Effects of Microstructure on Mechanical Properties of Alumina Ceramics Produced by Spark Plasma Sintering

概要

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An ultrafine <I>α</I>-alumina powder was consolidated by spark plasma sintering (SPS) and the effect of microstructure on mechanical properties of the sintered compact was examined. The density and bending strength of sintered compact increased with sintering temperature and indicated the maximum value at 1573 K. In the temperature range higher than 1573 K, however, these properties decreased with the increase of sintering temperature. The changes of these properties were clarified by microstructural analysis using transmission electron microscope. It was indicated that the grain growth was fairly encouraged in the consolidation of alumina powder when the powder was consolidated at a sintering temperature higher than 1573 K. On the grain growth process, many fine pores occurred in the grains and/or on the grain boundaries. Further, the bending strength decreased remarkably so that larger pores existed on the grain boundaries at 1773 K.