The objective of this work was to compare the sinterability, the
microstructures and the mechanical properties of Si3N4 ceramics with
additive mixtures based on yttrium oxide, Y2O3, and a mixed concentrate
of yttrium and rare earth oxides. The RE2O3 samples were prepared by a
two-step gas-pressure sintering process. No significant differences
between the samples have been found, thus demonstrating the potential
of this low cost alternative sinter additive.