Dislocations in ?-alumina electrolyte material

Abstract

β-alumina obtained from a number of sources and manufactured by different techniques has been examined in the electron microscope. Dislocations have been observed on the basal plane and the Burgers vector determined as\(b = a/3 \). The presence of this type of dislocation has been explained on the basis of the crystallographic structure ofβ-alumina. It is also predicted that the unit dislocation dissociates into two and four partials according to the energetically favourable reactions: $$\begin{gathered} \frac{a}{3} \to \frac{a}{6} + \frac{a}{6} \hfill \\ \frac{a}{3} \to \frac{a}{6} + \frac{a}{6} + \frac{a}{6} + \frac{a}{6} \hfill \\ \end{gathered} $$ . Experimental evidence has been obtained which shows the presence of dislocations separated into two and four partials inβ-alumina. Microscopic deformation has been shown to occur in thin crystals ofβ-alumina in the electron microscope, by the passage of large numbers of dislocations along basal slip planes.