PAC characterization of Gd and Y doped nanostructured zirconia solid solutions

MARÍA C. CARACOCHE, JORGE A. MARTÍNEZ, ALBERTO F. PASQUEVICH, PATRICIA C. RIVAS, ELISABETH DJURADO AND FLORENCE BOULC´H

PHYSICA B - CONDENSED MATTER

Año: 2007 vol. 389 p. 98 - 102

0921-4526

A perturbed angular correlation (PAC) study as a function of temperature has been carried out on spray pyrolysis-derived powders and compacts of 2.5 mol% Y2O3–ZrO2 and 2mol% Gd2O3–ZrO2 nanostructured tetragonal zirconias. The powders undergo the ordinary thermal transformation between the two known defective t0- and t- regular t-tetragonal forms and also a partial and irreversible change to an ordered cubic configuration. The dynamical nature of the t0-form leads to an activation energy of about 0.15 eV for the oxygen vacancies movement. The as-obtained compacts do not exhibit any known cubic nanostructure but some additional contributions. In both of them a hyperfine component assigned to the orthorhombic phase is determined. In the smaller cation Y doped ceramic a small amount of monoclinic phase reflects an incomplete stabilization