ABSTRACT
High-resolution electron microscope images are presented of a stabilized anion-excess zirconia alloy (nominally Ta2Zr8O21) which under electron irradiation undergoes in-situ reduction by the carbon of the electron-microscope support grid. The local oxygen concentration may be related directly to the distance between the modulation fringes which characterize this zirconia-tantala alloy, and the transport of oxygen to the surface of the alloy grains is observed as the fringes move over a period of tens of minutes. Micrographs are presented with examples of the modulation fringes both before and after reduction, and some of the mechanisms suggested whereby the crystals might afterwards relax while maintaining the continuity of the fringes throughout.
