Abstract:
This study investigates the application of centrifugal force for the compaction of metal
powder. Previous studies using the centrifugal force for manufacturing the green bodies were focused
on fine powders with narrow particle size distribution or binary mixtures. This study explores
the particle packing of multi-sized powder. Aluminum alloy powder with a particle size less than
100 μm and polymer binder were admixed and compacted in the centrifugal casting with ranging
magnitudes of centripetal acceleration. Three different centrifugal forces were tested: 700, 1800,
and 3700 G. The microstructure of the green bodies was then observed on the SEM micrographs.
The obtained green bodies had high packing densities ranging from 62 to 69%. The packing density
and median particle size increase at the positions further away from the center of rotation of the centrifuge
with an increase of centrifugal force. The effect of centrifugal force on the segregation of
particles was investigated through the quasi-binary segregation index. The segregation phenomena
was not observed at 700 G, but clear particle segregation was found at higher centrifugal forces.
The increase of the centrifugal force resulted in higher segregation with finer particles moving to
the inner part of the spinning mold, with a significant change in the size of particles located closer to
the center of rotation. Overall, the centrifugal process was found to produce highly compacted green
bodies while yielding a segregation effect due to wide particle size distribution.