Preparation of dense ultra-fine grain barium titanate-based ceramics

Hydrothermal BaTiO/sub 3/ with 3-5 wt.% Bi/sub 2/O/sub 3/ was sintered to very high densities at 850 degrees C. New results on the effect of lower concentrations of Bi/sub 2/O/sub 3/ on the densification and the dielectric properties of the BaTiO/sub 3/ ceramic are discussed in the present work. As an expansion of the previous work, hydrothermal Sr/sub 0.2/Ba/sub 0.8/TiO/sub 3/ was sintered with 0-5 wt.% Bi/sub 2/O/sub 3/ between 850 and 1250 degrees C. When 5 wt.% Bi/sub 2/O/sub 3/ was added, the powder compacts sintered to a bulk density of greater than 5.2 gm/cm/sup 3/, at 950 degrees C. The room-temperature dielectric constant of this ceramic was 1500, and the K vs. T plot followed the Z5U industrial specification.<
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