2O3 as D(T)=(21.7 × 10-8 m 2/s)exp(-1.24 eV/kT). The corresponding diffusivity of hydrogen in liquid/amorphous alumina, derived directly from ab initio molecular dynamics calculations, is D(T)=(8.71 × 10-7 m2/s)exp(-0.91 eV/kT). The computed diffusivity compares very well to experimental data. We conclude that diffusion of neutral hydrogen through the bulk of alumina is a good approximation of the mechanism for hydrogen mobility in corrosion scales. The representation of grain-boundary structures by amorphous alumina is, probably, realistic at higher temperatures.
Place, publisher, year, edition, pages
2004. Vol. 69, no 2, 243021-243026 p.
aluminum oxide, hydrogen, ab initio calculation, article, corrosion, density functional theory, diffusion, energy transfer, molecular dynamics, temperature dependence
IdentifiersURN: urn:nbn:se:kth:diva-157786ScopusID: 2-s2.0-1442288069OAI: oai:DiVA.org:kth-157786DiVA: diva2:771858
QC 201412152014-12-152014-12-152014-12-15Bibliographically approved