Mechanochemical dehydration and crystallization of supersaturated zirconia–alumina composite nano powders

Zirconia/alumina composites are a family of structural ceramics with excellent mechanical properties. In order to improve the engineering reliability of this kind of composites, the uniform spatial distribution of the two phases is necessary. One of the effective methods to achieve this goal is to synthesize uniform zirconia–alumina composite nano powders. Here, we report mechanochemical synthesis of zirconia–alumina composite nano powders, in which dehydration and crystallization of Zr–Y–Al hydroxide can be achieved under milling conditions, leading to the formation of the tetragonal zirconia phase with supersaturated Al³⁺. The mechanochemically synthesized powders have the uniform element distribution and a fine primary crystallite size of around 11 nm. After sintering at 1400°C, t-ZrO₂/α-Al₂O₃ composite with the uniform phase distribution and grain size distribution could be obtained. To uncover the full benefits of these supersaturated composite powders in ceramic processing, future work could be done to break up the deagglomerations and improve the sinterability of the mechanochemically synthesized zirconia/alumina powders.