Title:
Processing of a Hybrid Solid Oxide Fuel Cell Platform

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dc.contributor.advisor Cochran, Joe K.
dc.contributor.advisor Sanders, Thomas H., Jr.
dc.contributor.author Oh, Raymond H. en_US
dc.contributor.committeeMember Garmestani, Hamid
dc.contributor.committeeMember McDowell, David
dc.contributor.committeeMember Speyer, Robert
dc.contributor.department Materials Science and Engineering en_US
dc.date.accessioned 2006-06-09T17:50:31Z
dc.date.available 2006-06-09T17:50:31Z
dc.date.issued 2006-01-09 en_US
dc.description.abstract Solid oxide fuel cell platforms consisting of alternating cellular layers of yttria-stabilized zirconia electrolyte and Fe-Ni metallic interconnects (Fe45Ni, Fe47.5Ni, Fe50Ni) were produced through the co-extrusion of two particulate pastes. Subsequent thermal treatment in a hydrogen atmosphere was used to reduce iron and nickel oxides and co-sinter the entire structure. Issues surrounding this process include the constrained sintering of the layers and the evolution of residual stress between the dense, fired layers. Sintering curves for individual components of the layers were measured by dilatometry to ascertain each materials impact on overall sintering mismatch. X-ray diffraction, scanning electron microscopy and weight loss were utilized to examine phase evolution within the Fe-Ni alloys during reduction. YSZ powders densified above ~1050C and shrinkage was rapid above the sintering temperature. Shrinkage of the interconnect occurred in two stages: reduction and the initial stages of sintering concluded around ~600C, plateauing shortly and continuing at ~900C as pore removal and grain growth ensued simultaneously. Constrained sintering resulted in the formation of remnant porosity within the interconnect layers. Interconnect compositions were chosen in efforts to minimize disparities in thermal expansion with the electrolyte. Residual strains on the surfaces of the layers were measured by x-ray diffraction. Corresponding stresses were calculated using the sin2y method. Grain growth within the interconnect prohibited random planes to be measured so stress measurements were confined to the ceramic layers. Various material properties such as thermal expansion were collected and employed in a modified finite element model to estimate residual stresses in the platform. A method for determining a crucial parameter, the zero stress temperature was outlined and incorporated. Modeled values were found to agree well with XRD values, providing indirect confirmation of the zero stress temperature calculations. Discrepancies were attributed to microcracks found within the layer that arose due to residual stress values surpassing the tensile strength of the zirconia. en_US
dc.description.degree Ph.D. en_US
dc.format.extent 6081962 bytes
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/10429
dc.language.iso en_US
dc.publisher Georgia Institute of Technology en_US
dc.subject Solid oxide fuel cells en_US
dc.subject Extrusion
dc.subject Co-sintering
dc.subject Residual stress
dc.subject.lcsh Solid oxide fuel cells en_US
dc.subject.lcsh Residual stresses en_US
dc.title Processing of a Hybrid Solid Oxide Fuel Cell Platform en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Cochran, Joe K.
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 2b909350-b1f8-4e17-b9e5-9e7a63b5aa8c
relation.isOrgUnitOfPublication 21b5a45b-0b8a-4b69-a36b-6556f8426a35
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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