Synthesis of Yttria Stabilized Zirconia by sol–gel route: Influence of experimental parameters and large scale production

Abstract

This paper develops an advance in the field of new synthesis techniques for functional materials like Yttria Stabilized Zirconia (YSZ) used as sensors, thermal barriers or electrolytes for high-temperature fuel cells. In recent years, sol–gel routes were developed to prepare, by suitable chemical modifications, submicronic based materials with a controlled morphology, which conventional solid state chemistry paths are unable to provide. Wet chemistry methods provide interesting alternative routes because mixing of species occurs on the atomic scale. In this paper, ultrafine powders were prepared by a novel wet chemistry method based on the sol–gel process. One of the advantages of this method is to decrease the crystallization temperature in comparison to the conventional ones, allowing the synthesis of reactive powders with nanometric particles size. In this study, several processing parameters have been investigated (the hydrolysis ratio, the concentration of metallic precursors in the sol and the role of organic compounds and additives). Pure phases of YSZ were obtained and the characteristics of these powders investigated (crystallographic study, morphology, phase composition, etc.). Also, our optimised synthesis was applied to large scale elaboration by increasing the quantity of precursors. This study underlines the interest of the sol–gel process both to control the morphology of oxides and to prepare large amounts of high purity powders for an eventual industrialization process.