Abstract
The parameter c, reflecting the frictional and cohesive properties of binary powder mixture was obtained from the bottom pressure measurements. The effects of the particle diameter. ratio and the way of external pressure application upon c were studied.
In. all cases, c of the mixture deviates from the linear. line connecting the value of each component, although the parameter c approached to the linear line for the small diameter ratios. At low external pressure experiments, the deviation was positive. This deviation was, however, reversed when relatively high pressure was applied with preconsolidation.
These findings indicate that the interaction between fine and coarse particles, accordingly the state of aggregates is quite different depending on the applied external pressure. A part of these interactions was considered as due to the coarse-fine aggregates, which was confirmed by the relation of c to the loosely packed density.
Therefore, a care must be always taken in evaluating the flow or compressional properties, i.e., in measuring the frictional or cohesive properties of mixed powders and its effects on the state of aggregates, particularly in regard to the range of applied force.
