Effects of variable aspect ratio inclusions on the electrical impedance of an alumina zirconia composite at intermediate temperatures

A series of alumina–yttria-stabilized zirconia composites containing either a high aspect ratio (5 and 30 mol%) hexagonal platelet alumina or an alumina low aspect ratio (5 and 30 mol%) spherical particulate was used to determine the effect of the aspect ratio on the temperature-dependent impedance of the composite material. The highest impedance across the temperature range of 373–1073 K is attributed to the grain boundary of the hexagonal platelet second phase in this alumina zirconia composite.