Compaction mechanisms of ultrafine SiC powders

The compaction of ultrafine SiC powders with different amounts of excess Si has been studied using cold uniaxial pressures between 10 3 and 10 8 Pa. The density range investigated covered, due to the extremely low as-received density of the powders (0.7%–1.0% theoretical density), more than one order of magnitude. A simple powder density versus applied pressure correlation with only one parameter was established for a large pressure range (up to 5 decades). The parameter depends on the die material and the particle diameter of the powders. A first attempt to explain the compaction process is given.