Effect of composition on the structural development and electrical conductivity of NiO-GDC composites obtained by one-step synthesis

abstract

NiO-C0.9Gd0.1O1.95 (NiO-GDC) composites obtained using a chemical route (one-step synthesis) were characterized by thermal analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy (between 300 and 650 degrees C in air). Rietveld refinement of XRD data indicated that synthesized powders are ultrafine and the crystallite size of the GDC phase decreases with increasing NiO content. The relative density of sintered samples is influenced by the NiO content, but easily brought to values above 95% after sintering at 1450-1500 degrees C. NiO-GDC composites exhibited homogeneous phase distribution and grain size often lower than 1 gm. With 30-40 wt% NiO this phase dominates the overall electrical conductivity of NiOGDC. The combination of grain size, conductivity and microstructural characteristics shows the efficacy of the adopted processing route to obtain high quality Ni-GDC cermet precursors.

keywords

OXIDE FUEL-CELLS; ANODE MATERIALS; NANOCOMPOSITE POWDERS; PARTICLE-SIZE; CERIA; TEMPERATURE; CERMETS; MICROSTRUCTURES; SINTERABILITY; PERFORMANCE

subject category

Materials Science

authors

Grilo, JPF; Moura, CG; Macedo, DA; Rajesh, S; Figueiredo, FML; Marques, FMB; Nascimento, RM

our authors

acknowledgements

The authors acknowledge CNPq (Brazil, 447797/2014-0) and FCT (Portugal) for the financial support, the latter through projects CICECO - Aveiro Institute of Materials (FCTUID/CTM/50011/2013), financed by national funds through the FCT/MEC, and when applicable, co-financed by FEDER under the PT2020 Partnership Agreement, and Investigador FCT 2013, contract number IF/01174/2013. Joao P. F. Grilo thanks CAPES (Coordenacao de Aperfeicoamento de Nivel Superior, Brazil) for the MSc Grant.

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