Preparation and characterization of textured polycrystalline Na and K-β″β-aluminas
Abstract Polycrystalline samples of Na, K-β″ β -aluminas with a c0-textured microstructure have been successfully produced. Very fine, high-aspect-ratio, freeze-dried powder was pressed into thin disks and sintered. The high degree of preferential orientation in the resultant ceramics was revealed by XRD and SEM examination. A significant difference of electric conductivity between directions perpendicular and parallel to the pressing direction was determined by ac impedance spectroscopy, i.e., 2.7×10−6Ω−1 cm−1 and 2.2×10−4Ω−1 cm−1 respectively at 25°C for K-β″ β -aluminas.