Particle break-up upon impactionThe inertial impaction of nanosize agglomerates was investigated. The study focused on two processes that occur commonly simultaneously during the impaction of the agglomerate; bounce and fragmentation. The main objective was to study how different parameters affected these processes. The parameters that were considered included the impaction velocity, agglomerate properties, such as the composition and primary particle size, and impaction surface material.
The agglomerate properties had an effect on their impaction behavior. For example, the bounced fraction decreased but the fragment size did not change notably as the primary particle size was decreased. Enhanced degree of sintering increased the fragment size due to stronger bonds between the primary particles. At the lowest impaction velocity, a considerable fraction of the agglomerates bounced without fragmentation at the lowest impaction velocity in most cases.
This work was a collaboration between PSI and University of Eastern Finland, Kuopio. The results have been reported in the PhD thesis of Mika Ihalainen: