Premium
Hf ‐Doped Ni – Al 2 O 3 Interfaces at Equilibrium
Author(s) -
Meltzman Hila,
Besmann Theodore M.,
Kaplan Wayne D.
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2012.05434.x
Subject(s) - chemistry , materials science
In this study, a series of solid‐state dewetting experiments of pure and Hf ‐doped Ni films on sapphire and Hf O 2 substrates were conducted in order to measure the change in interfacial energy of the Ni – Al 2 O 3 interface in the presence of Hf , and to study Hf interfacial segregation. It was found that Hf oxidizes under the conditions of the experiment ( P ( O 2 )=10 −20 atm), Hf does not segregate to the Ni – Al 2 O 3 interface, and that the interface energy of Ni – Hf O 2 is 2.7 ± 0.4 J/m 2 vs 2.16 ± 0.2 J/m 2 for the Ni – Al 2 O 3 interface. This contradicts several theoretical studies that predict that Hf segregates to the interface to stabilize it thermodynamically. The solubility of Hf in bulk Ni was found to be significantly lower than the value reported in the equilibrium phase diagram.