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Properties data for adhesion and surface chemistry of aluminum: sapphire-aluminum, single-crystal couple
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Miyoshi, Kazuhisa Whitle, Neville C. Adams, Jim Hector Jr., Louis G. Pohlchuck, Bobby |
| Copyright Year | 1998 |
| Description | An investigation was conducted to examine the adhesion and surface chemistry of single-crystal aluminum in contact with single-crystal sapphire (alumina). Pull-off force (adhesion) measurements were conducted under loads of 0. I to I mN in a vacuum of 10(exp -1) to 10(exp -9) Pa (approx. 10(exp -10) to 10(exp -11) torr) at room temperature. An Auger electron spectroscopy analyzer incorporated directly into an adhesion-measuring vacuum system was primarily used to define the chemical nature of the surfaces before and after adhesion measurements. The surfaces were cleaned by argon ion sputtering. With a clean aluminum-clean -sapphire couple the mean value and standard deviation of pull-off forces required to separate the surfaces were 3015 and 298 micro-N, respectively. With a contaminated aluminum-clean sapphire couple these values were 231 and 241 micro-N. The presence of a contaminant film on the aluminum surface reduced adhesion by a factor of 13. Therefore, surfaces cleanliness, particularly aluminum cleanliness, played an important role in the adhesion of the aluminum-sapphire couples. Pressures on the order of 10(exp -8) to 10(exp -9) Pa (approx. 10(exp -10) to 10(exp -11) torr) maintained a clean aluminum surface for only a short time (less then 1 hr) but maintained a clean sapphire surface, once it was achieved, for a much longer time. |
| File Size | 622484 |
| Page Count | 14 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19980137721 |
| Archival Resource Key | ark:/13960/t2c877b5z |
| Language | English |
| Publisher Date | 1998-04-01 |
| Access Restriction | Open |
| Subject Keyword | Nonmetallic Materials Single Crystals Vacuum Systems Chemistry Metal Surfaces Sapphire Aluminum Surface Reactions Surface Properties Auger Spectroscopy Electron Spectroscopy Adhesion Aluminum Oxides Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
