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Binding of an oxide layer to a metal: The Case of Ti(101̅0)/TiO2(100)

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)4224-4233
Number of pages10
JournalJournal of Physical Chemistry C
Volume116
Issue number6
DOIs
Publication statusPublished - 16 Feb 2012

Abstract

We study the chemical nature of the bonding of an oxide layer to the parent metal. In order to disentangle chemical effects from strain/misfit, the Ti(101̄0)/TiO 2(100) interface has been chosen. We use the density functional pseudopotential method which gives good agreement with experiment for known properties of bulk and surface Ti and TiO 2. Two geometries, a film-like model (with free surface in the structure) and a bulk-like model (with no free surface in the structure), are used to simulate the interface, in each case with different terminations of Ti and TiO 2. For the single-oxygen interfaces, the interface energies obtained using these two models agree with each other; however, for the double-oxygen ones, the relative stability is quite different. The disturbance to the electronic structure is confined within a few atomic layers of the interface. The interfacial bonding is mainly ionic, and surprisingly, there is more charge transfer from Ti to O in the interface than in the bulk. In consequence, the Ti/TiO 2 interface has stronger binding than the bulk of either material. This helps to explain why the oxide forms a stable, protective layer on Ti and Ti alloys. © 2012 American Chemical Society.

    Research areas

  • TOTAL-ENERGY CALCULATIONS, WAVE BASIS-SET, TITANIUM-DIOXIDE, THERMAL-OXIDATION, 100 SURFACE, RUTILE, CORROSION, FILMS, MICROSCOPY, INTERFACES

ID: 11320902