Abstract
Compaction curves were studied by direct observation of internal structure of the compact made from spray-dried granules. Compaction curves have been widely believed to occur in three stages, compaction by granule rearrangement, compressive fracture of granules and compaction by primary particle rearrangement in each granule. However, the behavior was not observed directly. In this study, we tried to observe the internal structure of the compact for each stage. Some kinds of alumina granules were fabricated by spray drying with changing slurry conditions. The characteristics of granules were measured for relative density, shape, flowability, and compression strength. The green compacts were made from each granule with uni-axial pressing method. The compaction curves in uni-axial pressing were measured by compression testing machine from 0 to 100MPa. Observation result showed that granule rearrangement occurred in first stage. The granule fracture and rearrangement of primary particle in granule was started simultaneously in second stage.
