Title:
Surface Modifications of Steels to Improve Corrosion Resistance in Sulfidizing-Oxidizing Environments

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dc.contributor.advisor Singh, Preet M.
dc.contributor.author Behrani, Vikas en_US
dc.contributor.committeeMember Frederick, William
dc.contributor.committeeMember Liu, Meilin
dc.contributor.committeeMember Sanders, Thomas
dc.contributor.committeeMember Thadhani, Naresh N.
dc.contributor.department Materials Science and Engineering en_US
dc.date.accessioned 2008-02-07T18:11:53Z
dc.date.available 2008-02-07T18:11:53Z
dc.date.issued 2007-09-26 en_US
dc.description.abstract Industrial and power generation processes employ units like boilers and gasifiers to burn sulfur containing fuels to produce steam and syn gas (H2 and CO), which can generate electricity using turbines and fuel cells. These units often operate under environments containing gases such as H2S, SO2, O2 etc, which can attack the metallic structure and impose serious problems of corrosion. Corrosion control in high temperature sulfur bearing environments is a challenging problem requiring information on local gaseous species at the surface of alloy and mechanisms of degradation in these environments. Coatings have proved to be a better alternative for improving corrosion resistance without compromising the bulk mechanical properties. Changes in process conditions may result in thermal and/or environment cycling between oxidizing and sulfidizing environments at the alloy surface, which can damage the protective scale formed on the alloy surface, leading to increase in corrosion rates. Objective of this study was to understand the effect of fluctuating environments on corrosion kinetics of carbon steels and develop diffusion based coatings to mitigate the high temperatures corrosion under these conditions. More specifically, the focus was : (1) to characterize the local gaseous environments at the surface of alloys in boilers; (2) optimizing diffusion coatings parameters for carbon steel; (3)understand the underlying failure mechanisms in cyclic environments; (4) to improve aluminide coating behavior by co-deposition of reactive elements such as Yttrium and Hafnium; (5) to formulate a plausible mechanism of coating growth and effects of alloying elements on corrosion; and (6) to understand the spallation behavior of scale by measuring stresses in the scales. The understanding of coating mechanism and effects of fluctuating gaseous environments provides information for designing materials with more reliable performance. The study also investigates the mechanism behind the effect of REs on scale adhesion and sulfidation behavior. Thus, the present work will have a broad impact on the field of materials and coatings selection for high temperature industrial environments such as boilers and gasifiers, and provides information on RE-modified aluminized coatings on carbon steel as an alternative for the use of bulk superalloys under high temperature sulfur bearing environments. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/19708
dc.publisher Georgia Institute of Technology en_US
dc.subject Sulfidation en_US
dc.subject Oxidation en_US
dc.subject Coatings en_US
dc.subject Reactive-element en_US
dc.subject Cementation en_US
dc.subject Aluminide en_US
dc.subject.lcsh Carbon steel
dc.subject.lcsh Corrosion resistant materials
dc.subject.lcsh Sulfur compounds
dc.subject.lcsh Protective coatings
dc.subject.lcsh High temperature chemistry
dc.title Surface Modifications of Steels to Improve Corrosion Resistance in Sulfidizing-Oxidizing Environments en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Singh, Preet M.
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 436052a4-5726-4887-bdbf-e726647a6d26
relation.isOrgUnitOfPublication 21b5a45b-0b8a-4b69-a36b-6556f8426a35
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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