Preparation and electrical characterization of ultra-fine powder scandia-stabilized zirconia

Ultrafine powders of scandia-stabilized zirconia (ScSZ) were prepared by the co-precipitation method, using ZrOCl2 and ScO2 as raw materials and NH3 center dot H2O as a precipitant. In this paper, the optimum process parameters were investigated. The pH of the reaction solution directly impacted the precursor structure, which further affected the obtained crystal forming. Many experiment methods of thermogravimetric analysis and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy (Raman), and nitrogen adsorption were employed to characterize the ScSZ powder. The structure transition mechanism from cubic to rhombohedral was discussed. In addition, the electrical conductivity of the powders was also studied after dry-pressing and calcining. The results showed that the structure of ScSZ with complete crystal surface belonged to the cubic phase. The crystallite sizes of the powders prepared are about 60-80 nm, meet the conditions of (D-90-D-10)/2D(50)<= 1, and exhibited the good flow properties. The electrical conductivity was more than 190 mS/cm in air measured at 850 degrees C.