The effect of platinum on defect formation energies in β-NiAl

First-principles density functional theory is used to examine the effect of Pt on point defects and defect clusters in NiAl. It is found that Pt promotes the formation of Ni and Al vacancies and Ni and Al antisite atoms. Defect clusters that are minima in postulated Ni diffusion mechanisms in NiAl are also found to be stabilized by the presence of Pt. By decreasing defect formation energies, Pt may decrease the overall activation barrier to the diffusion of Ni and Al in NiAl. The results provide clues as to how Pt enhances thermal barrier coating lifetime.