Plasma-sprayed gadolinium-doped ceria (GDC) for intermediate temperature solid electrolyte

10 mol% gadolinium-doped cerium (IV) oxide was prepared by solid-state reaction route and deposited as a thick film using thermal (plasma) spray technique. The phase development, microstructure and topography were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The mechanical strength of the deposited film was determined by pull-off adhesion test. The plasma-sprayed GDC was characterized for its electrical properties by dc four-probe conductivity experiments. The maximum conductivity for plasma-sprayed GDC was found to be 3.60 x 10(-2) Scm(-1), which was lesser than 2.25 x 10(-1) Scm(-1) for the CIP-sintered GDC at 1000 degrees C and pO(2) = 0.21 atm. The decrease in the conductivity is attributed to the larger intergranular spaces and uneven networking observed in the microstructure resulted in higher activation energy and low conductivity.