Forming beta-alumina bodies by electrophoresis from suspension - for use as solid electrolyte in electric energy sources

Bodies are formed from beta-Al2O3 by (1) preparing a suspension of beta-Al2O3 particles (most of them having a dia. of 1-2 u) in an organic liq. having a dielectric constant of 12-24 at 25 degrees C (pref. n-amyl alcohol, epsilon = 13.9); (2) electrophoretically depositing beta-Al2O3 particles to form a dense deposit on an electrode in a d.c. electric field of 100-10000 V/cm (pref. 1980 V/cm); (3) drying the deposit (pref. air-drying for 24 h); (4) removing the deposit from the electrode and sintering in an oxygen-contg. atmos. at 1700-1825 degrees C (pref. 1800 degrees C). The beta-Al2O3 bodies are used as a solid electrolyte in sources of electric energy, such as high-energy batteries contg. a Na anode and S cathode working at elevated temps. (such that both Na and S are in the liquid state). The prodn. of beta-Al2O3 bodies described above is simpler than the known methods, and the reproducibility is good.