Chemical and electrical features of the interphase: electrode-electrolyte in the system (Y,Ca)MnO3-CeO2-Y2O3

The scope of this paper is to report the results obtained about the solid s tate phase relations in the interfacial region for a system consisting of Y 2O3-modified CeO2 solid electrolyte and Y0.7Ca0.3MnO3-based ceramic electro de. The ceria-yttria solid electrolyte has been doped with CaO for improvin g the grain boundary conductivity, according to the results described elsew here. The electrode was fixed on the electrolyte by powder pressing and the sandwich was cofired at several temperatures. The microstructure was obser ved with Scanning Electron Microscopy (SEM), and the reaction products were established by X-Ray Diffraction (XRD) of the cofired materials. Complex I mpedance Spectroscopy was used for determining the total electrical conduct ivity and the electrical behaviour of the interphase electrode-electrolyte. The boundary region between the electrode and the electrolyte showed no re action phases. The complex impedance measurements indicate that the (Y,Ca) manganites have the conductivity comparable to that of the Ag electrodes. ( C) 2001 Elsevier Science B.V. All rights reserved.