| Abstract [eng] |
Synthesis, Characterization and Analysis of Gadolinium Doped Ceria Gadolinium doped ceria (GDC) were obtained by sol-gel (SG) and sol-gel combustion (SGC) synthesis routes using two different complexing agents/fuels (glycerol (GL) and tartaric acid (TA)). The thermal behaviour of Gd-Ce-O precursor gels was investigated by TG-DSC measurements. X-ray diffraction (XRD) analysis was used for the characterization of phase purity and crystallinity of synthesized samples. It was determinated that synthesized powders were single-phase compounds and possessed the expected crystal structure for each synthesis approach. Scanning electron microscopy (SEM) was employed for the estimation of surface morphological features. Nitrogen adsorbtion-desorbtion (BET model) was used for evaluation of specific surface area. Nanostructure of all synthesized samples was similar (particle size ~ 20-40 nm). It was observed, that the nature of reflectance spectra strongly depends on the preparation technique used. The strongest difference in the absorbance between SGC and SG derived samples was observed in the blue region. Electrical properties of synthesized ceramic samples were studied by means of impedance spectroscopy. The results showed that the highest quality of GDC ceramics was achieved for SGC derived powders. Among the selected synthesis approaches SGC-GL was found to be most promising in terms of the highest conductivity values, the highest dielectric permittivity as well as ceramic density. In order to determine the amount of cerium and gadolinium in GDC powders, spectrophotometric method was proposed. The calibration graph for cerium and gadolinium was linear in the range of 1.0-30.0 µg/ml and 0.15-1.4 µg/ml, respectively. It was methodology and practice adapted for cerium and gadolinium determination in GDC system. Molecular absorbtion spectral analysis method yields reliable results. The relative standart deviation (n = 3) was from 4.3 to 11.9 %. |
