Zirconia powders obtained from zirconyl nitrate by precipitation with the varied concentration of the ammonium hydroxide

Phase stability and degradation of zirconia-based ceramics, which represents a very important industrial material, highly depend on the dispersity and structure of the raw powder materials. The aim of this research was to study the influence of the concentration of the precipitating agent (ammonia) on the agglomeration, morphology and crystallisation of zirconia particles during precipitation from zirconyl nitrate salt. By potentiometric titration, it was shown that precipitation with 1 M ammonia solution balances the processes of hydrolysis and precipitation. According to STA, XRD and PSD data crystallisation temperature decreases by 77°C when ammonia concentration is reduced from 0.5 to 0.2M resulting in the kinetic stabilisation of the tetragonal zirconia at 550°C. BET data showed that the highest specific surface area of the powders was obtained in the case of precipitation from 0.5 and 1M ammonium hydroxide solutions.