  The porosity of uniaxially compacted cohesive powders depends on the applied
stress (including gravity). The case, where these stresses are weak, is
considered. The compaction results in a porosity which is a function of
sliding, rolling and torsion friction. By contact dynamics simulations it is
shown that the influences of contact torques (static rolling and torsion
friction) on the porosity are significant and approximately additive. The
relevance for nano-powder pressure sintering is discussed.
