Abstract
The packing fraction of ultrafine particles was estimated by computer simulation. In the simulation, it was assumed that particles, onec contacted with others on tentative places, keep the contact, and a function (Shake Off function) which selects either of expelling a particle from or fixing it to the tentative place was introduced. As a result of the simulation, the packing fractions by volume of cubic and spherical particles were 0.22-0.59 and 0.20-0.40, respectively. On the other hand, the observed values of the packing fraction of alumina particles in the fired compacts prepared by mixing alumina (mean value of diameters, 20nm) with a large quantity of forming agents and firing were in the range of the values obtained from the computer simulation.
