Solid State Ionics, Vol.98, No.1-2, 63-72, 1997
Electrochemical Vapor-Deposition Synthesis and Oxygen Permeation Properties of Dense Zirconia-Yttria-Ceria Membranes
Thin (< 15 mu m) dense ZrO2-Y2O3-CeO2 membranes with different CeO2 composition and membrane thickness were deposited on porous alpha-alumina substrates by the EVD process using corresponding metal chlorides as the precursors. CeO2 composition in the membrane is the same as CeCl3 concentration in the gas phase. The film growth rate for the EVD process is about 7 mu m/h. The EVD prepared ZrO2-Y2O3-CeO2 membranes do not show single phase, but consist of two separate phases : a ZrO2-dominant cubic phase and a CeO2-dominant cubic phase. Under present conditions (950-1050 degrees C, P-O2(high)=0.21 atm, P-O2(low)=0.01 arm), oxygen permeation through the EVD prepared ZrO2-Y2O3-CeO2 membranes is limited by the bulk diffusion in the membrane. The oxygen permeability of the ZrO2-Y2O3-CeO2 membranes is in the range of 1-4X10(-11) mol/cm s, about an order of magnitude higher than that of ZrO2-Y2O3 membranes. The oxygen permeation flux through the EVD prepared ZrO2-Y2O3-CeO2 membrane increases with CeO2 composition in the film.