Investigations on the fracturing of nanoparticle agglomerates—first results

Abstract

The mechanical properties of nanoparticle agglomerates have been addressed in many studies. Agglomerates of nanoparticles grown by stochastic processes such as diffusion-limited cluster-cluster agglomeration represent fractal-like objects. These agglomerates are not in the most stable state, and delivering a certain minimum energy, i.e. the activation energy for restructuring, can induce rearrangement. However, in many applications of nanoparticles a high degree of dispersion in the carrier medium (gas or liquid) is desired. Thus, the fragmentation of the aggregates down to the primary particles would be optimal. Depending on the production process, the bond strength between the primary particles will exhibit a distribution that may range from weak van der Waals bonds to strong solid state necking. In the present study, the degree of fracturing as indicated by image analysis of electron micrographs from impacted agglomerates of nanoparticles of Ag and TiO2 was investigated. The influence of kinetic energy on fracturing was studied.