Influence of the synthesis process on the properties of yttria stabilized zirconia powders obtained by the sol–gel method: Characterization and analysis of the samples thermal evolution

NADIA MAMANA; ANTONIO DÍAZ-PARRALEJO; ANGEL LUIS ORTIZ; FLORENTINO SÁNCHEZ-BAJO; RICARDO CARUSO

Buenos Aires

Simposio; 15 th International Symposium on Metastable, Amorphous and Nanostructured Materials; 2008

UBA-CONICET-CIDIDI

Yttria stabilized zirconia (YSZ) powders have been prepared by means of the sol–gel method using different processes. Zirconium n-propoxide (ZNP) was dissolved in n-propanol (PrOH) at pH 0.5 and 5. Different solutions were prepared with and without the presence of the acetic acid in the hydrolysis medium. Powders were obtained by gelificating and drying of the solutions at 100 ºC in air atmosphere. Pellets were prepared by uniaxial pressing of these powders at 200 MPa. The structure and microstructure of the samples were analyzed by X-ray diffraction and the morphology was observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). A porous characterization and specific surface area of the YSZ powders has been carried out by N2 adsorption at 77 K. The porosity of sinterized pellets was determiner by the Arquimedes method. The influence of the sol-gel synthesis process on the samples properties has been analyzed. The pH of the medium in which the hydrolysis of ZNP was performed has a strong influence on the microstructure, morphology and sintering process of the prepared samples. The powders prepared at different pH have different colors, morphology and crystalline structure. The use of acetic acid gives to compact samples with high residual porosity after the thermal treatment. On the other hand, the pellets prepared from the powders obtained at pH 5 present higher densification.