Sintering behaviour and electrical properties of gadolinia-doped ceria modified by addition of silicon oxide and titanium oxide

The small amount (0.25 wt. ) of SiO_X and TiO_X as sintering aids was added to gadolinia-doped ceria (GDC) powder for densifying solid electrolytes by sol-gel method. Material characteristics of the prepared and calcined electrolytes were identified by X-ray diffraction for crystalline structures, Brunauer-Emmett-Teller measurements for surface, area and scanning electron microscopy for surface morphology and microstructures. The route process of doping SiO_X and TiO_X as sintering aid in GDC electrolytes not only suppresses crystallite growth to form the ultrafine particle, but also lowers the sintering temperature for the densification process of bulk electrolyte by active sintering or liquid phase sintering. Additionally, doping a small amount of SiO_X and TiO_X also increases the relative density of the bulk electrolyte and the total conductivity. Material produced in this way could be recommended as solid electrolyte layers for solid oxide fuel cell systems to be densifying the compared with the well-known yttria-stabilised zirconia.