The synthesis of polycrystalline [formula omitted] ceramics from conventional precursor [formula omitted] powders

Abstract

H 3O +β″Al 2O 3, H 3O +/βAl 2O 3 and H 3O +β″/βAl 2O 3 /ZrO 2 ceramics of equiaxed, fine-grained microstructure were prepared by conventional synthesis techniques, gas-phase and vapour-phase ion exchange to the potassium form and field-assisted ion exchange in dilute HCl vapour to the hydronium form. The bend strength of the polycrystalline H 3O +β″Al 2O 3 and H 3O +β″/βAl 2O 3 was > 200 MPa. The conductivity of H 3O +β″Al 2O 3, H 3O +β″/βAl 2O 3 ZrO 2 was 8×10 −6, 2×10 −6 and 9×10 −7 (Ω cm) −1, respectively, at 25°C. The materials were demonstrated to perform in steam electrolysis cells at 100°C.