The effect of defects upon the stability of ceramic interfaces was investigated. It was shown that a reduced density of ions at the interface was essential for the stability of MgO(100)/MgO(100) twist grain boundaries. Triple-layer CeO2 on an Al2O3 substrate, with a 19.1 orientation, was shown to exhibit lower O-vacancy formation energies as compared with unsupported CeO2. These vacancies were also stabilized upon approaching the interfacial plane. The presence of the interface in this system was therefore expected to promote the migration of O from the interfacial plane to the surface. In the case of a CeO2 monolayer on Al2O3 with the same interfacial configuration, O vacancies at the interface were less stable than in the case of unsupported CeO2.

D.C.Sayle, T.X.T.Sayle, S.C.Parker, J.H.Harding, C.R.A.Catlow: Surface Science, 1995, 334, 170-8