ELECTROCHEMICAL FORMATION OF THIN CERAMIC MIXED CONDUCTING MEMBRANES FOR OXYGEN SEPARATION

THIS PROPOSED PROGRAM ADDRESSES THE NEED FOR DEVELOPMENT OF THIN CERAMIC MEMBRANES FOR ACHIEVING RELIABLE OXYGEN SEPARATION AT ELEVATED TEMPERATURES. TECHNICAL EFFORT WILL BE DIRECTED TOWARDS DEVELOPMENT OF AMBIENT TEMPERATURE ELECTROLYTIC TECHNIQUE FOR THE PREPARATION OF THIN FILM CERAMIC MIXED IONIC AND ELECTRONIC CONDUCTORS (MIEC) FOR USEAS OXYGEN SEPARATION MEMBRANES. THESE MEMBRANES WILL BE BASED ON PEROVSKITES OF COMPOSITIONS RE1-XAXCO1-YBYO3-A (WHERE THE RARE EARTH METAL (RE) WILL BE SELECTED FROM LA, ND, SM, GD, DY, ER, YB; A FROM BA, SR, AND CA AND B FROMFE, NI AG AND CU. THIS WILL BE PERFORMED BY INITIALLY PREPARING A TAPE CAST CONDUCTIVE CERMET OF CARBON AND YTTRIA STABILIZED ZIRCONIA (YSZ) BY MIXING GRAPHITE AND YSZ POWDER FOLLOWED BY SINTERING THE MIXTURE UNDER AN INERT ATMOSPHERE SUCH AS ARGON OR NITROGEN. THIS STRUCTURE WILL SERVE TWO PURPOSES: FIRST IT WILL PROVIDE A CONDUCTIVE SUBSTRATE ONTO WHICH ELECTRODEPOSITION OF PEROVSKITE FILMS CAN BE PERFORMED, AND SECONDLY BY TAKING THE CERMET AND ELECTRODEPOSITED FILM UP TO 700-900 DEGREES CENTIGRADE UNDER AIR THE GRAPHITE WILL BURN OUT LEAVING A HIGHLY POROUS YSZ STRUCTURE ONTO WHICH THE PEROVSKITE FILM IS SUPPORTED. THE PERFORMANCE CHARACTERISTICS OF MIEC MEMBRANES SUPPORTED ON POROUS YSZ FOR SEPARATION OF ATMOSPHERIC OXYGEN AT ELEVATED TEMPERATURES WILL BE DETERMINED.