Temperature effects on rod-like zirconia particles. Morphology, degree of crystallinity and texture

Abstract

The paper reports data concerning zirconia samples obtained by coupling a first hydrolysis reaction of ZrCl 4 in solution at 100°C with subsequent treatments of the powders at higher temperatures (400–800°C). The products of the reactions are characterized by X-ray diffraction, scanning electron microscopy and N 2 adsorption. The samples appear to be composed, at any temperature, of pure baddelyite with a degree of crystallinity which increases with the temperature of preparation. Morphologically, the products have the shape of prismatic rods of variable dimensions. The rods are the result of sintering of the primary particles produced during the precipitation in solution. The general prismatic pattern of the rods is not affected by the temperature of calcination; conversely, the texture of the rods (i.e. the degree of hydration and aggregation of the primary particles) strongly depends on the temperature of the treatment. The nature of the interactions taking place between water and the solid particles, at different temperatures, is discussed.