Effect of different precipitants on the formation of ultrafine 3 mol% yttrium-stabilized zirconia nanopowders by reverse precipitation

Abstract

This study proposes a simple method for preparing highly dispersed ultrafine 3 mol% yttrium-stabilized zirconia nanopowders (3YSZ NPs), which provide high-quality powders for use in high-performance ceramics. First, 3YSZ NPs were prepared using a reverse precipitation method with different precipitants: NaOH, NH3·H2O and (NH3)2CO3. The thermal decomposition, phase evolution, morphology and chemical composition of the precursor particles and 3YSZ NPs were analysed. The effects of precipitant and reaction conditions on 3YSZ NPs were systematically studied. The results show that there are differences in the mechanism of powder synthesis using the co-precipitation method among the three precipitants. In addition, ultrafine 3YSZ NPs with minimum agglomeration and high sphericity can be prepared using NaOH. Y3+ and ZrO2+ cannot coprecipitate in solution according to the designed molar ratio in the NH3·H2O and (NH4)2CO3 methods. Considering agglomeration, crystallinity and elemental distribution, NaOH is the best precipitant. The prepared zirconia powder exhibits high crystallinity, good dispersion, a narrow particle size distribution and a tetragonal phase structure. By investigating the effects of calcination temperature, titration end point pH and NaOH concentration, 3YSZ NPs with an average particle size of 22.29–38.94 nm are obtained.