Today, the importance of industrial mass production of nano-scaled high quality products and specialty chemicals via pyrolysis or precipitation processes increased continuously. For application, the product properties are specified by particle characteristics such as size, morphology, abrasion resistance, specific surface and tendency to agglomerate which depends on the physicochemical properties of the particles as well as on the process parameters during synthesis and the following drying step. However, in most cases, nanosized particles aggregate during the growth phase forming secondary particles with sizes in the order of micrometers. Based on the variation of significant processing and formulation parameters during a silica semi-batch precipitation process, the primary and secondary aggregate formation, the resulting aggregate structure and their effect on the micromechanical properties and the dispersibility are investigated. The deformation and fracture behavior is characterized via nanoindentation techniques. Based on spherical sol-gel produced silica model aggregates, general models for the description of the micromechanical aggregate properties are derived. With respect to aggregates composed of particles in the nanometer size range, the effect of the particle-particle interactions on the micromechanical aggregate properties is presented by simulating the nanoindentation measurement of single aggregates using the “discrete element method” (DEM).weiterlesen