Sol-gel synthesis of Na+ beta-Al2O3 powders

Powders of general formula Na1+xAl11O17+x/2 with x=0, 0.2 and 0.57 have been obtained by hydrolysis and condensation of metal alkoxides. X-ray diffraction investigations showed the crystallization of β-alumina peaks at 1100 °C, confirmed by DTA/TG measurements. The same phase was revealed for pellets sintered in air at 1400 °C. Densities up to 97% of the theoretical value were reached. Electrical performances of pellets of x=0.2 and 0.57 compositions were investigated by Dielectric Analyzer (DEA) at various frequencies. The measured values confirmed the good conductivity and activation energy performances of the material.