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Focused ion beam assisted analysis of the oxidation of a NiAl coating on pure Ni

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Show simple item record Reid, M. Pomeroy, Michael J. Vokal, V Tanner, David A. 2014-03-05T12:41:59Z 2014-03-05T12:41:59Z 2005
dc.identifier.citation Reid, M; Pomeroy, MJ; Vokal, V; Tanner, DA (2005) 'Focused ion beam assisted analysis of the oxidation of a NiAl coating on pure Ni'. Materials at High Temperatures, 22 (3-4):421-426. en_US
dc.description peer-reviewed en_US
dc.description.abstract Discs of (pure nickel 15 mm diameter and 4 nun thickness) have been polished to a 1 mu m finish, aluminised using a standard pack CVD process to give a beta-NiAl coating and then the surface of this coating polished to a 1 mu m finish again. Samples have then been isothermally oxidised in a muffle furnace for 1, 2, 4, 8, 16, 32, 64, 128, 256, 512 and 1024 hours at 950 degrees C, and subjected to surface and cross-sectional microscopy and analysis. Scales were also cross-sectioned and imaged using Focused Ion Beam Milling. The oxidation rate was determined to be 2.6 x 10(-13) g(2) cm(-4) s(-1) and for times less than 512 hours the predominant alumina phase was theta alumina. Al depletion effects were observed due to both oxidation and interdiffusion between the Ni substrate and the NiAl coating. Using these effects, it has been shown that tensile strains of up to 9% can arise and these strains readily explain the formation of intrefacial elliptical pores observed by FIB cross sectioning. FIB sectioning also indicated that different coating grains exhibit different oxide-coating interfaces which arise due to different grain orientations. The faceting of the coating-oxide interface and the development of cuboidal faceted coating structures beneath spalled oxide is thought to be due to substructure development (sub-grain development or recrystallisation) arising from the plastic strains generated by Al depletion effects. en_US
dc.language.iso eng en_US
dc.publisher Maney Publishing en_US
dc.relation.ispartofseries Materials at High Temperatures;22 (3-4), pp. 421-426
dc.subject focused ion beam en_US
dc.subject oxidation of a NiAl coating en_US
dc.subject pure Ni en_US
dc.subject alloys en_US
dc.title Focused ion beam assisted analysis of the oxidation of a NiAl coating on pure Ni en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US 2013-11-29T16:19:54Z
dc.description.version Accepted
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US
dc.internal.rssid 1133684
dc.internal.copyrightchecked Yes
dc.description.status peer-reviewed

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