The influence of interface impurities on fracture energy of UHV diffusion bonded metal-ceramic bicrystals

Journal Article · Sat Oct 15 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90523-1· OSTI ID:6887539

Elssner, G; Korn, D; Ruehle, M ^[1]

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1. Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany). Inst. fuer Werkstoffwissenschaft

In both the practical and theoretical aspects of joining metals to ceramics the influence of impurities on the interfacial bond strength is not fully understood. In the present paper the authors describe part of a study in which the interface of niobium-sapphire bicrystals was contaminated under defined conditions and the interfacial fracture energy of these UHV diffusion bonded bicrystals was determined as a measure of their bond strength. The model combination niobium-sapphire shows at high temperatures a simple reaction in which alumina dissolves in niobium without forming an interlayer. Furthermore, niobium and sapphire are characterized by nearly the same expansion behavior which minimizes the development of thermal stresses during cooling down from the bonding temperature. The authors report on experiments in which silver or titanium atoms have been chosen as interfacial impurity elements. Silver is practically insoluble in niobium and sapphire whereas titanium possesses a highly negative free enthalpy of oxide formation. It is assumed that both these properties are associated with interfacially active elements in the system niobium-sapphire.

• OSTI ID: 6887539
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 31:8; ISSN SCRMEX; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BONDING
CHALCOGENIDES
COMPOSITE MATERIALS
DATA
ELEMENTS
EXPERIMENTAL DATA
FABRICATION
FRACTURE PROPERTIES
INFORMATION
INTERFACES
JOINING
MATERIALS
MECHANICAL PROPERTIES
METALS
NIOBIUM
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENTS