Combustion Synthesis of NiO/YSZ Composite

Nickel oxide-yttria stabilized zirconia (NiO-YSZ) anode materials were synthesized by combustion process involving metal nitrate-urea decomposition. The precursor was heated to evaporate water undergoing dehydration, and then the mixtures froth and swell. Further heating produces large amounts of gases that ignite at ambient atmosphere. Different nitrate/urea initial molar ratios were employed in order to investigate the influence of the reaction temperature in the physical characteristics of the powder composite. The flame temperature was measured by infrared optical pyrometer. The combustion was rapid and self-sustaining, with flame temperatures ranging from 870 to 1330°C. The as-synthesized powders were uniaxially pressed and sintered in air. Powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), helium picnometry for density measurements and gas adsorption technique (BET). The ceramic samples were evaluated by SEM and Archimedes density measurements.