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Author Saadi, Souheil
Sponsorship USDOE
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
File Format PDF
Language English
Subject Keyword NATURAL GAS ♦ ADSORPTION ♦ ALLOYS ♦ CARBON ♦ CORROSION ♦ FUNCTIONALS ♦ GRAPHITE ♦ OXIDES ♦ PHASE DIAGRAMS ♦ PROTECTIVE COATINGS ♦ SPALLATION ♦ STABILITY ♦ STEAM ♦ CHEM, MATSCI
Abstract We investigate the structure and surface composition of the {gamma}{prime}-Ni{sub 3}Al(111) and {beta}-NiAl(110) alloy surfaces at conditions relevant for metal dusting corrosion related to catalytic steam reforming of natural gas. In regular service as protective coatings, nickel-aluminum alloys are protected by an oxide scale, but in case of oxide scale spallation, the alloy surface may be directly exposed to the reactive gas environment and vulnerable to metal dusting. By means of density functional theory and thermochemical calculations for both the Ni{sub 3}Al and NiAl surfaces, the conditions under which CO and OH adsorption is to be expected and under which it is inhibited, are mapped out. Because CO and OH are regarded as precursors for nucleating graphite or oxide on the surfaces, phase diagrams for the surfaces provide a simple description of their stability. Specifically, this study shows how the CO and OH coverages depend on the steam to carbon ratio (S/C) in the gas and thereby provide a ranking of the carbon limits on the different surface phases.
ISSN 00396028
Educational Use Research
Learning Resource Type Article
Publisher Date 2011-03-01
Publisher Place United States
Journal Surface Science
Volume Number 605
Issue Number 5-6
Technical Publication No. SLAC-PUB-14366
Organization SLAC National Accelerator Lab., Menlo Park, CA (United States)


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