Synthesis and characterization of Zirconia-Yttria nanoparticles in t'phase by sol-gel and spray drying

The synthesis of Zirconia-Yttria nanoparticles in phase t', non-transformable tetragonal phase of the zirconia, is important for the reinforcement of different ceramic matrixes with nanometric and submicronic structures, in order to enhance the mechanical resistance of the composite obtaining a better and homogeneus stress distribution. The objective of this research is to obtain the phase t' by sol-gel synthesis and spray drying of the gel suspension. The precursors used in this study were: zirconium oxychloride octa-hydrate and yttrium oxide which was dissolved in hydrochloric acid and water, after salts hydrolysis, the suspension subsequently undergo to spray drying and the obtained spherical nanostructured aggregates were calcined at 650 degrees C. Non transformable tetragonal composition employed was 7.5YSZ (7.5% mol YO1.5), according to the equilibrium diagram of ZrO2-YO1.5 system. The products obtained were characterized by XRD and SEM, verifying obtaining the phase t' and analyzing the microstructure of the obtained particles. From XRD results, it was determined that calcination temperature was enough for the obtention of the t' phase. Its results were compared with obtained by controlled precipitation route of the same composition at high temperatures.