Long-Term Chemical Stability of BaCe0,85Y0,15O3-d + Ce0,85Y0,15O2-d Composite Samples at Room Temperature and at 873 K for Use in Dual Pcfc-Sofc Fuel

The goal of this work is to compare the long-term chemical stability of BaCe0,85Y0,15O3-? and Ce0,85Y0,15O2-? bulk composite samples to that of pure BaCe0,85Y0,15O3-? after ageing for 600 hours in CO2/H2O atmosphere at room temperature and N2/H2O atmosphere at 873 K. Differential Thermal Analysis and Thermogravimetry were used to investigate the physic- ochemical processes that took place during the ageing of the afore-mentioned samples and the chemical composition of the gases released from the samples was analyzed by a Mass Spectrometer. The influence of the reactive atmospheres on phase and chemical composition, as well as the microstructure of the bulk samples, was determined from X-ray Diffraction results and Scanning Electron Microscopy observations combined with Energy Dispersion Spectroscopy analysis. From these studies it can be concluded that the composite materials are capable of maintaining stability in the studied conditions, however, pure BaCe0,85Y0,15O3-? is unstable in CO2/H2O atmosphere at room temperature. Keywords: perovskites, solid oxide fuel cell electrolytes, chemical stability, composite materials