Synthesis and sintering behaviour of hydrothermally synthesised YTZP nanopowders for ion-conduction applications

The influence of hydrothermal synthesis parameters (pH, temperature, initial Zr concentration) on the chemical composition, crystalline structure, crystallite sizes and grain sizes of 4 mol% YTZP powders was investigated. Tetragonal, cubic, and monoclinic phases were formed as a function of the synthesis conditions. Tetragonal zirconia was formed as major phase at lower pH, in correlation with the synthesis parameters and precipitate chemical composition. Hydrothermal temperature increases the crystallization degree and crystallite sizes while decreasing particle sizes, particle sizes also decreasing with decreasing pH. The analysis of sintering curves revealed that a densification process takes place in the temperature range 800–1300 °C with a well-defined maximum around 1100 °C, leading to the formation of ceramic materials with fine equal grains. The dense sintered pellets obtained were used to study the oxygen transport properties in zirconia nanomaterials.