PREPARATION AND CHARACTERIZATION OF ALUMINA-DOPED POWDERS FOR THE DESIGN OF MULTI-PHASIC NANO-MICROCOMPOSITES

The composite powders 90 vol.% Al2O3–5 vol.% YAG–5 vol.% ZrO2 were produced by doping commercial alumina powders with zirconium and yttrium chloride aqueous solutions. Both a nanocrystalline transition alumina and a pure α-phase powder were used as starting materials. The obtained materials were characterized by DTA-TG, XRD and dilatometric analyses and compared to the respective biphasic systems developed by the same procedure. Pressureless sintering at 1500 °C for 3 h was able to consolidate the doped powders in fully dense bodies, characterized by a very fine and homogeneous dispersion of the second phases into the micronic alumina matrix.