β"-Al_2O_3の焼結特性と微構造に及ぼすZrO_2添加の影響

概要

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The Na-β"-Al_2O_3 electrolyte possessing high sodium ion conductivity is a candidate material for secondary batteries and thermo-electric converters. Sintered courpacts of β"-Al_2O_3 containing 0-10 vol% of ZrO_2 were made from calcined powder consisting of β"-Al_2O_3 and β-Al_2O_3. The effects of the ZrO_2 addition on the normalized index f(β") and microstructure of the sintered compacts were investigate, and the improvement of the density and normalized index was observed. It is therefore suggested that the ZrO_2 addition to β"-Al_2O_3 accelerates diffusion of the materials. The small amount of ZrO_2 is dissolved into the liquid which is generated during heat treatment. The dissolution ability or surface tension of that liquid appears to be influenced by the dissolution of ZrO_2, leading to improved sintering characteristics. The addition of ZrO2 affects the microstructure, especially the grain growth of Al_2O_3. While abnormal grain growth of Al_2O_3 takes place in the case of 0.1 vol% of ZrO_2 addition, such abnormal grain growth is prevented by a 1 vol% of ZrO_2 addition. The concentration of Zr at the grain boundary, which decreases grain boundary mobility, was observed. The concentration of Zr is therefore considered to prevent abnormal grain growth.
社団法人日本セラミックス協会の論文
1998-08-01