The final platelet size appears to be little affected by the FAST process with the standard sintering cycle (FIGURE ). The microstructure remains fine for all samples; only the AP sample appears to have larger platelets than the other samples. For samples with zirconia addition, zirconia appears as particles clustered at the grain boundaries between the alumina platelets, especially at the triple grain boundaries. The distribution is rather homogeneous in the material with particles ranging from a few hundred nanometers to a few microns in diameter. Interestingly, all the samples retain their anisotropic texture with the addition of zirconia, with zirconia particles showing an elongated shape, with the shortest dimension along the compression axis of the FAST.