Structure and adhesion of MoSi2/Ni interfaces: Evaluation of MoSi2 as an alternative bond coat alloy

Donald F. Johnson, Emily A. Carter

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

We use density functional theory to evaluate the stability of molybdenum disilicide coatings on a nickel substrate, as a possible bond coat alloy for high temperature coating applications. We consider the MoSi2(0 0 1)/Ni(1 1 1), MoSi2(1 0 0)/Ni(1 1 1), and MoSi2(1 1 0)/Ni(1 1 1) interfaces and predict quite strong (3.5-3.8 J/m2) adhesion of this metal-silicide ceramic to nickel. The origin of this strong adhesion is elucidated by examining the geometric and electronic structure of the interfaces. We predict that Mo and Si atoms at the interface primarily occupy Ni 3-fold hollow sites, the typical adsorption site on Ni(1 1 1). Projected local densities of states and electron density difference plots reveal a mixture of localized, covalent Si-Ni bonds and more delocalized metallic Mo-Ni bonding, as the origin of the strong interfacial bonding. As emphasized in our earlier work, creation of strong covalent bonds at interfaces results in very strong adhesion. Such strong adhesion makes MoSi2 a potential candidate for use in thermal barrier applications, in conjunction with a yttria-stabilized zirconia topcoat.

Original languageEnglish (US)
Pages (from-to)1276-1283
Number of pages8
JournalSurface Science
Volume603
Issue number9
DOIs
StatePublished - May 1 2009

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Keywords

  • Adhesion
  • Coatings
  • Density functional calculations
  • Nickel

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