Abstract
The influence of the size of coarse particles on packing and sintering behavior was investigated for mixtures consisting of a fine and a coarse alumina powders of which the average particle sizes were 0.52μm and from 2 to 12μm, respectively. In most mixing ratios, green compacts containing large coarse particles had high densities, large pore sizes and broad pore size distributions. For low volume fractions of fine particles, the densification of mixtures containing smaller coarse particles proceeded faster at any firing temperature. For high volume fractions of fine particles, the densification of mixtures containing small coarse particles proceeded slower at low firing temperatures, but proceeded faster at high firing temperatures. For mixtures containing small coarse particles, these facts are explained by the large inhibiting effect of the coarse particles on the densification of fine particles at low firing temperatures and by the large shrinkage of coarse particles at high firing temperatures.
