Abstract: The effcct of bimodal partiele size distribution on the compact cfficiency and sintering behavior ofsubmicron-sized alumina powder was investigated For two types of submicroll alumina powders with sizeratio of about 2, collsidcrably lligller compact densitics, as compared to their individuaJs, were obtainedwhen mixed in proper volumc ratios. In the casc of 33% fine particls in the mixed powder, the relativegreen density of abovc 72% was achieved by pressure filtration. Different consolidation techniqucs, namely pressure filtration and drying press, were found to yield compacts with different properties. Green compacts by pressure filtration, which had higher density, narrower pore size distribution and smaller mean pore size than those by dry-pressing, can be sintered to theoretical density with fine microstructure at relatively low temperature. The sintering behavior and the microstructure developed for the compacts by different compaction techniques were discussed with newly developed theory of sintering thermodynamics.

Key words: A1₂O₃, bimodal particle sizc distribution, pressure filtration, sintering behavour