Fabrication of three-dimensionally close-packed aggregate of particles under mechanical vibration

A fabrication process for making three-dimensionally close-packed structures of SiO2-microparticles was proposed by utilizing external mechanical vibration. An experimental device was designed to make three-dimensional arrays through vibrating colloidal particles in suspension. The optimum condition for the vibration was examined to yield the most sufficient close-packed structures in their large dimensions. The experimental technique proposed in this study is efficient tool for eliminating defects undesirably induced and included in the particulate aggregates with close-packed structures. The microscopic processes of the formation of three-dimensionally ordered aggregates were also examined using the discrete element method (DEM). The experimental observations for the nucleation and the growth of close-packed structures associated with appropriate mechanical vibrations were well realized in the DEM simulation, suggesting the useful information on the efficient engineering fabrication of close-packed structures of particulate aggregate.