Compaction of Alumina Powder with a Fugitive Liquid

Cold compaction behavior of several alumina powders of grain sizes between 5 and 0.05 μm average diameter was studied, both with and without a mixture of binder and lubricant (10 vol% epoxy resin). The compaction data, obtained up to 30,000 psi, were analyzed by Cooper and Eaton's equation [V*=a1 exp (‐k1/P)+]a2 exp (‐k2/P)], which indicated that the fractional volume compaction (V*) at pressure (P) depends on the particle size, shape, and most likely on the particle size distribution in the powder compacts, confirming the findings of Leiser and Whittemore. Addition of a binder‐lubricant to alumina affected primarily the values of the a coefficients and the possible final compact densities, whereas the values of the pressure coefficients k remained approximately constant, indicating that the pressure coefficients for the pore‐filling process were not affected by the presence of a lubricant.