Effects of additives and impurity on the adhesive behavior of the NiAl(110)/Al2O3 (0001) interface: An Ab Initio study

  1. Get@NRC: Effects of additives and impurity on the adhesive behavior of the NiAl(110)/Al2O3 (0001) interface: An Ab Initio study (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1007/s11661-011-0813-x
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Journal titleMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Pages41264136; # of pages: 11
SubjectAb initio; Ab initio study; Adhesive strength; Al oxide; Atomic-scale mechanisms; Co-doping; Detrimental effects; Electron density of state; Electron localization function; Impurity element; RE additions; Reactive elements; Synergistic effect; Synergistic interaction; Work of separation; Adhesion; Alloying elements; Aluminum; Density functional theory; Electronic structure; Hafnium; Platinum; Separation; Sulfur; Thermal barrier coatings; Zirconium; Chromium
AbstractUsing ab initio density functional theory (DFT), the adhesive behavior of NiAl(110)/Al2O3(0001) interface in thermal barrier coatings was systematically studied with an emphasis on the effects of alloying additives and impurity elements. To reveal possible atomic-scale mechanisms, the separations between certain atoms at the interface, the electron localization function (ELF), and the electron density of states (DOS) are thoroughly investigated. First, effects of individual elements such as S, Pt, and Cr, and reactive elements (REs) Hf, Zr, and Y, on the work of separation, W sep, of the interface were examined. As expected, the segregation of S to the interface significantly degrades the adhesion, while the substitution of Pt for Ni adjacent to the interface does not enhance the W sep. Cr and RE addition to the interface individually result in a considerable increase of W sep. Second, the addition of Pt, Hf, and Cr to the S containing interface is shown to mitigate the detrimental effect of sulfur to some extent. Co doping the interface with a selected combination of (Pt, Hf), (Pt, Cr), (Cr, Hf), (Cr, Y), (Hf, Y), and (Y, Zr) was implemented to probe possible synergistic interactions between elements on W sep. Synergistic effects are detected on increasing W sep for (Hf, Y), (Hf, Zr) combinations. Co doping the interface with (Cr, Y) and (Cr, Hf), however, is found to weaken the adhesion. Through a detailed analysis of electronic structures in terms of ELF and DOS, four dominant bonds across the interface, RE-O, RE-Ni, Aloxide-Ni, and AlNiAl-O, are identified to play a decisive role in governing the adhesive strength of the interface. © 2011 The Minerals, Metals & Materials Society and ASM International.
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AffiliationNational Research Council Canada (NRC-CNRC); Aerospace (AERO-AERO)
Peer reviewedYes
NPARC number21271434
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Record identifier830ec9c9-5e0e-4f19-bc6c-6a088698a37e
Record created2014-03-24
Record modified2016-05-09
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