R. Wernet, A.G. Schunk, W. Baumann, H.-R. Paur, M. Seipenbusch

Journal of Aerosol Science, 2015, 84, 14-20

A molecular beam apparatus (MBA) with an implanted time of flight (tof) measurement cell was used for energy controlled fragmentation experiments on Pt agglomerates. Due to high vacuum conditions, drag forces and stagnation pressure in front of the impaction plate slowing down agglomerates were negligible. Thus, this set-up permitted a precise and convenient detection of the impact velocity of agglomerates. Results on the velocity measurement and the related degree of fragmentation are presented. The current results on fragmentation were compared to the work of Seipenbusch, Toneva, Peukert, and Weber (2007). This was motivated by the question whether the exceedance of the theoretical van der Waals binding energy found in the above-quoted work was caused by calculating the impact velocity with the commonly employed approach of Marple (v_impact = 0.85 × v_gas). The theoretical van der Waals binding energy was found to exceed the experimentally gained binding energy by the factor of 55.4, which was in good agreement with the comparable published work.