Effects of segregating elements on the adhesive strength and structure of the α-Al2O3/β-NiAl interface
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- 作者：Karin M. Carling ; Emily A. Carter
- 刊名：Acta Materialia
- 出版年：2007
- 出版时间：May 2007
- 年：2007
- 卷：55
- 期：8
- 页码：2791-2803
- 全文大小：832 K
文摘
We investigate with first-principles density functional theory (DFT) the adhesion of the Al2O3(0 0 0 1)/NiAl(1 1 0) interface as a model for the thermally grown oxide/bond coat alloy interface in thermal barrier coatings. We find that the clean interface has an ideal work of adhesion of 0.66 J m−2. We predict that S impurities reduce interfacial adhesion significantly, due to a reduction in cross-interface bonds. The presence of Pt alters the interface adhesion only slightly, while Hf dopants dramatically increase adhesion via formation of strong Hf–O bonds, as expected from Hf’s open-shell character. We discuss the implications of these predictions, which are consistent with experimental observations of the effects of S, Pt, and Hf on the lifetime of thermal barrier coatings.