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Interfacial Stoichiometry and Adhesion at Metal/α‐Al 2 O 3 Interfaces
Author(s) -
Li HongTao,
Chen LianFeng,
Yuan Xun,
Zhang WenQing,
Smith John R.,
Evans Anthony G.
Publication year - 2011
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.1551-2916.2011.04405.x
Subject(s) - stoichiometry , ionic bonding , materials science , metal , oxide , covalent bond , adhesion , chemical physics , crystallography , chemistry , composite material , metallurgy , ion , organic chemistry
First‐principles studies of metal/α‐Al 2 O 3 interfaces have revealed strong interfacial stoichiometry effects on adhesion. The metals included Al, Ni, Cu, Au, Ag, Rh, Ir, Pd, Pt, Nb, and β‐NiAl. Metallic and ionic‐covalent adhesive bonding effects were found in varying amounts depending on whether the interfacial stoichiometry is stoichiometric, oxygen‐rich, or aluminum‐rich in a qualitative way. A semiempirical but physically sensible understanding ensues for the effects of interfacial stoichiometry and reveals the underlying strong correlation of the interfacial adhesion with the physical properties of the bulk materials that join and form the interface. The metallic component of the bonding was found to be related to the ratio of (B/V) 1/2 , where B and V are the bulk modulus and molar volume of the metal, respectively. In like manner, the ionic‐covalent component of the bonding could be related to the enthalpy of oxide formation of the bulk metal. A unified model is proposed to describe the adhesion of metal/alumina interfaces with interfacial stoichiometry effects, and the model is also expected to be valid for other metal–oxide interfaces.