The behaviour of two different nano-sized powders, SiO2 and Al2O3, has been
investigated. The properties of the powders are reported in Table I. The size
distributions of the powders as received are reported in Fig. 1. Analysis of data
shows that both the powders form relatively large agglomerates, with a Sauter
diameter of 250 and 190 nm for Al2O3 and SiO2 respectively. Typical aggregates
structures, obtained by using a scanning electron microscopy (SEM), are shown in
Fig. 2. Analysis of the pictures shows that both the powders form relatively large
aggregates even if those formed by SiO2 are more irregular.