Co-precipitated synthesis of Al2O3–ZrO2 composite ceramic nanopowders by precipitant and drying method regulation: A systematic study

Abstract Uniform Al 2 O 3 –ZrO 2 composite ceramic nanopowders containing 13.1–25.5 wt% ZrO 2 were prepared by coprecipitation method using various precipitans (NH 4 HCO 3 , NH 3 ·H 2 O, and (NH 3 ) 2 CO 3 ) and drying methods (vacuum drying, spray drying, and freeze drying). The effects of precipitants and drying methods on Al 2 O 3 –ZrO 2 nanopowderswere were explored systematically by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive analysis (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The results showed that it is proper to use NH 4 HCO 3 as precipitant and freeze drying as drying method when taking into account extent of agglomeration, degree of crystallinity, and elements distribution of Al 2 O 3 –ZrO 2 ceramic nanopowders, which had a narrow particle size distribution concentrating on 30–60 nm with an average sphere diameter of 47 nm. Those findings are also elucidated at micro level to give insight into the underlying mechanism under various precipitants and dry methods. In addition, the moisture of the preparation of Al 2 O 3 –ZrO 2 nanopowders was first used to predict the extent of aggregation in the subsequent calcination process. In summary, these systematic works study the influence of two key factors on properties of Al 2 O 3 –ZrO 2 ceramic nanopowders and guide for the further research of high performance ceramics.