Analyzing the Compaction of High-Porosity Microscopic Agglomerates

Abstract

Highly porous agglomerates of silica microspheres (1.5 µm diameter) with a porosity of 0.85, formed by random ballistic hit-and-stick deposition, were deformed inside a scanning electron microscope using the cantilever of an atomic force microscope. The applied force and structural deformations with single particle resolution could be obtained simultaneously. First results indicate that whole blocks of many particles move collectively upon compression. Within these blocks the relative positions of the particles remain fixed. This results in a discontinuous force–compression curve.