Overall, our analysis suggests that

Overall, our analysis suggests that the densification of the vaterite compacts is controlled by localized deformation processes operating over three distinct length scales. At the scale of the pressing die, frictional forces and imperfections of the punch seem to favor the deformation of powder in the center of the compact. In turn, stress intensification at inter-agglomerate contacts promotes localized deformation of specific sites at the length scale of individual agglomerates. Eventually, the assembly of interconnected nanoparticles at the smallest length scale undergoes the actual deformation required for the macroscopic densification of the compact.