Electrical and microstructural properties of Yb-doped CeO₂

Abstract

Nanopowdered Ce 1−x Yb x O 2−ı solid solutions (0 ≤ x ≤ 0.2) were synthesized by a self-propagating room temperature synthesis. XRD and SEM were used to study the properties of these materials as well as the Yb solubility in CeO 2 lattice. Results showed that all the obtained powders were solid solutions with a fluoritetype crystal structure and with nanometric particle size. The average size of Ce 1−x Yb x O 2−ı particles was approximately 3 nm. Electrochemical impedance spectroscopy for the sintered pellets depicted that it was possible to separate R bulk and R gb in the temperature interval of 550-800 • C. The activation energy for the bulk conduction was 1.03 eV and for grain boundary conduction was 1.14 eV. Grain boundary resistivity dominates over the other resistivities. These measurements confirmed that Yb 3+-doped CeO 2 material had a potential as electrolyte for intermediate-temperature solid oxide fuel cell applications.

Effects of Mg2+ addition on structure and electrical properties of gadolinium doped ceria electrolyte ceramics

“…It can be seen that no secondary phase could be identified. According to previous studies, doping with ions having different valences and different ionic radii will change the lattice parameter of ceria and induce corresponding oxygen vacancies generate the internal stress in the ceria matrix [21][22][23]. The lattice parameters of the prepared Ce 0.8 Gd 0.2-x Mg x O 1.9-δ samples are basically not changed considerably with the Mg-doping concentration, and remained a = b = c = 0.5418 nm.…”

Efeito da adição de zircônia estabilizada com céria nas propriedades mecânicas de compósitos à base de alumina

“…O ensaio de erosão gera resultados que possibilitam comparar os comportamentos dos materiais ensaiados nas mais diferentes situações de uso a que possam ser submetidos; entretanto, a comparação de resultados entre um e outro trabalho é dificultada, devido à diferença nos parâmetros aplicados nos ensaios, sejam eles na velocidade de impacto, ângulo, temperatura ou granulometria do erodente (Gonçal-ves, 2011;Matović et al 2014;Tiboni, 2011). Para materiais cerâmicos, a situação mais crítica de erosão é a mesma que foi aplicada no ensaio dos corpos de prova deste trabalho.…”

Sintering and electrical properties of Ce 1 − x Bi x O 2 − δ solid solution

“…When the resistive components in the semicircle were clearly separated, i.e., R b C b ( R gb C gb , where bulk capacitance (C b ) is typically few orders of magnitude lower than C gb , the values of R b and R gb may be read separately as intercepts of the semicircles with the real axis [35]. At impedance graph of the sample Ce 0.8 Bi 0.2-O 2Àd (Fig.…”