Crystallizability and sinterability of a precursor prepared by oxalate method in ethanol solution

Abstract

A precursor of yttria-stabilized zirconia (YSZ) powder was prepared by the oxalate method in ethanol solution. The crystallizability and sinterability of the precursor were studied. The crystallizability of the precursor depends on preparation conditions, especially acidity. The final acidity of the solution from which the precursor is produced and the temperature at which the precursor is calcined can strongly influence the crystalline phase composition of the resultant powder, and can, in turn, limit the ability of a sintering compact to reach high density. The YSZ powder which results from calcining the precursor without milling the calcined powder for a long time, may be a less-agglomerated powder with a crystallite size of about 9 nm and a specific surface area of 46.3 m²g⁻¹. A full tetragonal zirconia polycrystal with 99% theoretical density can be obtained from the highly reactive powder by simple cold-pressing followed by pressureless sintering in air at temperatures as low as 1300 °C.