Download Free The Thickness Dependence Of Oxygen Permeability In Sol Gel Derived Cgo Cofe2o4 Thin Films On Porous Ceramic Substrates Book in PDF and EPUB Free Download. You can read online The Thickness Dependence Of Oxygen Permeability In Sol Gel Derived Cgo Cofe2o4 Thin Films On Porous Ceramic Substrates and write the review.

Mixed conductive oxides are a topic of interest for applications in oxygen separation membranes as well as use in producing hydrogen fuel through the partial oxidation of methane. The oxygen flux through the membrane is governed both by the oxygen ionic conductivity as well as the material's electronic conductivity; composite membranes like Ce{sub 0.8}Gd{sub 0.2}O{sub 2-{delta}} (CGO)-CoFe2O4 (CFO) use gadolinium doped ceria oxides as the ionic conducting material combined with cobalt iron spinel which serves as the electronic conductor. In this study we employ ≈ 50 nm sputtered CeO2 layers on the surface of porous CGO ceramic substrates which serve as solution 'blocking' layers during the thin film fabrication process facilitating the control of film thickness. Films with thickness of ≈ 2 and 4 microns were prepared by depositing 40 and 95 separate sol-gel layers respectively. Oxygen flux measurements indicated that the permeation increased with decreasing membrane thickness; thin film membrane with thickness on the micron level showed flux values an order of magnitude greater (0.03 [mu]mol/cm2 s) at 800 C as compared to 1mm thick bulk ceramic membranes (0.003 [mu]mol/cm2).
This book focuses on research related to ionic conducting (e.g., protons, oxygen ions) materials and devices. Contributions range from fundamental materials R&D, to characterization, to materials for batteries, sensors, membranes, supercapacitors and fuel cells. Special emphasis is given to miniaturized solid-oxide fuel cells (micro-SOFCs), from fundamental materials studies which are still very much needed for this application, to the development of devices. Innovative concepts for energy storage are also discussed.
A process for the deposition of sol-gel derived thin films on porous substrates has been developed; such films should be useful for solid oxide fuel cells and related applications. Yttria-stabilized zirconia films have been formed from metal alkoxide starting solutions. Dense films have been deposited on metal substrates and ceramic substrates, both dense and porous, through dip-coating and spin-coating techniques, followed by a heat treatment in air. X-ray diffraction has been used to determine the crystalline phases formed and the extent of reactions with various substrates which may be encountered in gas/gas devices. Surface coatings have been successfully applied to porous substrates through the control of substrate pore size and deposition parameters. Wetting of the substrate pores by the coating solution is discussed, and conditions are defined for which films can be deposited over the pores without filling the interiors of the pores. Shrinkage cracking was encountered in films thicker than a critical value, which depended on the sol-gel process parameters and on the substrate characteristics. Local discontinuities were also observed in films which were thinner than a critical value which depended on the substrate pore size. A theoretical discussion of cracking mechanisms is presented for both types of cracking, and the conditions necessary for successful thin formation are defined. The applicability of these film gas/gas devices is discussed.