Characterization of the densification of alumina by multiple small-angle neutron scattering

Multiple small-angle neutron scattering was used to follow the evolution of the pore-size distribution in α-Al₂O₃ through the intermediate and final stages of sintering. This new technique enables the study of microstructure in the 0.08–10 μm size regime, which is the size range of importance for many materials systems, without needing to increase the resolution of currently available small-angle scattering instruments. The microstructure evolution results indicate a nearly constant effective pore radius for the alumina throughout the intermediate sintering stage, ranging from 0.19 μm at 54% of theoretical density to 0.17 μm at 79% dense. As the alumina densifies further, there is a transition region after which the effective pore radius grows rapidly to ≥0.6 μm at 97.5% dense.