Phase Composition, Microstructure and Electrical Properties of Alumina-Zirconia Eutectic Composites

Oxide eutectic composites prepared by a directional solidification are noticeable for their good mechanical properties and high temperature stability in oxidizing environments. In this paper we study the influence of stabilizers (Y, Sc) on the phase composition, microstructure and electrical properties of Al2O3 - ZrO2 eutectic composites. At a hypereutectic composition of the melt, we have prepared the composites with tetragonal ZrO2, which possesses conductivities comparable to those of the composites containing cubic ZrO2. An addition of Sc2O3 improves the ionic conductivity of the Al2O3 - (Y2O3) ZrO2 eutectic composite at high temperatures. Both the microstructure and ionic conductivity do not change along the composite (grown at a constant growth rate).