The platelets of the Zt compositions were obtained from an adsorption of zirconia nanopowders partially stabilized in the tetragonal phase by 3 molar % yttrium (TZ-3Y-E, TOSOH) on the alumina platelets. In the case of the AP ng -Zt composition, the zirconia powder was added to the solution containing the alumina nano-particles and the precursors of the glass phase. For the AP-Zt powder, the zirconia powder was placed in water with a dispersant (Darvan 7NS, Vanderbilt Minerals LLC) under stirring for 15 min. The alumina platelets were then added to the solution and mixed for three hours with alumina media. Afterwards, the process is the same as for AP ng , i.e. freezing in liquid nitrogen followed by freeze-drying, heat treatment and de-agglomeration of the powder.