Diffusion limited crystallization and phase partitioning in ZrO2-metal oxide binary systems

Chemical routes to synthesize inorganics can start with solutions where multiple elements remain well mixed during liquid evaporation, precursor decomposition and crystallization. Because crystallization generally occurs at temperatures where diffusion is very limited, a single phase can crystallize with a greatly extended solid-solution that does not achieve its equilibrium phase assemblage until much higher temperatures where diffusion is no longer constrained. Partitioning at these higher temperatures can lead to unique microstructures such as the nano-composite illustrated here for a metastable Zr_(1–x)Al_xO_2–x/2 (x0.57) phase that partitions into a composite containing t-ZrO₂ grains and -Al₂O₃ plates.