Alumina-based nanocomposites obtained by doping with inorganic salt solutions: Application to immiscible and reactive systems

Doping of commercial alumina nanopowders by using aqueous solutions of metal salts was exploited to prepare alumina-based nanocomposites. The same procedure was applied to produce a composite made of immiscible phases, that is an alumina–zirconia material, by doping an α-alumina powder with a zirconium chloride solution, as well as to produce an alumina–YAG (yttrium aluminium garnet) system by doping alumina with a yttrium chloride solution and promoting YAG formation by solid-state reaction at high temperature. For this latter case, the difference in reactivity between two commercial powders, one made of transition alumina, the other of pure α-phase, was investigated in terms of phase evolution and purity. In all cases natural sintering was performed to develop dense bodies.