Shear strength of aluminum-sapphire interfaces

• Published in: Materials letters 1989-11, Vol.8 (11), p.481-485
• Main Authors: Ott, J.P., Michal, G.M., Chottiner, O.S.
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals, semimetals and alloys; Metals. Metallurgy; Physics; Solid surfaces and solid-solid interfaces; Specific materials; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/0167-577X(89)90036-0

Interfacial shear strength tests were conducted at room temperature in an ultrahigh-vacuum environment on aluminum-sapphire interfaces prepared from four different combinations of polycrystalline aluminum and basal plane sapphire surfaces. The adhesive strengths developed across interfaces prepared from UHV cleaned, and also UHV cleaned then dosed with 1000 langmuir of oxygen, aluminum and sapphire surfaces were found to be greater than the adhesive strength of the aluminum metal to itself. Interfaces made from UHV cleaned aluminum and ambient air exposed sapphire produced lower adhesion and a shear coefficient of 0.7 in contrast to the shear coefficient of 0.8 developed by interfaces where both surfaces were initially UHV cleaned. Interfaces made from ambient air exposed aluminum and sapphire surfaces developed a shear coefficient of only 0.2 when tested at low normal loads. At high normal loads adhesion increased causing the shear coefficient value of those interfaces to rise to 0.7.