| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sintered body excellent in Na-ion conductivity by controlling the content of Na-component in the vicinity of the outer surface and inner surface to be not more than that in the inside of the sintered body. SOLUTION: The suitable difference between the content of Na-component in the vicinity of the outer surface and inner surface of the β-alumina sintered body and the content of Na-component in the inside of the sintered body is not more than 0.5 part by weight. The content of Na-component in the vicinity of the surfaces is preferably controlled in the range that the relative density of the sintered body is not less than 97%. The mechanical strength of the sintered body is enhanced without lowering the Na-ion conductivity by adding at least one of zirconia or titania to β-alumina sintered body. A magnesia ceramic having a purity of >=99% is preferably used as a vessel for sintering. A bottomed cylindrical β-alumina sintered body having high relative density and mechanical strength and excellent in Na-ion conductivity is obtained by providing a vent or a space in the vessel for sintering and allowing a portion of vapor such as sodium oxide formed in the sintering process to flow out. |
